BOUGHT WITH THE INCOME
FROM THE
SAGE ENDOWMENT FUND
THE GIFT OF
1891
AjM^s'f- ^.^/
Cornell University Library
TN 145.125 1898
A manual of minlng.Based on the course o
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The original of tiiis bool< is in
tine Cornell University Library.
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http://www.archive.org/details/cu31 9240041 2351 3
A
MANUAL OF MINING.
BASED ON THE COURSE OF LECTURES ON MINING
DELIVERED AT THE SCHOOL OF MINES'
OF THE STATE OF COLORADO-
M. C. IHLSENG, C.E., E.M., Ph.D.,
Formerly of Columbia Coll-gv Soliool of Mines, Neio York City;
DEAN OF THE SCHOOL OY MINKS Ol" THE PENNSYLVANIA STATE COLLEGE.
THIRD REVISED AND ENLARGED EDITION.
FIRST THOUSAND.
NEW YORK:
JOHN WILEY & SONS.
London : CHAPMAN & HALL, Limited.
i8q8.
Copyright, 1892, 1898.
BY
M. C. IHLSEN&,
BERT DRUMIMOND, KLECTROTVPER AND PRINTER, NENV YORK.
TO
©gdcn in. 1RooC>, a./lft.,
9ROFr3S0R OF PHYSICS COLUMBIA COLLEGE, HEW YORK ClTV»
WITH RESPECT AND ADMIRATION, THIS
VOLUME IS DEDICATED
BY
THL AUTHOR.
PREFACE.
This treatise is an abbreviation of a course of lectures
upon mining, delivered at the School of Mines of the State of
Colorado, and is issued with the advice of its Board of Trustees,
which recognizes the importance of having, within a moderate
compass, the best information obtainable upon this subject.
In its presentation, the writer has followed what his own ex-
perience has taught him to be the natural sequence, and has
endeavored to introduce such matter as sixteen years of lectur-
ing and field work have suggested as requisite. Part I contains
a brief geological review and a discussion of such points as the
engineer must include in his report, i.e., the preparatory and
development work, systems of mining and the plant for power,
hoisting, pumping, and ventilation. Part II embraces the
practice of prospecting, drilling, blasting, shafting, tunnelling,
and timbering, in addition to some remarks upon the examina-
tion of mines.
The work is designed as an elementary treatise for the use
of those desiring a reference-book. The complexity of the
subject, its extent, and the variety of machines to be described
and represented, demand an elaborate discussion that would
fill several quartos. Descriptions of obsolete and expensive
systems or machinery are relegated to the historical works on
mining. American and foreign practice is described,' and sug-
gestions for lines of future progress are offered herein. The
prmciples of the construction and operation of machines used
in mining are explained with a perspicuity and conciseness
compatible with the field in which this publication is to be
sown — among students and mining men, to whom a knowledge
V
Vi PREFA CE.
of the fundamenta of their work is valuable, but whose ac-
quaintance with the theory is slight.
The wants of the latter class have been kept in mind, and
the writer hopes that the manual may prove of some benefit
to the intelligent reader, of whom it presupposes an elementary
knowledge of the sciences and of the simple machines.
The author regrets his inability to deal with the subject of
" electricity in mining" as it deserves. Two reasons account
for this : insufficient data, as yet ; and the large space which a
satisfactory explanation of the principles would demand.
The writer would also beg leave to say that the literature
of mining and its cognate branches has supplied much of the
material contained herein. References could not be made for
each hint obtained, but obligations are acknowledged to the
authors of the publications mentioned, to which the reader is
referred for further details. The information has been gar-
nered from the best available sources and condensed. The
Engineering and Mining Journal, the Colliery E^igineer, and the
transactions of \h.& Americati Institute of Mining Engineers have
been copiously drawn from, as also the experience of the prac-
tical men, to a long list of whom the Author is indebted for
many courtesies. Finally, to the manufacturers and engineers
thanks are rendered for the use of the electrotypes, which
have so largely contributed to make the work attractive.
Magnus C. Ihlseng.
Golden, Colorado, Nov,, 1891.
PREFACE TO THE THIRD EDITION.
Ix the present issue the text has been increased by more
than fifty pages in order to introduce additional matter jier-
taining to the design of cars, hoisting apphances, and fans,
the added illustrations having been specially prepared with
that end in view. At the end of each chapter will be found
a list of memoirs which have been carefully selected to com-
prehend the latest literature on the subject. The original
intent to also enter at some length upon a discussion of the
applications of electricity to mining vras abandoned after a
number of fruitless efforts to compress the matter into the
small compass which it should occupy in a work of this
nature.
It is gratifying to observe the progress made in the in-
creased economy in the utilization of power. The growth of
the \-oung giant among the motor fluids in the anthracite
regions is [particularly noticeable ; while that of electricity in
its various ajjplications in bituminous mines is rapid and sure.
It may be true that the adoption of these motor agents by
mining engineers has been a little slow, but this wise con-
servatism is dictated by the knowledge that a single acci-
dent resulting from the introduction of an innovation
might precipitate a peremptory legislative prohibition which
would render the outlay entirely useless, and it is with reluc-
tance that they must frequently forego the advantages of some
possible economic installation.
It is gratifying to observe the extended employment of
Vlll FKEFACE TO THE THIRD EDITION.
artificial methods of ventilation in the metalliferous mines of
the West, and \vhen the American method of " square sets "
shall have been supplanted entirely by the method of rock-
filling, or of flushing- with waste, the dangers to life and prop-
erty will have been further reduced and the economy of
mining materially increased.
Regarding the enlargement of the chapter on explosives
and the stress laid upon the necessity for an absolute prohibi-
tion of black powder from the coal mines, I hope they may
be fruitful of results.
Finally, there has been added at the end of each chapter a
list of the more important memoirs dealing with the subject
matter of that chapter, and this, carried to the close of the
year 1897, has brought the work up to date. It should prove
of good service as a syllabus.
The author hopes that the book in its revised form iviU
contribute to a better circulation of the knowledge of the
principles upon which mining engineering is founded.
Magnus C. Iiilseng.
State College, Pa., Dec. 20, 1897.
CONTENTS
PART I.
MINING ENGINEERING.
CHAPTER I.
PAGE
Geognosy, .,,..,..„„;, i
I, Bird's-eye view of the subject ; native metals, minerals, ores,
and their occurrences; defiiiitions. 2. Vein matter; gangue
and gouge ; geognosy of ore-deposits; gash and fissure veins ;
beds and blankets; geological theories and miners' rules ; pre-
judices and fallacies regarding oie-deposits. 3. Prospecting;
searching for veins ; indications; float, shode, and slide rock;
examining new districts; divining-rods, spiritual mediums, and
the drill as miners. 4. Remarks upon the chaotic state of the
U. S. mining laws; apex vs. side lines; safety in the side-line
law ; advice to locators ; insecurity of locations on the apex ;
patenting claims. References.
CHAPTER II.
Preparatory and Exploratory Work, ..... 20
5. Discussion of the means of reaching veins by shafts, slopes,
tunnels, and adits; conditions and comparative advantages;
dimensions of the entries. 6. Levels, drifts, and gangways ;
necessity for, and positions of, reserves ; size of lifts and stopes ;
ratio of dead work to stoping ground ; dimensions and extent
of gangways; cleats and their influence; mode of finding the
ix
CON TENTS.
continuation of a vein beyond a cross-course or fault; n)ill-
lioles. 7. Quarrying and "getting" of salt ; hydraulic .iiining;
exploitation of peat and phospliate beds. References.
CHAPTER III.
Methods of IVIining,
8. Analysis; discussion of the general applicability of mining,
•' retreating," differences between coal and metal mining; the
least niinable thickness of deposits. 9. Overhand and unrlerhand
methods, comparison and applicability of; account of the long-
wall system ; details of the plan ; gob-roads and their care. \o.
Pill.ir and stall method of mining; dimensions of rooms and of
pillars ; creep, cave, crush, or squeeze, and their pre\eniion ;
order and manner of winning pillars; mining loss and waste.
II. Modifications of the pilhir and stall system; the "County
of Durliam ;" the " Wasmuth ;" barrier pillars ; relati\e merits
of long-wall and pillar and stall ; panel system ; " square work ;"
gallery and pillar. 12. The American system of " square sett,"
as applied to veins and beds ; modes of mining thick seams, in
slices or by filling or caving; traverses with filling or with cav-
ing. References.
CHAPTER IV.
Hoisting Machinery 59
13. Manual labor; description of windlass and winches; the
work of man ; examples ; modes of increasing the efficiency of
a windlass ; double and conical barrels. 14. Hoisting by horse
and whim; the work of a horse; examples; descriptions of
whims, derricks, pulleys, etc. ; double and conical drums.
15. Engine hoisting; conditions, etc., for selecting a machine
plant ; sectional and tubulur boilers and their care ; consump-
tion of fuel and water; anti-incrustators and economizers; im-
portance of the concentration of machinery ; distribution of
CONTENTS. XI
PAGH
power; location of hoisters ; description of the engine; cut-offs
and condensers. i6. Descriptions of types of lioisting-engines ;
first- and second-motion engines ; gearing and friction hoisters.
17. Description of the various types of friction-clutches; drums,
their sizes and construction ; the Calumet and Hecla leviathan ;
modes of equalizing the work of the engine ; conical drums,
reels, and counterpoises. References.
CHAPTER V.
Electricity and Water-power, ....... 94,
18. Application of electricity and water-power to long-dis-
tance transmission; comparison with mechanical means; uni-
versality to all operations of mining. 19. Conducting wires,
size, etc. ; two-wire and three-wire systems ; safe voltage ; expla-
nation of the electric units, and formulae ; conversion of electric
into kinetic energy by motors; efficiency of motors; storage
batteries. 20. Mode of obtaining water-power by the use of
Leffcl, Knight, and Pelton wheels ; description, efficiency, and
application of the plants and machines References.
CHAPTER VI.
Hoisting Operations 107
21. Hoisting-derricks, construction of ; essentials for strength
and safety; overwinding, and the devices for preventing the
same; indicators, and the modes of communication with the
mine. 22. Calculation of the strains in hoisting-frames; con-
structions in iron and wood ; sheaves and their importance.
23. Calculation of the hoisting-capacity of a mine or shaft;
hoisting-velocities under different conditions of timbering;
loading and unloading conveniences, formulae and examples ;
work of the engine in hoisting; definitions of horse-power,
indicated, tlieoretical, and calculated; formulae; examples.
References.
CHAPTER VII.
Hoisting Conveyances, 124.
24. Kibbles and buckets, their sizes, etc. ; objections to
buckets in hoisting; guides, etc., for rapid hoisting; skips and
gunboats for slopes ; automatic dumps and brakes. 25. Slope-
XU CONTENTS
PAGE
carriages compared with skips ; cages for vertical and inclined
shafts; single- and double-deckers; safety appliances and
clutches discussed; landing-doors, dogs, etc., for cages; ropes
of hemp, iron and steel wire, round and flat; locked wire ropes;
tapering ropes for equalizing the work of the engine. 27. The
life of a rope, its care and preservation ; splicing and testing;
cost of ropes. References.
CHAPTER VIII.
Underground Traffic, .....,,. \\\
28. Description of cars, low vs. high; investigation into the
minutiae of rolling-stock; wheels and self-oilers; gauge and
grade ; spragging ; automatic devices against runaways. 29. Life
of a car, dumping cradles, etc.; rails and turn-plates; economy of
rolling ways ; consideration of friction, grade, consumption of
power, etc. ; tramming by hand ; work of man and animal in
haulage ; mules and horses, their cost and efficiency, compared
with mechanical appliances; grades and the various limitations
to haulage powers ; objections to underground engines. 30. Lo-
comotives for underground haulage; their sizes, speed, cost,
and efficiency; smokeless, pneumatic, and electric engines;
details of gravity roads, self-acting inclined planes, engine
planes; clips, wheels, brakes. 31. Tail-rope systems, details,
size, and cost of plant; mode of passing around curves. 32. End-
less cable systems ; descriptions of the four varieties ; compari-
son of their advantages and adaptability ; report of the tail
rope committee ; exainple. References.
CHAPTER IX,
Surface Transportation 175
33. The pioneer burro; aerial tramways; description of the
Bleichert, Hallidie, and Huson types; capacity, cost, etc.; regu-
lation of the tension of the rope.. 34. Wire-rope transmission
of power; pulleys, sheaves, rope, etc., formulse. References,
CHAPTER X.
Pumping 183
35. Exclusion of water by cribbing and tubbing shafts ;
building dams and plastering cross-courses m levels; the use
CONTEXTS. XIU
I-AGE
of advance bore-holes in approaching abandoned workings;
drainage by tunnels ; co-operative drainage ; hydraulic rams and
the Hungarian system of pumping ; bailing by self-filling
bucfcets, skips, and tanks. 36. Single-acting lift-pumps; details
of sizes, of rods, pipes, valves, gaskets, etc. ; spiral weld vs.
riveted pipes ; formula; for calculating the dimensions of parts ;
cost of surface plant; descriptions of the Cook, Wormer, and
Bull pumps ; working by steam or water pressure ; formulae.
37. Single-acting force-pumps; method of altering lift- to force-
pump; description of the mechanism and operation of the
Cornish pump, size of pipe, length of lifts, and dimensions of
pump-rods; tapering rods, catches, V-bobs, and balance-bobs;
formula; for the thickness of pipes, discharge, etc. ; account of
the Ontario, Friedensville, and other mammoth plants. 38. Reg-
ulation of tlie speed of pumping; churning of the plunger,
vibration of the rod, and its prevention. 39. Double-acting
pumps, sinking pumps, Cushier system; steam-pumps; their
construction and operation ; formula? for sizes of cylinders,
discharge, etc. 40. Comparison with the Cornish pump, rela-
tive advantages of the steam plants ; pumping-engines ; com-
pound and condensing pumps, duty and calculation of ; rotary
pumps ; water-pressure engines ; California and Nevada sys-
tems ; electric pumps ; the windmill for power. References.
CHAPTER Xt.
Ventilation, .215
41. Laws regarding the ventilation of mines; output depen-
dent upon the hygienic conditions; division of the subject into
three branches ; the gases encountered in mines, carbonic acid,
sulphuretted hydrogen, carbonic oxide, and fire-damp; their
physiological effects; how evolved, where accumulated, and
how removed. 42. Treatment of asphy.xiated persons; effect of
the gases upon lamps ; modes of testing for fire-damp; Hepple-
wite-Gray tester; Shaw's apparatus; explosions; after-damp;
influence of the barometric changes upon the evolution of gas;
the sole means of obtaining security. 43. Consumption of air
by combustion, blasting, etc. ; dilution of the products of com-
bustion ; volume of air required in a mine for man, light, beast,
powder, and extent of working-face exposed; allowance neces-
sary for drag and friction ; physical laws of the movement of air.
The water-gauge, its use, and the interpretation of the different
modes of measuring air ; the ventilation paradox. References.
XIV CONTENTS.
CHAPTER XII.
PAGE
Methods of Ventilation ' . - . 235
44. Methods of ventilation of a tunnel or advancing gangway ;
by conduit or brattice; single- and double-entry, and outlet;
diagonal, or adjacent, systems for double-entry; increase of
temperature with depth; limit of the depth of mining; natural
method of ventilation by two outlets at different levels ; limita-
tions of the method by season and depth ; ventilation of railroad
tunnels ; account of the different experiments and that finally
adopted. 45. The flow of air by changes of pressure or of tem-
perature; the flow of any fluid under a change of tension;
motive Column ; formulae. 46. Methods of accelerating natural
ventilation, etc. ; furnace ventilation ; cost and construction of
the furnace; temperature and volume of the air produced;
dangers and limitations in its employment; dumb channels in
fiery mines; exliaust-steam as a ventilator. 47. Mechanical
ventilators; description of hand-fans and their adaptability;
blowers; Root fans; champion blowers; use of compressed air
as ventilator ; exhaust-fans ; details in the construction, arrange-
ment, efficiency, and cost of the same; Guibal fans; lines of
improvement; method of housing; outlets and connection;
description of the Waddle, Schielc, Lemielle, Cooke, and Fabry
fans ; comparison of iheni ; effect of a low barometer and high
temperature on the volume of the exhaust ; fan vs. furnace.
References. 48. The theory of the action of the fan ; its
equivalent orifice; its efficiency. 49. Principles of design for
fan; formulae; example. References.
CHAPTER Xin.
Distribution of the Air, ■•••.... 271
50. Calculation of the work done in ventilating a mine ; losses
by friction; coefficient of friction; formulae; examples; simi-
larity between the formulae for frictional resistances of water
air, and electricity ; examples and illustrations. 51. Interpreta-
tion of water-gauge readings; formulae; examples; Buddie's
system of splitting air-currents ; advantages and economy of the
plan ; principles of dividing air-currents into panels ; formula •
laws governing the area of airways ; dangers of goaves, and the
necessity for their isolation. 52. Velocity of the air and the
CO.VyENJ'S. XV
PACE
modes of measuring it, by candle, snir)lce, or anemometer ; place
for observation ; calculation of the ventilating power. Refer-
ences.
CHAPTER XIV.
Regulation of the Air-current, ...... 285
53. Doors, regulators, etc. ; safety doors, and extras, to be
dropped after explosion; air-crossings, overcasts, brattices, and
their use; mineralized brattice. 54. Complete example for the
ventilation of a mine, with two outlets and five splits; furnace,
fan, and natural ventilation methods compared; example and
calculation for a railroad tunnel. References.
CHAPTER XV.
Illumination, 292
55. Use and consumption of candles, etc. ; Davy's discovery
and invention; description of the safety-lamp; remarks regard-
ing later forms ; Stephenson, Mueseler, Hepplewite-Gray, and
Marsaut. 56. Requirements of a safe lamp; modes of render-
ing them secure ; candle-power of the different types ; electric
illumination. References.
CHAPTER XVI.
Hygienic Conditions 302
57. Laws upon ingress and egress; accidents in mines; lad-
ders, their arrangement and cost; loss of time and energy;
use of cages for men ; conclusions of the Cornwall Society.
58. Movable ladders or man-engines, single or double ; utiliza-
tion of the pump-rods for the purpose ; comparison of the
safety of the man-engines with other means ; cost of the
machinery and plant. 59. Accident laws for the protection of
life and limb ; are equally effective for the security of the mine ;
statistics; accident-rate decreasing; tables; lessons drawn from
their inspection; causes and prevention of accidents; fall ol
roof; lack of timbers; explosions; premature blasts; neces-
sity for a rigorous enforcement of the rules and laws. 60. Gen-
eral remarks concerning fires in mines, their causes, prevention,,
and treatment; entering old mines ; aerophones. References.
CONTENTS
PART IL
PRACTICAL MINING.
CHAPTER 1.
PAGE
Shafts, ,...,..,, 323
61. Shafts: their location, dimensions, and shape; round ?'^.
square; sump and subsidiary shafts; equipment, number, and
size of compartments ; single- and double-entry shafts or slopes :
shafts for railroad tunnels ; mode of sinking, progress, and cost.
62. Timbering shafts; various modes of cribbing by wood,
masonry, and iron; shaft pillars ; slope timbering; Hollenback
shaft; walling of circular shafts. References.
CHAPTER II.
Sinking in Running Ground 338
63. Precautions taken to exclude water ; tubbing ; description
of and estimates for Triger's method. 64. Kind and Chaudron
process of tubbing and sinking through watery strata ; descrip-
tion of the tools ; estimate of cost ; applicability and advantages;
examples; Haase's system; J. Mill's Californian method;
Poetsch's freezing process. References.
CHAPTER III.
Timbering, ......... , . , 348
65. The use and preservation of timbers ; for jointy rock,
horses, and disintegrating rock ; consumption of timbers in
mines ; selection of timbers. 66. Props, sprags. stulls, and their
plates ; formulae for strengtli and the calculation of their dimen-
sions ; variety of joints. 67. The construction of setts, frames,
etc., for various conditions of roof, walls, etc. ; timbering for
levels, gangways, gob-roads, and for support of vein, gangue,
etc.; in salt mines; lagging; wood, iron, and masonry for levels.
^68. Square setts, joints, and sizes of parts ; full account of the
CONTENTS. xvu
American method; cribs for rooms; timbering of mill-holts,
underground chambers, plats, and winzes; timber-man's tools „
framing-machines. References.
CHAPTER IV,
Drifts, Tunnels, and Adits, ;77
69. Utility, dimensions, and location , mode of driving, prog--
ress, and cost. 70. Tunnelling through hard and soft ground "
dimensions for various purposes ; difficulties in soft rock ; de-
scription and comparison of the English, Belgian, German, and
Austrian methods ; the American method ; examples of long
tunnels ; auxiliary shafts. 71. In treacherous ground ; method
of spilling by laths; by wedges; poling; Durieux's method;
iron shield and pneumatic processes; masonry for permanent
security; principles in the construction of arches and centres.
References.
CH.A.PTER V.
Boring 396
72. Punch-drills for artesian and oil wells ; history of its ad-
vancement; accounts of deep bore-holes; Fabier, Kind, and
Degousee tools; Mather and Piatt system; description of an
oil-well plant. 73. Spudding, cost, progress, accidents, etc.;
tools, rods, torpedoes, tubbing, and their recovery, where used
in preference to the diamond-drill ; novel Colorado method.
References.
CHAPTER VI.
Breaking Ground, 404
74. Notes of cost and progress , fire-setting method, descrip-
tion of. 75. Description of miners' tools; the pick and varie-
ties; underholing; shovels and spades; sledges; hammers;
plug and feather; lewising; gads and moils. 76. Hand-borers;
single and double hand-work; tools for the same; hammers,
drills, and steel; jumpers; consumption of steel, "j"] . Black-
smith's work; kind of coal to be used; brief account of the
materials employed in miners' tools; their selection and prepara-
tion for use; welding, hardening, and tempering, and how
accomplished. 78. Varieties of bits and points for different
rocks; sharpening and steeling picks, drills, etc.; making
handles and helves. References.
xvni CONTENT!,,
CHAPTER Vli.
PAOS
Blasting, ,„....,,. .423
79. Principles in rupturing soft mineral or rock; substitutes
for powder ; lirae, compressed air, and wedges ; theory of explo-
sion ; tables of comparative force of explosion. 80. Gunpowder,
Its composition, "barrel" and "needle" methods of firing;
use of, and care with, powder; tools, fuse, caps; lewising;
consumption of powder. 81. High explosives; nitro-glycerine,
its mode of manufacture; precautions. 82. Dynamite and its
modifications ; composition, etc. ; relative explosive effects of
the nitro-glycerine compounds ; their storage and care ; com-
parative safety; tools, fuse, and caps. 83. Simultaneous firing;
electricity from battery and magneto machines; difference in
the caps, fuses, and care ; manufacture of fulminates; relative
advantage as compared with smgle shots ; cost of electric outfit ;
consumption of materials ; precautions. 84. Principles; direc-
tion of holes ; line of least resistance ; formulae for calculating the
effects of shots ; influence of seams, cleats, etc. ; expanding bits.
References.
CHAPTER VIII.
Drills and Drilling . . 451
85. Channellers and quarrying machines ; cost, economy, and
use ; tools needed ; steam and pneumatic power. 86. Percussion
drills ; requisites for a good drill ; construction ; valves and im-
provements ; descriptions of the different drills in the market —
Rand, Sergeant, IngersoU, Burleigh, Schram, and Darlington.
Z"]. Rate and length of stroke in hard and soft rock; drifting,
sinking, and sloping by machine; relative cost and progress by
machine and hand labor; shapes of bits, tools, connections;
colunm 7'5. tripod. 88. Diamond-drill; description of machine ;
operation ; gear and hydraulic feed ; solid and annular bits ;
consumption of stones. 89. Rate of progress; economy, cost ;
its function as a prospector; mode of keeping its record;
Brandt's drill; electric drills; perforators and entry machines.
90. Size and depth of holes; system of arranging holes: Mt.
Cenis and St. Gothard system ; the American "centre-cut" sys-
tem. 91. Brain's radial system ; progress, cost, and ratio of
cubic foot broken to tlie foot of hole; Gen. Pleasant's method
of long-hole or continuous drilling by diamond drill. 92. Coal-
cutting machines; discussion of the types; comparison of the
work done, with hand-labor; account of the Harrison, Jeflfry,
CON TEN 'JS. XIX
Sergeant. Lincke, Winstanley, Marshall, and Friths machines
clecinc cutierb. Kelcrcuces.
CHAPTER IX.
The Compression of Air, ...,.., 490
93. Theory and principles; heating during compression;
influence of altitude; losses in the compression; equalizers and
compound cylinders ; construction of the machine and its re-
quirements ; means for rendering the resistance of the piston
uniform. 94. Calculation of the work done upon the air;
tables; formulse ; discussion of the valves and forms of the
principal air-compressors on the market; air-receivers and their
form and utility. 95. Conduction of the air; air as a motor;
pipes, expanders, etc. ; theory in the operation of the motor;
tables of losses by friction ; discussion of the economy of
working with or without expansion. References.
CHAPTER X.
Mine Examination, .510
96. Examination and evaluation of mines; sampling and
riiCasuring the deposit; features to be noted; capitalization;
"ore in sight." 97. General remarks regarding tlie treatment
of ores; factors determining their value; deleterious sub-
stances; various milling processes; cost of mining; formulae
for mine valuation. 98. The mining-labor problem ; variety of
skilled labor employed; selection of men; necessity for regu-
lations and their enforcement; conveniences, liygienic and
otherwise ; number of shifts and their length ; mode of paying;
necessity for reciprocitj' ; day's pay vs. tribute system ; contracts
and the mode of letting; pay by the output or progress; dead
work; leasing mines. 99. Retrospective. References.
■APPENDIX.
Sample Examination Questions, 526
For appUcants for the othce of mine inspector or underground
manager. Fony-four typical examples and questions taken from
foreign and domestic examination papers.
Glossary of Mining Terms . 530
With references to text and illustrations.
X^ CONTENTS,
?AGE
Signalling, .... , , ,. o S45
A code of signals, with explanation.
UsKFUL Information, ...... ^ , 545
Weights and measures : Troy and avoirdupois pounds; tons;
busliels ; board measure ; value of a miner's inch ; weights of
material for a mile of track ; equivalents of atmospheric press-
ure in air, water, and mercury; weights of columns of air and
water and of bars of iron.
Table of Weights .of Various Substances, . 547
Weights of a cubic foot of various rocks, minerals, ores, coals,
and wood.
Equivalents of French and English jVIeasures, . . . 547
For ready conversion of feet, inches, pounds, s^all'ms. linear,
square, and cubic measure, into metres, grams, and litres ; foot-
pounds and heat-units into calriric ; Fahrenheit into Centigrade
degrees , etc.
Table df Hyperbolic Logarithms, .,>,... 54S
For calculations in the expansion of gases.
Index. . , . . . . „ . . . . S49
AUTHORITIES CONSULTED OR QUOTED.
Ore Deposits. J. A. Pliillips.
Elements of Geology. ]. Le Conte.
Metallic Wealth of the Uiiited States. [. D. Whitney.
Report AC, Second Geological Survey of Pennsylvania. Dr. H. M,
Chance.
Hx'draulic Mining. Aug. ]. Bo .vie.
Mechanical Engineering ni Collieries. Percy.
Steam-engine. W. H. Northrott.
Manual for Mechanical Engineers. D. K. Clark.
Mining Engineering. G. G. A. Andre.
Lectures on Mining. C. Le Neve Foster and J. Gallon.
Coal-minmg Alaciimery. G. G. A. Andre.
LInderground Haulage. W. Hddenbrand.
Aerage des Mines. Combes.
Mine Ventilation. E. B. Wilson.
Coal-mine Explosions. W. N. Atkinson.
Mine Accidents and their Prevention. Sir F. G. AbeL
Accidents in Mines. A. F. Sau-yer.
B.uiniaierielien. R. Gottgetreu.
Bergbaukunde. Di. A. Serjo.
Leitfaden zur Bergbaukunde. Lottner.
Lehrbuch der gesaniniten Tunnelbaukunst. Rziha.
Tunnelling. H. S. Drinker.
E.xplosive Compounds. H. S. Drinker.
D. Clark.
Modern High Explosives. M. Eissler.
Submarine Mines. Col. H. L. Abbott.
Mining Glossary. R. W. Raymond.
Reports of the Ro\al Commissioners, Accidents in Mines,
Berg- und Hiittenmannische Zeitung, Vienna.
Annales des Mines.
Proceedings of the North of England Institute of Mechanical Engineers,
Transactions of the Mining Institute of Scotland.
American Institute of Mining Engineers.
Engineering and Mining Journal.
Colliery Engineer.
xxi
xxii AUTHORITIES CONSULTED OR QUOTED-
Reports of the Mining Inspectors of Pennsylvania:
" " ' ' • Ohio.
•' " '■' ■ West Virginia
" " " •' " Colorado,
•• " Bureau of Labor Statistics, Illinois,.
«... ;i « " - ■ Missouri
«• " Commissioner of Mineral Statistics ol Micnisa«
A DIRECTORY OF MANUFACTURERS REPRE-
SENTED BY THE ILLUSTRATIONS.
The following is the list of manufacturers who have con-
sented to the use of their illustrations in this book. The
numerals after their address designate the serial number of
the figure. Figures marked * are reduced copies of manu-
facturers' cuts.
Abendroth & Root Mfo;. Co., 28 Ciiff Street, N. Y. City. 19, 78.
Edward P. Allis Co., Milwaukee, Wis. 21*, 22*, 27*.
American Diamond Rock-Boring Co., 15 Cortlandt Street, N. Y. City.
241-245, 249.
Babcock & Wilco.x Co., 30 Cortlandt Street, N. Y. City. iS.
Chicago Iron-Works, Hawthorn anri Willow streets, Chicago. 20, 62,
81, 83.
Cook Well Co., 703 Market Street, St. Louis. 84-86.
F. M. Davis, Larimer and Eighth streets. Denver. 32. 50, 51,60.
Deane Steam-Pump Co., Holyoke, Mass. gr, 92, 96.
Diamond Prospecting Co., 15 North Clinton Street, Chicago. 247, 251.
Edison Electric Co., N. Y. Citv. 241.
Frazer & Ciialmers, Union and Fulton streets. Chicago. 34-39, 43,
44, 89*.
Fulton Iion-Works, 213 Fremont Street, San Francisco, i, 23*, 44-49,
65. 75. 76. 77.
Hendey & Meyer Engineering Co., Denver. 195*.
H.irrison Mining-Macliine Co., 175 Dearborn Street, Chicago. 257.
Iiigersoll Sergeant Drill Co.. 10 Park Place, N. Y. City. 24, 28*, 235,
237. 238, 255-257, 259.
Iron Bay Co., Duluth, Minn. 25, 26, 87.
Jeffry Manufacturing Co., Columbus, Ohio. 68, 258.
Knight & Co., Sutter Creek, Calif. 97*.
Knowles Steam-Pump Co., 93 Liberty Street, N. Y. Citv. 90, 94, 95.
Laflin & Rand Powder Co., 29 Murray Street, N. Y. City. 216, 217.
James Macbeth & Co., 128 Maiden Lane. N. Y. City. 215.
Norwalk Iron-Works. South Norwalk. Conn. 258, 262.
Oil-Weil Supply Co., Pittsbtirg, Pa. 212, 213.
Pelton Water-Wheel Co., 123 Main Street, San Francisco. 33.
H. K. Porter & Co., Pittsburg, Pa. 66, 67.
Rand Drill Co., 23 Park Place, N. Y. City. 3*, 5*, 115,233, 234, 240,
252, 260, 261*.
Spiral Weld Tube Co., 43 John Street, N. Y. Cily. 82, S3.
William E. Stieren, 544 Smithfield Street, Pittsburg. 98, 106-109.
Trenton Iron-Works, Trenton. N. }. 71, 72, 74.
Webster. Camp & Lane Co., Akron, Ohio. 29*.
Yale & Towne Manufacturing Co., Stamford, Conn. 30.
ABBREVIATIONS.
The following is a list of abbreviations which are used to
denote the periodicals to which references may be made for a
more extended discussion of the subject than is given in the
text. The title of the article, the name of the author, the
volume or date of the publication, and the page on which it
is found are given in the order named.
A. M. Inst. M. E. Transactions of American Institute of Mining
Engineers, 19 Burling Slip, N. Y. C.
Am. Alfr. Tl)e American Manufacturer and Iron World, Pittsburg, Pa.
Ann. lies Mines. Annales des Mines, St, Etienne.
A'r//. .Soc. JMin. Stud. British Society of Mining Students, Radstock
Colliery, Bath, Eng.
Bureau of Mines, Ontario. Reports ; Toronto, Ontario.
Lai. Slate Mill. Bureau. Report of California State Mineralogist,
Sacramento, Cal.
Cassier's Magazine. The Cassier's Magazine, World Building, N. Y. C.
Chest. Inst. Chesterfield and Midland Counties Institution nf Engineers,
15 Cavendish St., Chesterfield.
Coll. Eng. The Colliery Engineer, Scranton, Pa.
Coll. Guard. The Colliery Guardian, Strand, London, W. C.
Coll. Atgr. The Colliery Manager, Bowerie St., London, E. C.
Elec. Eng. The Electrical Engineer, 20S Broadway, N. Y. C.
Elec. World. The Electrical World, 253 Broadway, N. Y. C.
E. M. J. The Engineering and Mining Journal, 253 Broadway, N, Y. C.
E-ng. Asso. of the South. Tiie Engineers' Association of the South,
Birmingham, Ala.
Eng. Magazine. The Engineering Magazine, 120 Liberty St.. N. Y.
Eng. jXews. Engineering News, Morse Building, N. Y.
Eng. Bee. The Engineering Record, 100 William St., N. Y.
Eng. Sac. IV. Fa. Proceedings of the Engineers' Society of Western
Pa., Pittsburg, Pa.
Eed. Inst. M. E. Transactions of the Federal Institution of Mining
Engineers, Neville Hall. Newcastle-upon-Tyne, England.
Erank. Inst. Jour. Journal of the Franklin Institute, Philadelphia, Pa.
xxiv
ABBREVIA JWNS. XXV
Geology Surrey OJiio. Columbus, Ohio.
///. ISlin. Inst. Transactions of Illinois Mining Institute, Springfield,
Illinois.
Jotcr. Asso. Eiig- Soc. Journal of Association of Engineering Societies,
Chicago, 111.
L. S. Mill. Inst. Lake Superior Mining Institute. Minneapolis, Minn.
Mm. Bureau, Co/. Bureau of Mines of Colorado, Denver, Colo.
M/iieral Industry. Statistical VoiunK--.s. Scientific Publishing Co., 253
Broadway, N. Y. C.
.Mines and Minerals, Scranton, Pa.
Min. and Sci. Press. Tlie Mining and Scientific Press, San Francisco,
Cal.
Min. Bull. The Mining Bulletin of the Pennsvlvaniii State College.
Min. Inst. III. Transactions of the Illinois Mining Institute.
Min. Ind. The Mining Industry and Tradesman, Denver, Colorado.
Mine Inspec. Reports of Mining Inspectors of the Siaie named.
M.&^M.Eng. Trans. Transactions of North England Mining and
Mechanical Engineers, Newcastle upon-Tyne. I'",ni;land.
N. Staff. Inst. Proceedings of North Staffordsliiri' Institute of Mining
and Mechanical Engineers.
N. E. I. Transactions of North of England Alining and Mechanical
Engineers.
Ohio Min. Jour. Journal of Ohio Mining Institute, Columbus, Ohio.
Queensland. Report of Secretary for Mines, Queensland.
/\ev. Univ. Revue Universelle des Mines, Liege.
5 of M. Quart. The School of Mines Quarterly, Columbia University,
N. vrc.
Second Geolog. Surv. Pa. Report of Second Geological Survey of Penn-
sylvania, Harrisburg, Pa.
Scientif. Quart. The Scientific Quarterly of the Colorado School of
Mines, Golden, Colorado.
MANUAL OF MINING.
Part I.
MINING ENGINEERING.
CHAPTER I.
GEOGNOSY.
1. Bird's-eye view of the subject ; native metals, minerals, ores, and their
occurrences, definitions. 2. Vein matter, gangue, and gouge ; geog-
nosy of ore-deposits; gash and fissure veins, beds and blankets;
geological theories and miners' rules ; prejudices and fallacies regard-
ing ore-deposits. 3. Prospecting; searching for veins; indications,
float, shode. and slide rock; examining new districts; divining-rods,
spiritual mediums, and the drill as miners. 4. Remarks upon the
chaotic state of the U. S. mining laws; apex vs. side lines; safety in
the side-line law ; advice to locators; insecurity of locations on the
apex ; patenting claims.
I. The .search for the useful and precious minerals has been
dihgently prosecuted since the early days of civilization ; their
discovery and application have made nations powerful expo-
nents in the world's history. And nowhere is this fact better
exemplified than in our own land, in the wonderful openiiiLj
ind rapid settlement of the Western mining States.
No subject is more entrancing, no occupation more exhila-
rating, than mining, with its wonderful kaleidoscopic changes.
In early times excavations were made and mines worked only
to a small depth and in easy rock, and that, too, only for sub-
2 MANUAL OF MINIXG.
stances of high intrinsic value, notwithstanding the myriad?
of slaves to furnish the labor. The attempts at systematic
mining were few and far between ; but since the advent of the
steam-engine, mining has been acknowledged an important
profession, requiring technical education. Competition with
the whole world, brought about by the improved means of
communication, the paucity of bonanzas and their rapid ex-
haustion, compel a skilful utilization of all the aids to a cheap
extraction of our immense wealth.
The accessibility of the mine and the vendibility of its
product are the ever-ameliorating features in the mining history
of nations, districts, camps, and individuals, gradually divesting
mining of its risks and rendering it more and more akin to
manufacturing. Each new camp, untrammelled by tradition
to keep it in the rut of prejudice, displays its genius for organ-
ization and absorbs the latest devices, tried and true. Never-
theless, it must be admitted that in each camp an adequate
solution of the problem involves intricate questions of environ-
ment. The economy of mining is a function of many variables,
as geological stratigraphy, subterraneous uncertainties, wages,
water, timber, transportation, and treatment. The constants
arc few. The proper relation of these it is our province herein
to discuss.
Hitherto a gambling spirit has frequently controlled in-
vestments in metal mines. Speculative tendencies, not tech-
nical economies, have dominated some of our operators; their
heavy aggregate outlay may have proven unprofitable, for the
present, because of salted mines, attractive prospectuses, or
incompetent management. It must be remembered, however,
that they have contributed to the prosperity of the country,
and at some later date their abandoned exploitations will be
pursued to profit, when the potential investment of to-day will
have been resolved into future kinetic dividends, the cost of
production being continually on the decrease.
The occurrence of the useful or precious minerals in the
state of native purity is rare. Still less often are they found
superficially : they must be delved for. In the extraction of
GEOGNOSY. 3
this subterraneous material, and its delivery to the surface,
consists the art of mining. The legal definition of a mine
includes such "workings as must be artificially lighted."
Gold and platinum are found native in the placer accumu-
lations of ancient and modern river-beds, which furnish fully
75 per cent of the total output of these metals. Gold occurs
in segregated veins, alloyed with tellurium, and always asso
ciated with pyrites and titaniferous iron ; also intercalated
between the sheets of slate or sliale, or finely disseminated in
eruptive rocks. The only extensive native copper deposit is
the remarkable product of the Lake Superior region, where
the irregular masses arc mined nut of the amygdaloid trap and
sandstone. Singular masses of metallic iron ore are found in
several localities, but the}' are curiosities and casual, if not
meteoric. Native silver is rare and occurs in Peru, Mexico,
Norway, and in the Lake Superior copper mines.
With these few exceptions the metals are encountered in
chemical union with non-metallic substances, more or less
completely segregated to constitute mineral. Any accumula-
tion of mineral of good quality and in sufficient concentration
to warrant the expenditure of energy for its extraction is an
ore. Manifestly this is a fickle term, since it depends for its
stability upon the casual coiulitioiis of the market as well as
upon the mineralogical features.
The most common substance is iron, entering as it does
into almost all rocks and veins. Its most frequent, and value-
less, combination is with sulphur. Magnetic and specular
oxide and the carbonate constitute the entire supply. These
occur as irregular masses in the rocks of every geological age,
or in veins mixed with other minerals, but are chiefly in the
metamorphic crystalline, Archaean rocks. Zinc is obtained from
calamine, franklinite, and blende, which are quite extensively
distributed in the Carboniferous strata. With very few excep-
tions, galena is exclusively the ore of lead. The carbonate and
the sulphide, in the lower Silurian and Carboniferous strata,
mostly occur in irregular shoots and pockets, and rarely argen-
tiferous. In the older metamorphic rocks the galena is con-
4 MANUAL OF MININC.
fined in fissure veins carrying silver and gold. The nr.ain
supply of silver is from its minerals, more or less intimately
associated with other ores. Similarly with them, it has a wide
geological distribution, and is also found " dry" in fissures.
Copper, as chalcopyrite, bornite, and cuprite, is disseminated
in and along slates and sandstones, rarely above the Triassic.
Many galena veins in the metamorphic rocks change with
depth to copper. Mercury comes from cinnabar, which is
found in true veins and in contacts. It is not commonly
encountered. Tin has a characteristic occurrence in but one
form, as an oxide, and only in gash or segregated veins, or
"stockwerke" of the older rocks.
Tin lodes are of the segregated type, and gold or silver
bearing, pyrites and cassiterite being the common minerals.
Millerite and pyrrhotite are nickeliferous and occur in gash
and segregated veins, rarely deeper than 500 feet. Rich films
of genthite in talc veins often constitute a commercial supply.
Manganese ores (standard contains 44 per cent of the metal)
are generally associated with limonite and occur in pockets
usually embedded in clay as contacts or beds or permeating
slates. Films of manganese appearing in moss-like forms on
the face of rock give it the name of " landscape" rock.
Mica is generally in bedded veins, instances of contacts and
true lodes being rare. They are simply and always dikes in
coarse granite. Hitherto only large slabs were sought, but
now the fine, clean mica has a ready sale for lubrication and
other purposes.
Phosphate rocks for fertilizers, the practical value of which
is determined by the amount of phosphoric acid contained, are
found as beds of irregular thickness ; veins or lodes transversely
to the strike of the strata ; or superficial deposits. Apatite
occurs concretionary in a clay matrix between limestone and
;lay. These are more frequent in the Miocene.
Many of the metals are incidentally obtained from their
mineral compounds while smelting for other metals with which
they are associated.
The metalliferous portion of a lode usuall)' comprises only
GEOGNOSY. 5
a small portion of its contents. The argentiferous galena,
bornite, blende, or thei; oxidized derivatives in grains, pockets,
or streaks, more or less connected, are associated with a
"gangue" of cla}-, quartz, fluor, calc, or heavy spar. These
earthy materials sometimes are intimately mixed with the
mineral, and again lie in layers contiguous with it, or the
different constituents may even manifest a ribbon-banded
structure.
The entire mass, metalliferous and earthy, constitutes a
deposit which is known as a bed or a vein, and may exist under
such circumstances as to render it workable. The term vein
is intended to describe a regular unstratified deposit in a fissure
that traverses the country for a considerable distance, longi-
tudinally and vertically. The Supreme Court has defined it
as " any zone or belt of mineralized rock lying within boun-
daries clearly separating it from the surrounding rock." This
demands a well-defined crevice of ready identification, and two
solid walls to give it individuality. Its lead must be metallif-
erous. A vein is the filling of a pre-existing fissure. The term
has lost the significance it once had. The mineral system was
originally supposed to have a resemblance to the human cir-
culatory system. True, the fissures have originated during
periods of great dynamic movement, producing folds and fis-
sures which are supposed to have extended deep into the earth's
crust, but the main artery has yet to be located. Though
argentiferous lead veins are quite persistent, no evidence exists
■for the dogma, so tenaciously held, that they increase in rich-
ness with depth. They may or may not become richer, or
change, in constituents. Examples can be cited for either side
of the argument. In folded strata the deposit inclines to be
thicker at the ridges, or t.'oughs, and thinner at the sides of
the folds. BLit this is not generally the case in massive rocks.
Usually thv- vein matter is crystalline. It is commonly
separated on either or both walls from the surrounding rock
by a sheet of clay (called " selvage" or "gouge"), or by other
quite distinct lines of demarcation. The surface of contact of
the deposit with the adjacent rock is called a wall, roof, or
b MANUAL OF MINING.
Hoor, according to its relative position to the miner. Not
infrequently the walls are polished surfaces (" slickensides"),
due to grniding caused by the slips during nature's contortions.
Sometimes portions of the vein have slid on one another, caus-
ing " false walls" ; therefore the miner is advised to occasionally
break into the walls to assure himself as to the fact. On the
other hand, a vein may have only one or even no wall. In the
process of mineralization, the original face or faces of the
fissure may have become disintegrated, and all evidences of
the looked-for wall obliterated. In such cases, economic, not
geologic, or legal conditions define the vein.
2. Fissures belong to regions of metamorphic action, and
are the principal repositories of the precious metals. And it
is a striking fact that they are rarely found singly, rather in
groups of parallel veins, often in congeries. Stockwerkc is a
term used to describe a condition of affairs in which the coun-
try rock is creviced in all directions, so that the whole mass
must be mined out. Some are filled with eruptive matter,
others with vein matter, still others were subsequently closed
without any deposition. The mineral components are mark-
edly dissimilar, and indicate different sources. Those filled
with the same variety of mineral were doubtless produced by
contemporaneous forces. Those fissures which interrupt the
continuity of the older veins are called cross-courses. The
manner in which the intersections occur determines their
relative age. Their absolute age is not ascertained, unless in
stratified rock. Drags are more common than is supposed,
and should not be confused with intersections. The latter
are usually richer, the former not necessarily so, at the point of
juncture. Many of the older veins are broken and displaced
by faults. Not only do veins "pinch and shoot," but the pay
streak will vary in thickness, plunge from wall to wall, or split
up into numerous feeders and ramifications, and even disappear
in a thread.
Gash veins hold a subordinate position to fissures. But
the)' are of small extent, and are usually confined to a single
member of the formation in which they occur. Their habitat
GEOCNOS Y. 7
is unmetamorphosed sedimentary rock. They have no distinct
walls or gouge, and are unreliable.
The most important sources of the mineral wealtii are the
metalliferous deposits which occur in the sedimentary strata,
and are termed beds. While the geologists may classify
them, the group is sufficiently identified by this term for min-^
ing purposes. It includes deposits, somewhat irregular in
dimensions, occurring in the transverse joints of the rocks ; as
cementing material to the remnants of shattered or insoluble
rock; as layers conformable with the strata; as isolated im-
pregnations of grains or bunches in porous rock ; or as a
metasomatic replacement of porous rock. The}- may be found
similar to fissures in a certain formation, then as a blanket
contact parallel to the stratification, to again plunge into a
lower series of rocks like a fissure, or branch out into a cham-
ber. Tliey are more easily mined, but are less persistent in
depth, than veins. Their mineral contents are very compact,
seldom crystalline, and the ganguc hardly distinguishable from
the country rock. The mineral is more or less concentrated
along certain lines called " ore-shoots," which probabl}' consti-
tuted the channels of communication with the ultimate source.
The same is also true of veins.
Irrespective of any theory, one requisite condition for
deposition is a crevice, a porous or soluble rock conduit for the
fluid from which local action has precipitated the mineral.
Open cavities were not necessarily pre-existing, for a vesicular
rock would allow of an eas\' flow to the magma, or it might be
equally well secured by dissolving action on the rock and a
subsequent replacement. This is independent of its geologic
position. In every age are rocks which will satisfy this condi-
tion. Besides this, a long train of circumstances has preceded
the vein-formation involving dynamic agencies, heat and meta-
morphism, and even eruptive action, as important factors.
These disturbances having been often repeated through the
different ages, the older rocks were more frequently shaken
up. Beyond this no reason exists for the jirejudice which
favors certain geological formations as ore-bearing.
•8 MANUAL OF MINING.
The geognostical relations between veins and their contents
are of importance to the mining engineer, but our limited
space will not admit of any discussion here. The various
works on geology will supply the information as to the vagarie?
manifested by ore occurrences and the numerous theories held
Some isolated examples exist under such circumstances as ti
suggest the same origin for the ore as for the adjoining rock-
formations. Many of the beds and veins have been impreg-
nated by percolating waters, perhaps at high pressure and
temperature, contemporaneously with the country rock. Their
metallic contents may have been carried in solution or they
may have been in a molten or a gaseous state when the way
for their passage was opened.
This is a matter for conjecture, as is also the ultimate
source of the mineral. Certainly the evidences point to its
deposition as a sulphide, the oxidized forms being accounted
for by long-continued action of atmospheric agencies. The
presence of coal and bitumen in many lead and zinc veins and
beds in a measure suggests a theory of cause. The "water-
line" theory has served its day and is no longer tenable. The
current theories have, for hundreds of years, afforded satisfac-
tory explanation of the genesis of some of our ore-deposits.
But when we find contiguous depositions contrasting widely in
point of density: narrower parts of fissures filled by larger
deposits or richer ores; superior minerals higher up than the
more volatile or lighter ones, even alternating with them, we
must admit that since the daj' Job declared that " silver is in
veins," little material progress has been made by our geologists
beyond the slow garnering of facts which, ultimately, are hy-
pothecated. Our knowledge upon this branch is cumulative
and in expression conservative. However, any theory explains
some, but none all, of the capricious examples of lodes or their
anomalous fillings. The veins we find, but not always the
silver; and this inability to formulate a general law by which
to locate the hidden bonanzas has led to the compounding of
the numerous witcheries, and divining-rods of every conceivable
form, for imposing upon the credulity of the prospector who
GEOGjVOSY. 9
seeks a quicker means of acquirement than is afforded by the
use of the pick, shovel, and patience.
There is no particular angle of dip or bearing of trend that
is universally favorable to rich veins. Rules based upon such
observations are local only. The same may be said as to the
supposed " live"-ness of certain rocks to mineral. Attempts to
formulate indications of " quickening" mineral by associations
with certain gangue matter or minerals have failed of general-
ization. The mineral is where you find it. The Cornishmaii's
adage, " riding a zinc horse to fortune," has no verity in this
country. Each locality has its own peculiarities of mineral-
ization, which the careful and systematic engineer will observe
and regard.
3. With the two classes of rocks, stratified and massive,
are coexistent the two classes of mineral deposits, beds and
veins. Though many occurrences are of a nature that admits
of question as to classification, for mining purposes a sharp
line of distinction is not sought. Legal technicalities have so
confused the definitions of deposits and veins as to obliterate
all semblance to the original intent of geologists and mining
men. Of this, more later. At present we shall consider
some rules to assist the prospector in his search for mineral.
And while it must be admitted that many a find has been
made through accident, the existence of the ore would be
found not to be at variance with the cumulative rules of geo-
logic science.
Accordingly, the prospector will seek within geological
confines. In regions of stratified rock the matter is simple.
Coal is found in three geological horizons, and the presence
or absence of the rocks belonging thereto is indicative of tlie
prospects.
The metals and their minerals are distributed, geologically
and geographically, over a large extent. The zinc ores in this
country occur in the Carboniferous and along the Mississippi
valley. The Archaean and Silurian are most prolific of the
other ores. The precious metals are chiefly found in the
mountainous districts, because the phenomena attendant upon
lO MANUAL OF MINING.
their iormation were conducive to the filhng of veins, and the
forces which gave character to the mountain also impressed
themselves upon the vein, which is exposed to view and sub-
ject to location. Without some such providential occurrences
to change the m niotonous topography of the preadamic sur-
face, bedded veins of the stratified districts would have been
revealed only by boring, while those in massive rocks might
never have been formed.
Surface prospecting is confined, therefore, to the seeking
for an outcrop. In igneous rock the outcrop is easily found.
For, unless the hill is covered with slide rock, it is indicated
by a jutting ledge (if the vein matter is harder than the
country rock), or by a sag (if it is decomposable). In heavy
timber this may go unnoticed. At high altitudes snow in the
sags calls attention to the leads.
The same is true of coal, which is located by the terraces
which mark the outcrop. The trend of the terrace, relative to
the topography of the hill, gives a good idea of the slope of
the coal. The bench itself may give the desired information,
but usually it will be found that the coal dips with the hill,
when the terrace or depression deflects outward toward the
bottom of the hill, and the reverse for a coal dipping inward,
when the outcrop will be concaved toward its top.
Substances foreign to the rock deserve notice. Alterna-
tions in the color of the slide rock covering the hill are good
indications of the presence of oxidizable minerals above. So,
too, vegetation is a guide. Iron springs often accompany the
outcrop of coal ; the ochreous covering of the rocks and soil
is noticeable near some of the anthracite seams, and is com-
mon in the semi-bituminous districts. Masses of highly
oxidized matter, broken from the veins, compose what are
called " blow-outs," and are common in galena regions.
If no evidences of outcrop are thus found, " boomincr "
may disclose it. During winter or a wet season, snow or water
is collected in a reservoir upon the hill, and, at a convenient
time, turned loose to plough its way over the soil in its fall.
Many a vein has been thus discovered without great expense.
GEOGNOSY. II
In Stratified regions the order of the geological series may
be observed, and certain fossils furnish the guide. Or, if the
prospector is examining new ground, he has but to look for
mineral in the float on the surface or in creek-bed. The
appearance of material derived from erosion is indicative of
the character of the rock from regions higher up. Therefore
the bed of the stream, or the hill slope, is minutelj' examincLl
for fragments of ore, or blossom, and followed as long as
mineral is found. If the float or shode boulders are pebbly or
rounded, or in vegetable soil, they have come from afar and
the lode is not at hand. If the shode is large and angular, it
has not come very far, and the discovery of a point be3'ond
which no float or blossom is detected is presumptive evidence
of approach to the vein. The lode will be found above the
point of discovery, and the prospector will go in the direction
of the drainage and thoroughly search the ground.
In high altitudes the oxidation of the minerals in, and the
electric manifestations of, the vein outcrops have assisted the
prospector by the light playing over them. This is of con-
tinued occurrence in Colorado above timber line, and particu-
larly in regions of arsenical veins.
When found, the vein should be examined, and its value
confirmed at several points ; most monstrous disappointments
have ensued from testing of the lode at one point only. If
the country is stratified, care is taken to ascertain all the data
of thickness, etc. Frequently the ore oxidizes and rots away,
to be crushed by the overlying strata showing on!}- in a small
streak. Or the outcrop may fold back, " tail out," and give
false impressions of great thickness.
Maps are serviceable as showing the important features, and
a systematic plotting of all data, geological and otherwise, gives
a good basis for conclusions. Dr. H. M. Chance, in the Second
Geological Survey of Pennsylvania, has an admirable discussion
on the construction of geological cross-sections, to which the
reader is referred. Prospecting for oil or gas is speculative,
and the sole guide is the geologist's facts. Reports I^ and J
12 MANUAL OF MINING.
of the Geological Survey of Pennsylvania, the Treatise on
Petroleum by Benj. J. Crew, and the report by S. F. Peck-
ham to the Census Bureau are monographs on the subject.
If surface examination fail to give a trace of mineral
sought, and there remains reasonable expectation of finding
it, a tunnel, a shaft or boring may be resorted to. The two
former are more expensive but safer guides than that offered
by boring. Shafting is slower and more costly than tunnel-
ling, but more quickly reaches a flat seam at a point suitable
for development. The steep pitching vein is perhaps best
reached by a tunnel, if the depth of vein so gained is great
enough to compensate for the length of tunnel. The choice
between them depends upon local conditions. Both are
•advisable for shallow explorations, while drilling may be
emplo3'-ed for deep work. The latter is very commonly
employed on account of its cheapness. But even when it has
■determined the data, previously doubtful, the shaft or tunnel
has to be subsequently driven. So drilling has its limitation
of use. It is rarely employed as a seeker for mineral, but
merely to give confirmation to, and assist in a rational estimate
of, the value of the undertaking. Man}' properties owe their
rehabilitation to the results of the diamond-drill exploitation,
and none should be abandoned until after a careful surface
examination had been made and followed by numerous bore-
holes.
Either the punch (72) or the diamond-drill (88j method
may be used for the boring. The former is cheaper, but
the pulverulent material brought up by the sludger is
unsatisfactory; it may indicate the constituents of the
rocks pierced at different depths, but can give little of
its physical character or dip. The diamond-drill core gives
a little more information, but even its indications are
hardly trustworthy. It affords an opportunity to identify
the rock, but some of the soft strata is worn away and
the core may be turned in its tube, so its revelations
are not much better than those of the sand of the punch-
drill, which is faster. The smaller diameter of the
GEOGNOSY. 13
hole of either renders its results doubtful ; for it may have
just missed the mineral, or have struck a solitary, small, soft
chunk of ore, which would supply cuttings to discolor the
sands for a long distance and give amazing report. Very
important deductions cannot be based solely upon the indica-
tions of the borings. Only after numerous holes and a satis-
factory surface examination can a conclusion be reached.
Good, hard common-sense, observation and pluck win,
and they alone. There is no mystery about the finding of
mineral. Nature is bountifully supplied with precious metals
and valuable minerals, but her secrets are hid. Only the
cumulative information of geological experience gives an)- clue
as to the habitat. Neither witchery nor magic charm can
hasten the knowledge of the whereabouts of an ore body or
deposit.
The wizard with the hazel wand, or the spirit medium who
is controlled by some disembodied Comanche chief, is an
impostor. No sooner is he thus equipped than he affects
a versatility and occcult power that transcends combined
scientific knowledge. Nevertheless, to a paltry amount of
" filthy lucre" he is not averse, when he plays upon the credu-
lity of natures which are duped to making extensive explora-
tions upon the purported previsions. This would be ludi-
crous, were it not also painful, to see the number of misguided
men who have squandered hopes and possessions in their
search for a short-cut to wealth.
4. The discovery of mineral at the surface must be fol-
lowed up to prove the existence of a lode or vein. The exist-
ance of an ore-deposit is a stratigraphical fact which is demon-
strable, and the granting of mining rights under the law is
accorded upon this proof. The General Land Office of the
United States and the courts decreed that a single shaft does
not necessarily carry evidence upon this point. Besides the
exposure of an outcrop or an apex on the surface, the exist-
ance of a mineralized vein, or of rock in place underneath, is
an essential feature. If the ore-body underneath is not a vein,
then the concurrence of mineral at the surface is not a part of
14 MANUAL OF MINING.
a vein. The vein may have become disintegrated ; but if the
general features still prevail — a crevice carrying mineral mat-
ter between rock of a nature and origin different from it — a
valid location may be made thereon. If, however, the vein
matter has been transported by the elements and become
mingled with other rock, it has lost all identity with its lode.
The number of legal definitions of veins is equal to tiie num-
ber of judges who have passed upon the cases. But as the U.
S. statutes divide mineral ground into veins and placers only,
the presumption would be that any well-defined metalliferous
crevice, capable of ready identification by the miner, is a vein,
whether fissure or not, — only it cannot be a placer.
The difference in the grants under the two cases, besides a
question of acreage, is that the mining of ore within placer
ground is confined to the vertical planes through the boun-
daries (sec. 2329, U. S. Rev. Statutes), while vein deposits may
be pursued along their dip, " throughout the entire depth," even
if they " so far depart from the perpendicular" " as to extend
outside of the vertical side lines of the claim ; " and the extent
of the miner's right is determined only b\- the vertical planes
through the end lines, which should therefore be properly drawn.
Locations 1500 feet in length are permitted upon the
public domain to the discoverer of the lode. But for access
thereto, and for convenience of working, the U.S. grants, as
incident to the principal feature, surface ground which,
measured from the middle of the vein, shall not exceed 300
feet on either side. Some States have reduced this to 1 50 feet
on each side, while in some Colorado counties only 25 feet
was. and 75 is, the outside limit. The claim must be essen-
tially a parallelogram. It may be 1500 feet, or less, in length,
located substantially along the middle of the apex, across
which are drawn two parallel end lines and side boundaries,
within the limit prescribed, parallel in pairs following the con-
tortions of the outcrop. However else the Act maybe vague,
it certainly is not upon the fact of the parallelism of the
exterior boundaries. Excessive locations are valid as to the
legal limit and void as to the excess.
GEOGNOSY. 15
It is incumbent upon the locator to define the boundaries
of his claim, by placing stakes at all corners and intersections,
to notify others that the ground is entered upon and being
exploited. These, with the filing of a location certificate in
the county, maintain possessory right from the moment of
posting a location notice of discovery upon the lode. Within
a reasonable time thereafter, sixty days usually, the locator is
required to sink a " discovery " shaft at least 10 feet into the
vein. This satisfies the regulations regarding discovery, and
maintains a mining right against all comers until the expira-
tion of the calendar year.
From that time on, an "assessment" of $100 must be
expended annually as evidence of mining intent. A failure to
expend such sum constitutes a forfeiture by which the claim
reverts to the public domain, and is subject to relocation. As
the value of assessment work is a matter of opinion and not
easily proven, it is safer to each year file an " afifidavit of
labor," certifying to the assessment work for that year having
been performed.
A prospector is not confined to a single entry upon a dis-
covered lode. He may appropriate as many claims as he
chooses, contiguous or otherwise, with that of the first dis-
covery. Upon each 1500 feet, or less, of length he must show
the intent to mine, by a discovery shaft and the assessment
work.
For the development of the mine, the annual assessment
work ma)' be done upon the surface or upon the vein, and all
efforts outside of the limits of the location with a bona-fide
intent to work the claim are justly considered as if upon the
claim — as, for instance, development by tunnel instead of shaft.
This concession is further extended by the U. S. Supreme
Court ; for where one person owns several contiguous claims,
capable of being advantageously worked together, one general
system of development may be adopted, after the discovery
shafts are driven. This encourages more economic work and
subserves the best interests of all concerned.
The principle having been fixed, it is not remarkable that.
l6 MANUAL OF MINING.
further concession was granted. " Where many claims are con-
solidated in the hands of one company, there is no impropriety
in calling it one mining claim." This rule, adopted by the
U. S. General Land Ofifice, solves many harassing questions,
but is more prodigal with the public mineral lands than was
contemplated by the framers of the mining code.
When, therefore, a vein or rock in place is discovered on
the public domain, it may be located on and operated. When
the locator has demonstrated his ability to develop the min-
eral resources of his claim by the expenditure of at least $500,
he may proceed to the purchasing of the land from the United
States, i.e., " patenting" his claim. Certain preliminaries are
necessary : a survey approved by the U. S. Surveyor-General
for the State ; notification to the public, by descriptive notices
posted on the claim, in the U. S. Land Office, and published in
the nearest newspaper for a period of sixty days ; affidavits of
citizenship and of the execution of the preliminaries ; abstracts
of title, and the payment for the land at $5 per acre or fraction.
An exclusive right of enjoyment " of all veins " cropping
inside of the boundaries is given with the claim. These ancil-
lary veins and their contents, to any depth whatsoever, cannot
become the property of another, even if they are discovered
and entered upon in adjacent territory. The subsequent
locator, according to the laws of the State of Colorado, may
have right of way through the cross-vein to his ground on the
other side of the prior claim, but none of the mineral. In
every case it is intended that priority shall govern. Sec. 2326
grants to the senior locator the mineral at the intersection,
and to the junior the right of way through it.
By the interpretation of the U. S. Statutes, easement and
title were clearly intended to be conveyed for all forms of
metalliferous deposits, in the use of the terms " veins, lodes, or
rock in place." The Act recognizes any mineralized rock in
place, enclosed in the general mass of the mountain, as a vein.
The arbitrary classification by geologists into veins, beds, and
irregular deposits is unimportant in relation to this matter.
Whatever the theory of vein-formation may be, it is positive
GEOGNOSY. 17
that crevices were formed during certain convulsions of nature ;
in these ore-deposition may have occurred simultaneously
with, or subsequently to, the fissuring, giving rise to various
forms of veins. The dynamic disturbance and the atmospheric
agencies that followed still further modified the geological
and topographical features of the country. The processes
were more or less similar, but the results are distinguished b}-
geologists by the terms of beds, blankets, fissures, veins of
impregnation, of infiltration and contacts. The legal expert
has confused these terms.
The Statutes favored the miner and assumed to cover all
lodes whose indications were sufficiently marked for the miner
to continue explorations thereon. A crevice, crevice matter,
a fair wall, and mineral are the essential conditions.
The discovery in Leadville of an outcropping bed, to
which a few lucky prospectors were entitled, was followed by
the promulgation of a " side-line " theory, the common law of
Leadville, Colo.
It has been seen that a lode claim, whether patented or
not, carries with it all that is beneath the surface-ground
claimed, with a servitude upon the .idjoining territorj' obtain-
ing the right of following the dip of the vein, and subject to a
like easement granted to the locator on adiacent ground to
pursue his vein wherever it may go. This obtains until some
one can show a better right. The common l.'nv as to realty is
modified when applied to mining property.
It has, however, happened that rulings were so made and
construed that a party may locate vacant "round and main-
tain ownership to the inineral covered by it, unless // is shown
thai the inineral body belongs to a lode cropping elseivherc zvithin
legally claimed ground. The proprietor who calmly continued
work upon his discovery found himself breaking into the sub
terraneous workings of others who had stolen a march on
him. To secure his right he must bring action to eject. To
vindicate his title he must prove the lode is in place and contin-
uous from the point of his discovery to, into, and through the
l8 MANUAL OF MINING.
ground of the trespasser. Failing to do wiiich, his claim is
defeated and all incidents thereto attached fail.
Naturally the train of reasoning led farther and farther
away from the original intent of the law to reward the dis-
coverer of an apex, until the accepted idea is that, although
the " defendant's location may appear to you to be along the
line of the top, apex, or outcrop of the vein, it cannot prevail
against a senior location on the dip" of the lode.
Again, Judge Hallet makes this observation, which, unfor-
tunately, has not been passed upon by the Supreme Court :
" 1 will say to the counsel in that case [a location made on
the middle part of a lode, or otherwise than at the top or
apex], which is not for the consideration of the jury, that it
has always been a question in my mind whether a location on
the dip of a vein would not be valid as against one of later
date higher up. That is to say, whether if a location be made
upon the dip of a vein, the locator may not pursue it in a
downward course, although he may not in the upward course,
and may not hold the whole which lies within his location and
below it, as against any one locating subsequently at a higher
point on the same vein."
A lack of development at the time of hearing in court, a
lack of other proof of the "perfect continuity " of the vein
from apex to side line, or one imperfect wall, invalidates the
title of apex claimant to a lode claim, and the deposit is con-
demned to be a placer, on tlie doctrine that the law recognizes
no presumption in favor of the existence of a vein, but treats
each local aggregation of ore as a separate lode. The decree
of "no lode" cuts off the privilege, nay, right, to pursuit along
the dip, and permits extraction only within the boundaries of
the claim.
To what absurdities the law has led us, by reason of the
vagarious interpretations, the reader may learn by referring to
Dr. R. W. R. Raymond's articles in the Trans, of American
Institute of Mining Engineers, or to those of the author in the
.Annual Reports of the Colorado State School of Mines.
The only remedy is to repeal the present enactment, or
GEOGNOSY. 19
else so prescribe and define the subjects of the U. S. grant,
that a purchaser shall have a warranty title to the entry. At
present he has possessory right only, and this state of affairs
Mill continue just so long as the present system attempts to
convey a right to mineral apart from that to the soil.
It has come to be accepted that litigation is one of the
regular and inevitable stages in the development of a mine —
the fruit of a strike. Justice W. E. Church, in a concluding
and conclusive sentence of a decision said: " The present laws
are a hot-bed of litigation and a fruitful source of error"
Judge Bradley declared them " imperfect," and those who
have had any experience will say " Amen."
The following references are quoted :
Amer. Insi. M. E.: The New Mining Code of Mexico, Rich. E. Chism,
XIV. 34; A Century of Mining and Metallurgy in the United States,
Abram S. Hewitt, V. 164; The World's Product of Silver, R. W. Ray-
mond, IV. 186; The Construction of Geological Cross Sections, H. Mar-
tin Chance, IX. 402 ; The Divining Rod, Rossiter W. Raymond, XI. 41 1 ;
Mining Titles on Spanish Grants in the United States, R. W. Raymond,
XXV. S44 ; Construction and Use of Topographic Models, A. E. Lehman
XIV. 439; Relief Maps, J. H. & E. B. HaVden, XVI. 279.
E. &-= M. Jour. : Australian Mining Laws, T. A. Rickard, LVIII.441 ;
Ancient Coal Mining, LXl. 160; Method of making Mme Models. W.
I. Evans, LVIII. 293.
Milling IhilU-tiii : Chronology of Coal Industry, H. H. Stock, HI.,
No. 3, 1897.
Afineral Iiuiustry : Chronology of the Gold and Silver Industry,
1442-1892, W. R. Ingalls, 1. 225.
School of Mines Quartcrlv : The Right of Lateial Pursuit, W. P.
Butler. VII.. No. 4, 357.
Cal. State Mineralogist : .\ Dissertation upon the Origin. Develop-
ment, and Establishment of .American Mining Law, A. H. Ricketts, nth
Rep. 521.
Fed. Inst. M. E. : The Formation of the Eartli's Crust and its De-
struction, Henry Aitken, VI. and VII.; Geology, Mining, and Economic
Uses of Fuller's Earth. A. C. G. Cameron, VI. and VII.
Milling Ind.: .\ncient Mining, H. F. Campbell, July 1896, 618;
Ancient Mining, H. F. Campbell, June 1896, 601.
Coll. Guard.: Ancient Mining, 1. B. Simpson, Dec. 1896, 1074;
Annals of Coal Mining in England, R. L. Galloway, Serial, LXXL, 967
to 1201 ; Laws as to the Ownership of Mining Property, judicial deci-
sion. April 1897, 734; The Mining Law of Foreign Countries, editorial
review, Dec. 1896, 1203, The Mining Law of United States, editorial
review, (uly 1897, 59; Annals of Coal Mining and the Coal Trade, R. L.
(jall'uvav. 1897, Serial Vol. LXXTII ; Right to Lateral Support, editorial
review, LXXIII. 1133; Right to Vertical Support, editorial review,
LXXIII. 249.
Coll. Minia^i;.: Ancient Coal Mining in England, Jan. 1895, 2.
CHAPTER II.
PREPARATORY AND EXPLORATORY WORK.
5. Discussion of the means of reaching veins by shafts, slopes, tunnels,
and adits; conditions and comparative advantages; dimensions of
the entries. 6. Levels, drifts, and gangways ; necessity for, and
positions of, reserves ; size of lifts and stopes ; ratio of dead work to
sloping ground ; dimensions and extent of gangways ; cleats and
their influence ; mode of finding the continuation of a vein beyond a
cross-course or fault; mill-holes. 7. Quarrying and "getting" of
salt; hydraulic mining; exploitation of peat and phosphate beds.
5. Assuming that the question, " Can the deposit be worked
with profit," has been answered in the affirmative, the following
features are next considered :
1st. Preparatory works — shafts, tunnels, and drifts.
2d. Exploitation.
3d. Plant organized for hoisting, pumping, ventilation, and
treatment.
The means of reaching veins are by shafts or slopes, or by
adit or cross-cut, the determinative factors in the choice being
local or casual conditions. A blanket vein, without outcrop,
is reached only by vertical shaft. But, as most veins crop
to daylight, the choice of a mode of access is governed by the
engineer's geological knowledge and the system of mining to
be selected. Metalliferous veins present the greatest difficul
ties, because of their uncertainties and irregularities, and at
the outset the problem of selecting an entry site is not simple,
demanding as it does the best judgment of the engineer
The entry should be centrally located near the rich ore-body,
and in the best position for drainage and underground haulage.
Often several entries are operated when the danger of caving
may require a hasty removal of mineral. Generally, how-
20
PREPARATORY AND EXPLORATORY WORK. 21
ever, a mine is planned for a long run, hence its treatment dif-
fers from that of a short lease. Much of the success of a mine
depends upon the location of the entry-mouth. Concentra-
tion of the plant and ample dumping room must be obtained,
and boggy ground shunned for foundations.
Wherever practicable, drifting on the vein by adit is fa-
vored. The first cost may be, the running expenses certainly
are, less than by slope or shaft, and the cost of equipment is
nil. Occasionally the outcrop of the vein may extend along
the hill-slope under such conditions that a series of adits may
be driven at convenient distances to explore the vein, and at
the same time develop it. But such cases are rare. Each
adit then serves for haulage and drainage of its own block of
ground. It is then of the customary dimensions and grade.
Cross-cut tunnels have some of the advantages of adits, but
more disadvantages. They are run from the steepest part of
the hill and the lowest available point, through the country
rock, to the vein. They favorably attract capitalists because
they serve to prospect and to drain a considerable field and fur-
nish a cheap, secure permanent way. Instances of successful
development by this means are few, while the many failures or
disappointments are not encouraging; for the vein ma_\' be [)oor
and split where it is reached; its grade may be ciianged with
depth or it may be dislocated by a fault, and thus the lode is not
disclosed or recognized. And this discovery made after several
years of dead work, has discouraged man}' operators and frus-
trated the development of many promising veins. After a vein
has been opened and its value demonstrated, a cross-cut is jus-
tifiable, and may yield large profit on the outlay. Obviousl)-,
the size will depend upon the service. Ample double track-
way is obtained from a 7'Xio'. Man)- large tunnels serve as
haulage canals. Undoubtedly they arc a commercial success,
but they involve a schem.e too elaborate for the individual.
Dozens are over two miles in length.
A vertical shaft may be sunk in the country rock to intersect
the vein at a certain depth. But the irregularities of lodes
and their eccentricities of pitch make this method as uncertain
22 MANUAL OF MINING.
as the tunnel. If the shaft fails to disclose the vein at the ex-
pected depth, considerable prospecting is entailed to find the
lode. Even when the vein is pierced, cross-cuts at stated in-
tervals in depth must be drifted from the shaft to the vein.
This variety of dead work is very expensive ; and should the
vein have reversed its pitch, the expense may become a serious
item, and the length of the cross-cut required to reach the
vein may become unprofitable and deter most operators at
the outset. And well it may. It is slower and more laborious
than tunnelling, but develops a more economic system and
promises surer results unless the mine is very wet. The shaft
is safer on the foot-wall than on the hanging side of the lode^
but may not always be so advised, for each lower cross-cut is
longer than its predecessor, and in hard rock and a vein not
steep its cost may soon be prohibitory. Of course these
cross-cuts lengthen as the shaft deepens, but the matter of
driving is now so quickly done as to cost comparatix'ely little.
So this is of minor importance to what it once \\'as. On the
other hand, instances of recent wrecks and abandonment from
the caving in of hanging-wall shafts are common.
In conjunction with this great outlay is the uncertainty of
the continuity of the lode. This may be obviated by sinking
on the vein. Inclines are in favcr for many reasons. Follow-
ing its contortions, they explore the vein, and more or less pay
their way. Though the cost of maintenance is much higher
than shafts, these slopes are preferred in coal regions where
the dip is over iO° and the depth not over 500 feet.
When the vein has frequent enlargements, becomes tortu-
ous and even knuckles, or if a fault is encountered, the pursuit
becomes awkward. The question then arises as to whether it
is advisable to continue the dip, follow the sinuosities of the
vein, or begin anew ; but the conditions under which it is not
advisable to sink a new shaft entirely are very few.
The author favors the plan of sinking on the vein until its
value has been demonstrated, after which the slope may be rele-
gated to sudsidiary purposes as a second outlet, for escape or
ventilation. If, however, the operators prefer to risk the outlay
PREPARATORY AND EXPLORATORY WORK. 23
upon a cross-cut tunnel or shaft at once, they will have the
most conservative form of attack if the vein proves good to
this level. But considerable development work might have
been done from the incline, on the interest upon the invest-
ment, while trying to reach the vein. No good exploitation
can be effected until the conditions of the vein are developed.
For attacking beds which are less freaky this preliminar)' in-
cline may not be justified, but with the vagarious veins this
plan seems indispensable. A subsidiary slope-entry, partially
prospects the vein ; and so long as two outlets are advanta-
geous it seems rational to first disclose its value before ventur-
ing on the tunnel, or the sump shaft and its succession of cross-
cuts to the deposit.
There is a diversity of practice as to the dimensions of a
tunnel, drift, or adit, varying with the demands upon it. The
dimensions of the main level should always be as great as con-
venient, because of its service. It may be driven in the countr}'
rock, as more advisable and safer for a permanent way, and it
not unfrequently happens that the country is softer than the
lode. For a single stope-lift one compartment suffices for
an adit. A tunnel is generally double-tracked, and frequentl)'
has an additional compartment for ventilation. The plan of
laying two or even three rails in a narrow tunnel, which is
only widened at turnouts for four rails, is of doubtful econom)'.
The inconvenience of a crowded gangwa}' is undeniable ; the
relatively low initial cost is its sole recommendator\' feature.
Yet the difference in cost is not so great as might at first be
imagined. In a large tunnel greater advantage can be taken
of the face in drilling, and but little more powder is required
per lineal foot ; the difference in cost of timbering is little, if
indeed it is anything, and the cost per cubic yard, broken, is
much less than in small headings. Not even an appro.ximate
estimate can be given of the progress and cost of driving tun-
nels. They vary from $3 to $1 5 per cu. yd. of material removed.
In granite it cost 90 c. per cu. yd., using 40 per cent Giant
and percussion drills : progress, 750 cu. ft. per da}'. In por-
phyry 200 cu. ft. can be removed, costing $1.90 per cu. yd.
24 MANUAL OF MINING.
The upper bench is driven first, after which the bottom is
easily lifted. See Chap. 8, Part II.
Slopes and shafts are of such dimensions as the hoisting,
pumping, and ventilating appliances require. Slopes of two
compartments are generally 12 to 16 feet wide, increasing to 18
or 20 feet if three are provided for. The height is fixed by the
dip and the conveyance employed. Nine feet is not uncom-
mon in a 35° dip, where the car is elevated by carriage. In
driving, the lower bench is kept in advance of the rest.
6. The preparatory workings arc far from complete when
the ore-body has been struck. Permanent gangways for haul-
age must be run and securely supported. In coal-mines two
parallel ways are driven with a rib 20 feet between them, one
from each entry. In thick and steep veins the haulage-way is
built near the floor, to facilitate loading of the cars. The airway
is smaller, and above. For the lower lifts of the mine only one
airway need be driven — the intake — if the main level of the
exhausted lift, or lifts, be connected and employed as a return-
airway. When the vein is reached, or penetrated some dis-
tance, it is then divided into blocks, according to the system
of exploitation. Gangways pitching slightly towards the out-
let are drifted right and left in the ore-body — from 60 to 100
feet apart vertically, in veins, and from 200 to 600 feet "on
the rise," in beds. They divide the deposit into "lifts," or
^'stopes." Adits serve as gangways, as well as entries.
As many of these levels or drifts are run as the necessity
for reserves, or the exploitation, may demand or the means of
the operators will permit. It is undoubtedly advisable to open
numerous and large spaces for attack, thus ensuring steady
output without " picking its (the mine's) eyes out." The)-
are extended to a natural boundary. Though the relation
between the cost of maintenance and haulage, and that of
sinking a new entry, may prescribe the limits. For exam-
ple, a thin, deep bed in good ore, having a strong roof, is
worked 2 miles from the downcast. Ordinarily, 3000 feet is
far enough. In mines working on ore as uniform as coal, or
those in bodies of known extent, only a sufficient number of lifts
PREPARATORY AND EXPLORATORY WORK. 25
need be maintained to control the output. If the ore or ad-
joining rock is soft or decrepitates, the supports deteriorate
rapidly, and induce a continual fear of danger from caves or
the evolution of gas, so but few lifts are kept open, and each
is worked out as rapidly as may be. The height of the stopes,
or the length of the lifts, and the ratio to the thickness of the
deposit, depend more upon the ore value than on the method
of mining. The distance between the levels is increased with
the hardness of the rock, the smallness of the deposit, and the
low grade of the ore. The lifts are shorter as the intended
output is large and the inclination of the vein great.
How and where to place the level in the lode is of great
importance. In the middle or on either side ? With a lode
of uniformly low-grade mineral it makes no difference. Gen-
erally it is safer to keep it in the foot-wall, or along it, if the
country is softer. Injury by subsidence is less, and seepage of
water is more readily taken care of. In thin veins the foot-
wall is cut away to secure height for the car, and in thin beds
the roof or floor, whichever is the softer. In thick beds the
gangway is in the lower bench. If the mineral is in a small
streak, it is followed as it jumps from wall to wall, unless the
divergences from a straight line are too great. Otherwise the
" level " is continued straight, without regard to minor devia-
tions or rolls, on a grade of I in 200. The dimensions depend
much upon the nature of the ground and the length of time it
is to be maintained.
This class of work is very expensive, compared with ore-
extraction, and for this reason is called "dead work." But it
is indispensable, as exploratory. Though primarily' unproduc-
tive, its location bears vital relation to the mine econom}-. Be-
sides careful timbering, heavy stump and chain pillars of ore
are left for support, the mineral of which is only incompletely
recovered when the lift is abandoned. Indeed, all permanent
ways should be so protected as not to jeopardize lives or the
mine. Shafts should be surrounded by from 30 to 60 feet
of unworked vein ; haulage-ways in beds, by pillars 60 feet
wide on either side ; stopes, by arches of lo or 20 feet thick.
26 MANUAL OF MINING.
A fair ratio of total dead work to stoping-ground opened is r
to 8. In beds the unworked matter for support nearly equals
the amount designed to be mined in the rooms.
All rocks are more or less uniformly creviced. Stratified
rocks, for example, have horizontal planes of growth and verti-
cal planes called joints, caused by shrinkage. Some coal-beds,
besides the horizontal planes of cleavage, are cut by one set of
parallel planes only, others by two sets, producing rhombohe-
dral coal. These cleavage planes are called "cleats."
As crevices facilitate the breaking of rock, so do these
" cleats " the mining of coal. In fact, in soft coals of small pitch
the direction of the cleat alone may determine the direction
of the gangways. In order that the working faces may be
against the cleat, the most important drifts are with the cleat.
This is not so true in anthracite veins because strong ex-
plosives are used. In steep-pitching coal-seams cleat is of less
importance than the grade of the haulage-ways. Here the
main galleries are with the strike, or slightly diagonal to the
rise, the butt headings (see Fig. lo) being nearly perpendicular.
They should not be driven far before breaking off the face-
entries.
Deviations in the course, or changes of rock, occur in the
lode, often so imperceptible as to lead the miners away from
the vein. The freaks, horses, " jumping" of the streak, pinches,
or faults may have gone unnoticed. A temptation to follow
the softer country rock often accounts for "losing the vein."
It is of common occurrence. In such event, fresh exposures of
the sides of the level should be carefully examined for some
distance back, to ascertain the point of departure and its cause.
Cross-cuts in the lode may even be necessary.
If a faulting dike or cross-course is encountered, its strike
and pitch are noted. After cutting through to the other side,
the character of the rock is examined. In stratified country
the rock encountered should be identified, and its geological
position, relative to the ore-bearing stratum, known, thus guid-
ing the engineer. But if the opferations are in massive rock,
the problem assumes a serious aspect when he attempts to fol-
PREPARATORY AND EXPLORATORY WORK. 2"]
Jow the prolongation of the vein beyond the plane of the frac-
ture. It is a matter of record that fully 8o per cent of the in-
tersected veins were heaved, apparently, to the right or left.
Those to the right are twice as many as those to the left. Hen-
wood also discovered that the heaving to the side of the greater
angle is five times as common as to the smaller angle. In
every district may be found a rule for finding the other end of
the vein. But it is purely of local application and unreliable. To
formulate a general rule out of these numerous and apparently
eccentric displacements would seem well-nigh impossible ;
but Herr Schmidt, in 1810, offered a solution to the problem,
which, though not infallible, is the best extant and has done
valuable service. " When the cross-course dips away, after
going through it, the drift is run along its far wall in a direction
opposite to that in which the vein pitches. If it dips toward the
mouth, the drift is carried along the far wall, to the right or
the left, as the vein dips to right or left." The amount of the
displacement, i.e. the distance to be drifted for the continua-
tion of the vein, cannot be premised. It varies between very
wide limits, and is thousands of feet in many localities. Hen-
wood averages the throw of veins at 16 feet.
The vein is still further divided into parallelopipeds, by
mill-holes 50 to 1 50 feet apart. Through these the mineral
descends to the level, from which they are upraised. Winzes,
or secondary shafts, do similar service, but until connection
with the lower level is made the mineral is hoisted from the
stopes they work.
7. Quarrying is the simplest means of extraction. It dis-
engages large masses, and admits of operations on a large face.
It may be employed for all deposits near the surface, when the
removal of the alluvial and friable rock is cheaper than timber-
ing them up. Slate, building-stone, iron, lead and zinc ores,
peat, coal, graphite, and mica are thus mined. The overlying
loose material is stripped, and pays better than mining, so
long as not over 4 yards of soil must be removed for each yard
of coal. Practically all the deposit is recovered, and to a mod-
erate depth is quite profitable. The point selected for the
28 MANUAL OF MINING.
beginning of the work, and the discharge of the output, is the
lowest convenient spot for transportation. Hoisting is accom-
phshed by derrick and buckets ; drainage, by bore-holes and
wells sunk deep enough to drain the pit. The influx and ac-
cumulation of surface-waters give trouble, which is somewhat
relieved by ditches and drains dug alongside the quarry. But
the limit is soon reached with the difficulty of propping the
unsupported sides of the cave. In the Tilly Foster mine this
problem is solved by the blasting away of 200,000 tons of the
hanging wall. Such work is dangerous and uneconomical,
though it is systematically employed for iron ores all over the
world. Nevertheless, the critical moment must come when a
more rational method will be necessary. It is difficult, however,
to induce a change to the more expensive underground work,
and where it must ultimately be adopted the previous quarry is
deprecated. Increased pumping-machinery and more timber,
ing will be required than if the mine had not been previously
injured. Several properties might be mentioned, in Leadville
and Lake Superior, in which vast quantities of ore were lost in
the caves primaril}' caused by originally working as an open
pit. Nevertheless, quarrying by the steam shovel is common.
The above strictures placed upon quarrying do not, of
course, apply to the extraction of structural materials, which
always occur superficially and flat over extensive areas. Build-
ing and mill stones are best recovered by open work, and easily
mined in blocks by trenches and channellers (see Chap. VIII,
Part II).
The getting of salt is generally by a special process. It is
always found in old river-beds, and quite liberally distributed
over the world. In England and in Germany the thick beds
are mined systematically. Elsewhere, the heavy investment
of capital involved would militate against the mining of impure
beds, especially if cheap fuel is to be had. Then holes are
drilled to the bed, water poured down, and the rock-salt
leached out. A pump-pipe is carried to the floor, and the
strongest brine thus drawn. It will be seen that the capital
required is thus reduced to a minimum, and the output may
PREPARATORY AND EXPLORATORY WORR-. 29
be increased at a moment's notice. There will be no expense
for storage, and no deterioration. This solvent process is also
used in mines which have collapsed. The brine is evaporated
by solar heat, or boiled in drying-pans. One ton of coal will
evaporate 1600 gallons of brine, carrying -jy bushels of salt.
Hydraulic mining is a species of open work, in which
water is the agent for removal. The main objection to it is the
damage done by the sediment and waste in inhabited regions.
An ore of 20 cents in gold per cubic yard pays. A. Bowie's
" Hydraulic Mining " is a complete work on the subject.
The exploitation of peat and phosphate beds is by dredg-
ing. In heavy bogs of the former, canals are run for drainage,
and for the navigation of a scow, which cuts away the peat.
Afterwards it is pulped, pressed into blocks, and dried. This
furnishes a clean, cheap fuel. Phosphate rock, for fertilizers,
is dredged and grappled for, in rivers and deep water, by ma-
chines. Peat, or fertilizer above water-level, is quarried in
steps.
Materials which occur in large bodies, and regular, require
systematic exploitation. Short fissures, feeders, gash-veins,
and pockets can hardly be classed as other than special depos-
its, for which local conditions determine the means of mining.
Beds and vems of clay, salt, coal, gypsum, and the metals have
a continuity and a consistence sufficiently uniform to admit
of classification as minable masses. They are found in all
manner of positions, with varying boundaries and variable
admixtures of foreign substances. There is always a right and
a wrong way of doing things, so it rests with the operator to
select the best method of husbanding the resources of his
mine.
The cost per ton is by no means the sole consideration. A
speedy and complete removal is of utmost importance. Dif-
ferences in dip and thickness, the relative amount of barren
rock in the seam, the amount of gas, and the character of the
bounding walls, are the factors determining the choice. Other
elements of perplexity are added to the problem, as the friabil-
ity of the ore, the dismtegration of the vein matter, and its
30 MANUAL OF MINING.
value, but these are of minor import. It should be borne in
mind, also, that each method has its special adaptability.
Numerous instances of failures may be quoted resulting from
the error in the adaptation of a good method to wrong condi-
tions, and it is earnestly hoped that a careful perusal of the
following brief conditions may be of assistance to mine opera-
tors.
Whatever the method, first, facilitate the breaking of min-
eral by making the working places large, with ample, free, face ;
second, concentrate the workmen as much as possible ; third,
reduce the length and cost of gangways to a minimum, keeping
them open, only so long as needed, for sloping and the robbing
of the supports.
The steam shovel with its dredger and derrick plays so
important a part in the operations of extracting the soft iron
ore of Wisconsin and Minnesota as to be worthy of mention
among the economic methods of ore-mining. Tliat it has
revolutionized the iron-manufacturing industry there is no
doubt; for more than 13,000,000 tons of iron have been
e.xtracted for the past four years by its aid.
Below are cited some references:
Trans. M. &^ M. Enj^.: Methods of Salt Mining in Austria, C. Schraml
and A. Aigner, XLIV. 89.
Coll. Eng.: Leith Coal Mine, H. L. Auchmuty, Aug. i8g6, 3; Placer
Mining, Prof. Arthur Lakes. May 1896, 219 , Faults, F. T. Freeland, Nov.
1892, 80.
Mineral I ndust7-y : Quarrying Flagstone, David P. Jones, III. 495;
Mining Cryolite, Charles Hart, II, 302.
Coll. Guard.: Deep Mining, William Thomas, June 1897, 1104; Dec.
18, '96, p. 1170.
.State Alin. Bureau : Mining Gold Ores in California, loth Rep. 852.
Journal Geology ■ Development of Cleavage, IV. 444,
iV. Stajf. hist.: On Cleavage Planes, and their Influence on the Eco_
noniical Working of Coal, G. G. Andre, II. 132.
Anier. Inst. M. E.: Hydraulic Mining in California, A. J. Bowie, Jr.,
A. B., VI. 27 ; Folds and Faults in Anthracite Beds, B. S. Lyman, XXV.
327.
School of Mines Quarterly : Drift Mining, T. Egleston, VIII., No. 3,
204.
E. Gr' M. Jour.: Vertical Shafts and Cross Cuts vs. Inclines on the
Vein, LVI. 662.
CHAPTER III.
METHODS OF MINING.
8. Analysis, discussion of the general applicability of mining, "re
treating," differences between coal and metal mining; the least
niiiiable thickness of deposits. 9. Overfiand and underhand methods,
comparison and applicability of ; account of the long-wall system;
details of the plan ; gob roads and their care. 10. Pillar and stall
method of mining; dimensions of rooms and of pillars; creep, cave,
crush, or squeeze, and their prevention ; orderand manner of winning
pillars; mining loss and waste. 11. Modifications of the pillar and
stall system ; the " County of Durham ;" the " Wasmuth ;'' barrier
pillars; relative merits of long-wall and pillar and stall; panel sys-
tem ; " square work ;" gallery and pillar." 12. The American sys-
tem of " square sett," as applied to veins and beds ; modes of mining
thick seams, in slices or by filling or caving; traverses with filling or
with caving.
8. Deposits containing organic, earthy, or metallic min-
erals may be flat or steep, thicl< or thin, and accordingly the
systems for their extractions ;irc :
Dip less than 45'.
Dip exceeding
45^
( I,n.\(;-WALI friable or soft roof.
Under 6 ft. thick. - Pillar and Stall. / <-
I Flat Stopls. \ ^™ °''^-
Panei gaseous coals.
f Gallery and PiiLAR..hard ore.
Method OF Cavi.ng. j . ,,.
^ r f. .u- I I ■< .' 17 . . .- ( yield ine; v — the weight of one turn of
rope on the small end)r must balance (B -\- the weight of one
turn of rope on the large &\\6)d, and still equal the constant
Bd = j\I. So, for each revolution throughout the journey,
this balance should be equal to ]\I. This is satisfied by the
formula
V z:: 2;r« =
= d
V?
2r' 2d''
Rr
+ ^s.n -^-^s,n ■^,^.
The last two terms may be neglected without sensible error.
In the above equation, i' is the total arc of revolution
■described by the point on the rope at the small end between
the beginning and the end of the hoist.
The curve of the drum is then constructed by substituting
■different values for r and d, which are the limits of p, placing
the second member equal to 27111, and solving for 71, the
number of grooves. The various assumed values for p are
radii of the curve at the various points along the axis which
are at a distance from the initial point equal to horizontal
pitch, P, multiplied by ;/. The curve so plotted is the section
of the drum which will fulfil the conditions, furnishing an
equalization throughout the journey, so long as the length
and weight of the full rope remain the same.
In an example cited by the author, D = 2000 feet, 7? = 3
pounds, B = 4000 pounds, r = 4 feet; then AI = 40,000
foot-pounds, and d becomes 10 feet. Solving the equation
9° MANUAL OF MINING.
and equating with 2Ttn, we have for (/ = lo, « = 4, « = 55.8.
That is, between the initial and final points, there are 55.8
revolutions of the drum. For r = 4 and d = 9, n = 53-3
revolutions; in like manner for (^= 5, n^ 35-1 I ior d =^ 7,
n = 44.4; and for d = 8, n ^ 49- S-
Another form of counterpoise is a tail-rope extending
from underneath one cage, under a sheave at the bottom of
the shaft and up to the floor of the other cage. The dead
weight on each rope is constant; the oscillation of the cage
is reduced, a regular speed quickly attained ; friction, also the
size of the rope, is increased. A shaft free from impediments
is necessary, as also a dry pit. Another plan employs a
heavy weight, and a chain wound on an auxiliar}' drum in
such a manner as to alwaj^s balance the ropes in any position
of the cages. On the drum-shaft a third drum is attached.
This drum winds and unwinds a wire-rope, which with a chain
at the end hangs down an auxiliary shaft, or down the ladder-
way of the hoisting-shaft. The length of rope is such that
when the two cages in the hoistways are passing opposite each
other the entire chain is coiled up in a box provided at the
proper point. The weight of the chain must be sufificient to
balance the weight of the full length of hoisting-rope, and at
all points in the hoist the amount of suspended chain must
balance the difference between the weights of the two pendent
hoist-ropes. As the loaded cage rises from the bottom the third
drum commences to lower the chain into the box, and lessens
the weight hanging from it to assist the engine in balancing the
heavy rope being hoisted. When the cages pass each other
the two ropes balance, and the chain is not operating, the
counterbalancing rope being all paid out. See Fig. 240.
As the loaded cage continues to rise the drum commence
to wind the counterbalancing rope in the opposite direction,
thus raising the chain and bringing its weight into play as a
counterpoise to the weight of the descending rope.
Ifi a shaft of 2200 feet deep, the counterbalance-rope is
700 feet long and its chain, 580 feet, weighs 4320 pounds.
The size of the chain is graduated to meet the varying weights
HOISTING MACHINERY.
91'
to be lifted. Thus 104 feet are of f-inch chain, 162 feet of
I, and 314 feet of |. The counterbalance may be so adjusted
as to enable it to hoist from any level. Its sav-
ing in fuel is very great. It is simple and
cheap, and works smoothly.
The Koepe system of winding meets almost
all the requirements of a perfect equalization,
and is highly efficient. It ensures against over-
winding, decreases wear, and dispenses with the
enormously heavy drum, using a sheave instead.
The two cages are connected by tail-rope below
and by main rope above. Then the engine does
a steady, uniform work of lifting the net load
only. Hoisting is possi-
ble only when the friction
caused by the loads on
both ends of the main
rope is greater than the
weight of the net load
carried on the rising cage ;
and in several localities it
has been abandoned, be-
cause, immediately after
oiling, the rope would
slip and the work was Fig. 30. Fig. 31.
unsatisfactory. By counterbalancing, the work is only that
of raising the live load -\- friction. Single hoists (unbalanced)
are excessively wasteful in power and fuel, and hard on the
brakes. The fuel value of hoisting 1000 feet of rope and a
heavy cage thirty times an hour is no small quantity.
It may be well here to mention a most useful piece of
apparatus, and by no means superfluous about a mine, for
handling heavy articles — a portable tripod and a Weston
differential-pulley block. It is simple enough to be manip-
ulated by any one without fear of injury by rough treatment,
and is exceedingly powerful (Fig. 31).
The following may serve as references for those desiring
to further investigate the subject-matter of this chapter.
92 MANUAL OF MINING.
Amer. Inst. M. E.: The Relative Value of Coals to the Consumer,
Dr. H. M. Chance, XIV. 19; Fuel-economy in Engines and Boilers, P.
Barnes, XIII. 715; The Equalization of Load on Windmg Engines by
the Employment of Spiral Drums, E. M. Rogers, XVII. 305; Note on
the Koepe System of Winding from Shafts, John M. Harden, XVII.
429; Pneumatic Hoisting, H. A, Wlieeler, XIX. 107, Hoisting-engine
Indicators, R. A. Parker, XVI. 39.
Etig. and Mill. Jour.: Reel and Hoist at Boston and Montana Mine,
B. V. Nordberg, Mar. 1S97, 285.
Men. Industry : Value of Coal, T. L. Wilkinson, July 1896, 632:
Largest Hoisting Engines in the World, Anaconda, W. McDermott, Dec.
1896, 268; Boiler Economics, T. L. Wilkinson, June 1896,612.
Scientific Quart.: A New Era in Mining Machinery, Prof. M. C.
Ihlseng, Mar. 1893, 65,
Trans. N. of Eng. M. &^ M. Inst.: Compound Winding Engines in
Idria, C. Habermann, XLVI., part 3, 55; Equalizing Load on Hoistcr
by Balanced Chain, A. Despres, XLVI., part 3, 56; Compound Winding
Engine at Cardiff, W. Galloway, XLV. 205.
Lake Sup. Min. Inst.: A Single Engine Plant, IV., 1896, 8r.
///. Min. Inst.: Hoisting Engine, Direct Acting, i, 145.
Coll. Eng.: Methods of Equalizing Load on Hoister in Butte, Mon-
tana, C. S. Herzig, Aug. 1896, 25 ; Comparison of Boilers, serial article,
Wm. Kent, June 1897, 499; Heat Calculations, Combustion, W.Kent,
Feb. 1897, 370; Nature of Defects in Management of Boilers, May 1S97,
439; Electric Hoists Discussed, May 1897; Progress in Mining Machi-
nery, G. E. J. McMurtrie, June 1897, 505 ; Mining Machinery, Butte,
Montana, C. S. Herzig, Aug. 1896, 25 ; Steam-engine Work, easy lessons,
Dec. 1896, 225; Lecture on Foundations, W. H, Mungall, April 1896,
207.
Mineral Industry: Mining Machinery, Butte, Montana, R. G.
Brown, III. 177.
Amer. Mnf.: Boiler Erection, Adjustment, July 1897, 115; Superior-
ity of Water Tubular Boilers, Geo. Shaw, Jan. 1897, 113.
Coll. Guard.: Economic Tests of Boilers, H. B. Dickmann, Dec. 1894,
1 134; The Calculation of the Calorific Power of Coal by Du Long's
Law, M. G. Arth, Oct. 1895,683; New Winding Arrangement for Mines,
A. Despres, LXXII. 163; Economic Working of Engines and Boilers,
Bryan Donkin, June 1897, 11 89; Management of Boilers, Efficiency, etc.,
E. |. Duff, Jan. 1897, 206; Steam-engines in Coal Mines in England, R.
L. Galloway, Dec. 1896, 1060; Hoisting from Deep Shafts, Walter Mc-
Dermott, Sept. 1896, 553; Hoisting from Deep Shafts, B. H. Brough.
Dec. 1896, 1 170; Air Shaft for Winding, adaptation, M, P. Vanhassel,
Nov. 1896, ion; Law as to Removal of Fixtures and Machinery, edi-
torial Sept. 7, 1894, 442; Steam-engine Breakdowns, Shaft-cylinder
Valv«s, M. Longridge, Nov. 1896, 965.
HOISTING MACHINERY 93
Coll. Manager : Boiler Economics, lecture, W. H. Fitton, Jan. 1894,
3; Mining Machinery, lecture, John Hunter, 1894, 4; Distribution of
Power in Collieries, L. B. Atkinson, Jan. 1896, 20.
Engineering Mag.: Boiler Economics, A. A. Cary, Mar. 1897, 959;
Economy of Engine Selection, C. H. Davis, Oct. 1896, 15.
Trans. Am. Soc. C. E.: Hoisting, comparative article, G. A. Good-
win, XXIX. 695.
Queensland : Testing Boilers in Remote Localities, report 1895, 35.
Idaho Agric. E.xp. Sta.: Boiler Corrosion, Water Analysis, Table,
Chas. W. McCurdy, July 1894.
Root's Catalogue : Relative Factors of Evaporation Table.
Heine "Helios" : Relative hp. Conversions.
B. cS" ll\ "Steam": Properties of Saturated Steam, Babcock &
Wilcox Co. 20th ed. 71.
S. of M. Quart.: Equalizing Load on Hoister, description of Methods,
Chain, etc., H. W. Hughes, X, 1889, 260.
Chest. Inst.: The Koepe Patent System of Winding at Bestwood
Collieries, Robert Wilson, XL 267; Coal Winding in Deep Shafts, A. H.
Stokes, VL 248.
Eng. Soc. of Jl'. Pe/ina.: Losses in Boiler Practice and Some of tlieir
Causes, Daniel Ashworth, X.; Losses in the Steam-engine, William A.
Bole, X. 2; Foundations, W. G. Wilkins, IX.; An Luproperly Designed
Cliimney, Gustave Kaufman, IX.
C/. S. Geological Survey : Feats of Labor, IV. 322.
E. &^ M. Jour.: Mechanics of Hoisting Machinery, Dr. J. Weisbacli,
LVI. 565; Petroleum for Boiler Incrustations, LVI. 525.
• CHAPTER V.
ELECTRICITY AND WATER-POWER.
1 8. Application of electricity and water-power to long-distance trans-
mission; comparison with mechanical means; universality, to all
operations of mining. 19. Conducting wires, size, etc, ; two-wire
and three-wire systems; safe voltage; explanation of tlie electric
units, and formulae; conversion of electric into kinetic energy by
motors; efficiency of motors ; storage batteries. 20. jMode of obtain-
ing water-power by the use of Lef^el, Knight, and Pekon wheels;
description, efficiency, and application of the plants and machines.
(8. The most valuable acquisition made to an}- branch of
industry during the past few years was electricity, and with
phenomenal rapidity it has gained favor. Not more than six-
teen years ago electricity was a mystical force that was not
suspected as capable of operating even a telephone. To-day
the installation of a plant ceases to be a novelty ; and its utility
as an illuminator, and a power capable of long-distance trans-
mission, is unquestioned. It is true, it lias not yet realized all
the hopes and anticipations of its zealous advocates. Serious
objections have been raised against it, and many plants have
proven failures, yet it has so demonstrated its merits that, with
better understanding, it cannot fail to work an entire revolu-
tion in the industries.
Electricity may be carried to any moderate distance, in an)'
desired quantity, through a small light conduit on inexpensi\'e
supports and with slight loss. It offers great assistance to en-
gineers in utilizing remote cheap sources of power, and is des-
tined to supersede all known methods of power transmission.
It is preferable /cr se, and because the difficulties in the actual
transference of matter by mechanical means over the inter-
vening distance are great. The difficulties increase with the
94
ELECTRICITY AND WATER-POWER. 95
distance in any of the systems, but those with electric are less
than with mechanical methods, appliances whose great initial
cost and low efficiency have hitherto restricted our work. The
first cost of a moderate-sized plant is considerable, compared
with other modes; but, once installed, it is easily capable of great
extension. Its efficiency is high : whereas a fine steam-engine
pays out to the recipient belt only 14 per cent of the fuel
energy consumed in the boiler, a dynamo will convert fully
90 per cent of the total water-power into electric energy. The
former will consume, perhaps, 2.5 lbs. of fuel per hourly horse-
power, which is saved to the latter. The first cost may, in cer-
tain cases, favor the latter.
The losses from condensation, friction, etc., in the conduc-
tion of steam cannot but be great. If the engine operates an
air-compressor, the efficiency is reduced from 14 to 10 per cent
at least. As a matter of fact, neither steam nor compressed
air can be converted into power with a loss of less than 50 per
cent of the energy received. Hence from S to 7 per cent is
the best that can be expected from the use of these expansive
fluids, which can never be regarded as serious competitors,
except within a very limited scope. Then, compare the cost
and inconvenience of large thick pipes required for the conduc-
tion of air or steam with the ease and rapidity of laying, sup-
porting, and insulating a mile of wire. Wire rope gives better
results; but for distances greater than half a mile it is super-
seded by electricity, because of the losses by friction ; besides, it
can transport power to a certain class of appliances only.
On the other hand, electricity subserves practically all the
operations of mining : signalling by annunciators or indicators,
lighting, blasting, drilh'ng, hoisting, haulage, etc. It neither
vitiates the air, as do engines ; nor fog and chill it, as compressed
air. There is no leakage of power when the motor is not in
use, as with other means, and is especially commended when
the power is to be intermittently required. A copper wire \ of
an inch in diameter is equivalent to a 3:^-inch air-pipe, or ^^
wire rope, for conveying power at average pressures ; cost,
I : 27 : 19 for equal lengths.
9^ MANUAL OF MINING.
19. The electrical units are, Ampere, Volt, and Olim,
respectively, measuring the quantity C, pressure E, and the
resistance R, of a current. Ampere is the unit of current
strength, measured by the deposition of metal from a solution.
(0.017253 grain of silver per second, or 0.005084 grain of
copper). The unit of resistance is the OIivi, which equals the
resistance of a column of mercury i square millimeter section
and 1060 millimeters long. A Volt is the unit of electromotive
force (usually written E. M. F.) and expresses the difference
of potential, or of electric pressure. Its value is arbitrary,
but fixed. One volt will force one ampere through one ohm
of resistance. The energy, P, of a current is measured by
the product, CE, in Watts (the unit), 746 of which equal a
horse-power. The number of horse-power in a conductor
equals CE divided by 746.
P = CE, E - CR.
A Joule, = IF, Is the work done or the heat generated by i Watt in a second.
J-F = (?£ = 0.7373 ft. -lbs.
Manufacturers' tables furnish the data for wires of various
sizes, by which their resistances may be known. For exam-
ple, 1000 feet of No. i gauge copper wire (0.37 inch in
diameter) offer a resistance of o. 1 147 ohms and consume 18
volts with a given current of jy.J amperes.
The electric fluid is conducted by copper wire, the size of
which is commensurate with the quantity of energy to be
transmitted. The transmission is realized, irrespective of dis-
tance, with only a slight loss due to the heating of the conduc-
tor and poor insulation. This represents a loss of power
which varies with the length and area of the wire. The loss
of electric pressure, E, in volts, is equal to the product of
the quantity, C, in amperes, of electric fluid to be carried, and
the resistance, R, in ohms, of the conduit of given length and
diameter. The value of this loss of energy, in Watts, is
expressed by / = CE. Usually, however, a drop in voltage
and the heating limit of the wire are of more consequence
than the mere waste of a small fraction of total energy.
The drop in voltage increases inversely as the area or the
square of the diameter of the wire, and this is reduced to a
ELECTRICITY AND WA TER-POIVER. 97
minimum by the use of a large wire, which, however, increases
the largest item in the cost of insulation. On the other hand,
the employment of a high voltage is possible, the generation
of which is only slightly more expensive than that of lower
pressure, and such a high voltage can be safely carried by a
small conductor when special care is given to its insulation.
The economy of electric transmission, as is true also of
pneumatic or hydraulic transmission, increases with the
pressure employed; for outdoor work, only the difficulties of
insulation of a high voltage limit that which may be trans-
mitted on surface lines; for mining work, the question of
safety determines the limit of voltage at a maximum of 450,
though the fire dangers of a higher tension current may be
eliminated without prohibiting the use of a bare wire of ample
size. While the allowable expenditure for wire in any given
plant will determine the electromotive force which may be
used and the efficiency of the plant required will fix the line
loss to be allowed, the most economical area of conductor is
that for which the annual interest on capital outlay equals the
annual cost of energy wasted. In determining the size of
wire required for mine work, the allowance for the drop in
voltage is about 15 per cent, or even 20 per cent, of that of
the current at the generator. The expression in electric units
for the required diameter of a conducting wire is
d'' = ii.AfiDC ~ -i-r,
wherein D is the total length of the wire in feet, V, the
initial voltage of the current, and x the decimal percentage
of loss allowed.
The gain in the use of high-tension electricity is well
illustrated by the above equation; but owing to the difficulty,
if not impossibility, of preventing leakage at the commutator
of a continuous-current generator, the limiting difference of
pressure permissible at the terminals of its wires is looo volts.
Witli the use of the alternating-current machines, however,
there is no limit to the electromotive force which may be
given to the current. So that when electric power is to be
generated at a great distance from the point of its application.
98 MANUAL OF MINING.
a high-potential alternating current may be generated and
transmitted to the point of distribution at the mine, where a
transformer may reduce the high-pressure current to one of a
pressure low enough to be safely employed, and, in addition,
may convert the alternating to the more convenient contin-
uous current. The employment of transformers has rendered
it possible for numerous small mines to install electric plants
which formerly were prohibited because of the excessive
amount of wire required. At present the cost of erection is
far greater than the cost of the wire.
When the current from a locomotive motor is returned by
the steel rail to the generator, the rail-lengths are well bonded
and their cross-sectional area is at least seven times that of
the copper wire which would otherwise be employed, or of the
trolley wire.
The alternating-current system, or rather a modification
of it known as the three-phase system, offers particular advan-
tages for the transmission of power, and if three wires are used
for the current, all varieties of the mine machinery may be
driven with the same loss in transmission using the same initial
voltage as in the two-wire continuous-current system. In case
the continuous current is desired for the locomotives in lieu of
the alternating current, a rotary converter can be placed on
the line to transform the one into the other, and even also to
reduce the voltage to the pitch necessary for the new use.
The conversion of electric into kinetic energy is accom-
plished by a motor directly connected with fixed or movable
appliances (Fig. 32), which may be operated by rotary motion;
for the reciprocating motion of pumps and percussion drills, it
has signall}? failed. Rotary drills, fans, bolsters, and coal-
cutters are in successful operation, with an efficiency of from
60 to 80 per cent of the energy received. Neither the genera-
tor nor the motor is a large or a complicated piece of machin-
ery, being easily transported and run. It therefore admits of
introduction within the prescribed limits of the stope or gallerj'.
No power is consumed, and none transmitted to machines which
are idle, and the power is always proportional to the work
doing. The commercial efficiency of the motor is nearly the
ELECTRICITY AND W ATEK-POWEK.
99
same, whether working at full capacity or not, and it quickly
responds to recurrent demands upon it without excessive loss.
If the three-wire system is used, then all motors not requiring
frequent handling should be connected to outside wires ; drills,
and the like, to the neutral wire. This plan lessens the press-
ure on the motors. For lighting, continuous or alternating
currents may be used with equal efficiency ; but for motors, I
do not believe the alternating current can be advantageously
used. When one recalls that the current which furnishes the
power likewise gives brilliant illumination at the work, one
must confess the superiority of the entire discovery.
When the evolution of the storage battery has reached an
efficient stage, an important adjunct to mine appliances will
have been attained. As yet the storage battery is tentative.
For a proper knowledge of this subject, which is of too ex-
tensive a scope for introduction here, the reader is referred to
J. P. Jackson's " Electromagnets and the Construction of
Dynamos," Kapp's " Electrical Transmission of Power," and
Dr. Louis Bell's " Electric Transmission."
20. Water-power has long been employed for operations
in the immediate vicinity of the wheel. No cheap and effi-
cient means had been discovered for its transmission to ijreat
'OO MANUAL OF MIiVIXG.
distances above the wheel, until the successful enchainment of
electricity to man's use. The installation of electricity has
opened up the possibilities of water-power to a marvellous
degree, with but one disadvantage — the limitations of seasons
in drought or cold. The gross power of water is the product
of the weight discharged, by the height [h) of its fall. W=^
62.5(7. The net power is from 40 to 90 per cent of this,
according to the kind of wheel used, whether breast, overshot,
turbine, or hurdy-gurdy. Q = cubic feet, delivered per minute.
Then horse-power = o.ooi6\Qh.
In the early days of the undershot and overshot wheels,
enormous volumes of water were consumed by large slowly
turning wheels, in developing small power. The Leffel and
other forms of turbines were next in order. These are quite
small, and, revolving at high speed, give a good duty with
large volumes of water, under moderate heads up to 300 ft.
They may be placed with an axis horizontal or vertical, the
largest size being 48", submerged at the bottom of a penstock,
or encased in a globe, or cylindrical casing, connected to the
bulkhead or piping, by which the water enters centrally and
discharges circumferentially. The globe casing with a horizon-
tal axis is the preferable form for mining purposes.
In our mountainous districts the numerous creeks are not
large ; but their fall, and hence their velocity, is great, and it is
rare that water-power can not be found within a moderate dis-
tance of the mines. This, the "hurdy-gurdy" wheel has been
designed to utilize ; and most effectually is it done, giving, as
it does, a guaranteed duty of 85 per cent (Fig. 33).
A wheel 18" to 90" diameter, the plane of which may be in
any convenient position, carrying a number of small cup-shaped
vanes, receives the impingement of one or more jets of water at
high velocity, and tangentially. This principle is entirely at
variance with the previous methods of generating power, and
most nearly conforms to hydraulic laws. Its execution is sim-
ple, and a pronounced success, the entire absence of machinery
leaves nothing to get out of repair. Placed at the lowest prac-
ticable point, to obtain all the head available, the high velocity
-of even a small volume of water delivered through the nozzles,
ELECTRICITY AND WATER-POWER.
lOI
will develop an enormoi's power. Though essentially a high-
pressure machine, it is almost as efficient with a moderate
head. Thirty feet is regarded as the inferior limit of head,
while theoietically there is no maximum limit. It is actually
in use with a head of 1,700 feet, and a measured velocity of
102 MANUAL OF MINING.
revolution of over 7000 feet per minute. The size of the
wheel may be proportioned to the rate of revolution desired
for the main shaft. A small wheel at high head has a very
rapid revolution, and would admit of a direct connection from
its pulley to the dynamo, while for slow motion of pumps,
air-compressors, etc., a large wheel is desirable.
The Pelton and Knight patterns of wheel are of this type
of impulse-motors, and while several European forms are on
the market, a hasty glance at them suggests that their parts
are not as accessible for repairs as those of the American
models, which are durable, reliable, efificient, and easily
accommodated to wide variations of power. The secret in
the extraordinary energy obtained from the use of these tan-
gential reaction-wheels lies in the fact that the entire dynamic
pressure of the water is utilized, as may be shown from the
fact that the water falls from the buckets perfectly inert, none
being carried over. The manufacturers guarantee an efficiency
from these wheels, when properly regulated b}' governors, to
be 85 per cent of the theoretic head due to the velocity of dis-
charge from the nozzle against the wheel cups. The Leffel
turbine wheel receives its power from the pressure of a head
•of water in the ditched penstock, and delivers an efficiency of
about 90 per cent, with heads not exceeding 80 feet. It is
•evident, therefore, that in regions where the fall is great and
the volume of flow small, impulse-wheels are to be preferred
to the turbine wheels, which, while giviiig equal efficiency
and as much power, require a larger volume at a small head.
The water is carried from its source to the wheels either
through a contmuous line of pipe, which should be as large as
admissible, for the first class of wheels, or by a ditch for the
second class. The pipes are dipped in tar or asphalt, laid on
the ground and strapped or chained to posts or stumps driven
for the purpose. The slip-joint connection is better than the
ring-joint (Fig. 79). The supply of water is estimated in
" miner's inches," which term, while indefinite, represents a
flow of about 1.5 cubic feet per minute. By a "miner's
ELECTRICITY AND IVATEK-POVVER. IO3
inch " is known that volume of water which is discharged
through one square inch of an aperture which is 2 inches liigh
and 4 inches long, cut through a plank 1.25 inches thick, the
lower edge of aperture being 2 inches above the bottom of the
measuring book and the upper edge 5 inches below the level
of the water.
In order to assist the engineer in determining the size
of pipe requisite for a given flow of water, the following for-
mulae are given. There is no simple relation between the
theoretical and the actual discharge of water : for the condition
of the inner surface of the pipe, its smoothness and freedom
from rivets, laps, and intruding gaskets, and the length of the
pipe, are elements affecting the resistance to the passage of
the fluid. Elbows or bends in the pipe and variations in its
diameter also have an important bearing upon the efflux. The
frictional resistances are directly proportional to the length, are
inversely as the diameter, and increase with the velocit)'. The
effect of elbows may be separate!)' determined while each
change in the diameter, whether of enlargement or contraction,
causes a reduction in the flow that may onh' be ascertained by
special investigation.
Assuming, however, very long clean pipes of a uniform size,
the resistance due to friction of the fluid in the pipe is ex-
pressed by the formula
IQ'
/'^ 0.1007/^^.
This is usually measured by a column of water, which must
afterwards be subtracted from the total head H in order to
obtain the effective height that will produce a given velocity
or discharge a given quantity. This height or loss of head is
li. In clean pipes of smooth bore /is 0.003, nearly, and in the
ordinary mine pipes it is taken at 0.0053. The theoretical
quantity discharged in cubic feet per second is 6.3^' \ H .
But the actual discharge and the loss of head arc found to
be at variance with these calculated results, and numerous em-
pirical formuljE have been prepared, a substitution in which
I04
MANUAL OF MINING.
gives a closer approximation to the measured quantities. The
{oliowing are selected (all the units being in feet or seconds).
//is the total head ; h, the loss due to friction in the pipe;
/, the length ; d, the diameter ; Q, the quantity discharged at
velocity; v — i.2'j'>,Q/d'. For a certain fixed loss of head, h
Ii — 0.000606/
(2"
d--
0.000606/
(?'■
h _
O, for the maximum horse-power,
(o.ooi;/)"-^"-
The maximum horse-power to be obtained is equal to
I
H. P. = 2.466II^-^^\j^)d^-
Example i. — A pipe is 500 feet long and 3 inches diameter. What should
be the head to produce a discliarge of iSo feet per minute ? 3124 feet.
Here, (p = 3, / = joo, ;/= 0,25, and assuming/ to be 0.00566,
// = o 1007 X o 00566 X 500 X 9 X 1024 = 2624 feet.
Ex. 2. — What diameter should it have to deliver the same quantity of water
with a head of 82 feet ? 6 inches.
E.x. 3. — Required the flow of water through a pipe 2000 feet long, 13 inches
in diameter, and with 200 feet head. For the maximum horse-power we have
(aoo)"- 555(1.0^)=
(3.4)0.555
: 0.864 cubic ft. per second,
ELECTRICITY AND WATER-POWER. lOJ
and
H. P = 2.466 (2O0)'-555(l 08)2-694 \ = 12.373.
(20O0)°-555 -"-^
Ex. 4. — What would be the loss of head in pumpinc; 2000 gallons of water
per minute through an 8-inch pipe 600 feet high? Q = 4. ,(4, and h = 47.6, or
38.3 feet, according to the equations employed.
Ex. 5 — What horse-power is consumed in overcoming friction in the
previous example ? Assume A lo be 38. 3. ig.4 h. p.
The flow is 4.44 cubic feet per second, and the horse-power is O.H34(?//.
Ex. 6. — Whdt horse-power will be given out by the discharge of 400 cubic
feet of water per minute out of a pipe of 13 inches diameter, 2600 feet long,
with a head of 400 feet ?
The loss of head is 32.53 feet, and the h. p. available is 276.
The student is referred to the following recent publica-
tions upon electric and hydraulic transmission of power.
Amfr. Inst. M. E.: Electricity in Mining, F. O. Blackwell, XXIIl.
399; A Twelve-mile Transmission (single phase), T. H. Legget, XXV.
315, The Electric Motor in Mining Operations, George W. Mansfield,
XVI. 851 ; Electricity in Mining as Applied by the Aspen Mining and
Smelting Company, Aspen, Colo., M. B. Holt, XX. 316, Mining Power
Plant. Hydraulic, Comstock, Nev., R. P. Rothwell, XVII. 558; The
Electric Motor in Mining, George W. Mansfield, XVI. 851 ; The
Present Status of Electric Transmission, Rich. P. Rothwell. XVII.
555; Electric Transmission in Mining, H. C. Spaulding, XIX. 258,
Electric Transmission, M. B, Holt, XX. 316; Electric Transmission, F.
O. Blackwell, XXIII. 400; Enumeration of Electric Plants m Rocky
Mt. Region. I. Hale, 1897.
///. Min. Inst.: Electric Wiring of a Mine, i, 267.
Trans. M. i^ M. Eng.: Electricity Efficiency, tests and data, A.
Siemens, XLIV., part 2, 205.
Coll. Eng.: Mining Power Plant, Hydraulic, Maltbv Coal-mine, Pa.,
W. Jones Davis, Feb. 1897, 281 ; Electric Problems in Mining, Dec. 1896,.
217; Progress of Electricity vs. Compressed Air, G. E. }. McMurtrie,.
June 1897, 505; Electricity Power, Water Power and Regulation, edi-
torial, Nov. 1895, 81.
Mineral Industry : Electricity in Mining, T. W. Sprague, IV. 789;
Electric Transmission of Power in Mining, T. W. Sprague, III. 669.
Amer. Mfr.: Electric Power in Mines, Essen, largest plant in the
world, Wm. Clifford, Mar. 1897, 408.
Min. &^ Scien. Press: Electric Transmission at Ogden, Utah, C. K.
Bannister, July 1897, 76; Electricity vs. Compressed Air at Rouse,
Colo., Nov. 1896, 444.
Franklin Inst. Jotcr.: Electric and Heat Energy, C. J. Reed, July
1896, I ; Electricity vs. Compressed Air, haulage, H. Haupt, Feb. 1897,
119.
Coll. Gitard. : Distribution of Electric tor Mechanical Energy, Syd-
ney F. Walker, Mar. 1897, 502; F^lectric Conductors. Svdney F.
Io6 MANUAL OF MINING.
Walker, July 1896,66 and 161 ; Electric Light and Power in Mines, serial,
Sydney F. Walker, LXXI. 18 to iii i ; Electric Light and Power in Mines,
Sydney F. Walker, 1895, 741, 875, 1029, 1069, 1167; Electric Trans-
mission and Haulage, Herr M. Dickniann, Dec. 1896, 1154, Fire Attrib-
uted to Electric Currents, 1897, 283; Causes of Failure of Electric In-
stallation, Aug. 1897, 327; Application of Electricity to Coal-mining
Operations. Frederick J. Piatt, 1897, 397; Accumulators, Electric Power
in Mines, Sydney F.Walker, April 1897, 717; Electricity 7^.5. Compressed
Air in Mines for Power, Jan. 1897, 82; Precautions in the Use of Elec-
tricity. Julv 1896,
Coll. Mgr.: Electric Resistance and Conductors, G. Fletcher, 1894,
35; Electric Motors, G. Fletcher, 1894, 34; Electric Transmission, G.
Fletcher, 1894, 35.
Eftg. Mag.: Electrical Development, Practical and Impossible, Wm.
Baxter, Oct. 1896, 1 13.
Mineralogist's Report : Mining Power Plant, Hydraulic Transmission
Plants, California, 13th Report, 673; Water-wheels, F. F. Thomas, 8th
Report, 785 ; Electric Transmission on the Comstock Lode, 8th Report,
797.
S. of M. Quart.: Principles of Electric Distribution, F. B. Crocker,
serial, Jan. 1897 ; Electricity for Mining Plants, Edward D. Self, XVL 68.
Re%nie Universelle : Electricity, Continuous-current Calculation, C.
Blanchart, May 1896, 113.
Scientific Quart.: Difficulties in Electric Mine Installations, Percy
Williams, Mar. 1893, 38.
Fed. Inst. M. E.: The Practical Transmission of Power by Electricity
and its Application to Mining Operations, D. Selby Bigge, III. ; The
Best Means of Conveying Electricity in a Fiery Mine, A. W. Bennett,
VI. and VII. ; Electrical Transmission of Power, Alexander Siemens,
VIII. ; The Design, Efficiency, and Application of Electric Motors
for Transmission of Power, W. C. Mountain, IX.
Cal. State Mining Bureau: Electric-power Transmission Plants in
California, W. F. C. Hasson, 13th Rep., 1896, 673.
Eng. Soc. of IV. Penna.: Possibilities of Electrical Transmission and
Distribution of Power in Pittsburg, L. B. Stillwell, II. 300; Systems of
Electrical Distribution, Charles F. Scott, X. 3 ; Electric Distribution. W.
G. Wilkins, March 1897.
E. &^ M. Jour.: Cost of Power Transmission by Electricity, Gisbert
Kapp, LVI. 501 ; Sizes and Weights of Tubing, O. J. Edwards, LVIII.
387; Electric Measurement, Bill to Define Units, LVIII. 152; Electric
Transmission of Power for Mining, LVIII. 176; Electricity Applied to
Mining, G. Corlett, LIX. 271 ; Log Dam for Mining Power Plant, hy-
draulic, R. G. Brown, Nov. 1896, 509.
CHAPTER VI.
HOISTING OPERATIONS.
21. Hoisting-derricks, construction of; essentials for strength and
safety; overwinding, and the devices for preventing the same ; indi-
cators, and the modes of communication with the mine. 22. Calcu-
lation of the strains in hoisting-frames; constructions in iron and
wood ; sheaves and their importance. 23. Calculation of the hoisting-
capacity of a mine or shaft ; hoisting-velocities under different
conditions of timbering; loading and unloading conveniences; for-
mulae and examples ; work of the engine in hoisting; definitions of
horse-power, indicated, theoretical, and calculated; formulae; ex-
amples.
21. The most important surface feature is the frame, " head
gear," or " derrick," which affords the skilful constructor ex-
cellent opportunities to satisfy the two necessary conditions,
height and strength; the first for security against overwinding,
the second is fundamental.
It is obviously essential that the sheaves on the frame
should be placed at considerable height above the ground, to
allow sufficient margin within which the engineer may stop the
hoist. With the present high speed and large drums, the
allowance should not be less than the length of one drum coil
of rope, for in a moment's hesitation, or error in the interpre-
tation of the signals, carelessness in signalling, or a derange-
ment of any appliance, the tub or cage maybe dashed through
the roof before the engine could be stopped. Ordinarily, a
brakeman at the mouth of the shaft, having charge of the
delivery and receipt of the cars to the mill or dump, may, as
the cage approaches the top, signal to the engineer, or the
latter may have to depend upon his own watchfulness. So,
107
rf^h^^j^
HOISTING OPERATIONS.
109
devices for preventing overwinding are more or less adopted.
But, while desirable, they are not satisfactory. The number of
Fec. 38.
casualties are reduced by their use, but they are not wholly
prevented. The principle consists in automatically detaching
(Figs. 35, 36, and 37) (ice-hooks open and free the cage) or in
cutting (a pair of shears cut the rope) the cage from the run-
no MANUAL OF MINING.
away rope, when it has reached a dangerous height, and simul-
taneously throwing out landing-dogs, to catch the falling cage
or tub. Or, another plan is to have the guides incline slightly
inward. Then the cage, in its ascent, gradually wedges tighter
and tighter, and this acts as a brake to the engine. Again,
self-acting steam brakes on the engine are constructed so as to
operate when the cage reaches a certain point in the shaft
Eternal vigilance is the price of safety, and the only safeguards,
after all, are a competent and sober engineer, with machinery
in order, a good indicator, and an unobstructed view of the
shaft. If the last-named is not possible, a cool, competent
brakeman at the platform is indispensable. One device sug-
gested appears to be eminently worthy of introduction,— a lo-
ton weight hanging, like Damocles' sword, by a thread, over
the engineer in charge, to be dropped when the overwinding
has reached the fatal limit.
The same may be said of other forms of safety appliances,
even those required by law. They may remedy evils aimed
at, but introduce others. First, too great a feeling of security
is induced, and negligence results. Second, when the emer-
gency arises, they are rusted or out of order and fail.
The position of the cages in a shaft or slope is ascertained
by indicators. An index, operated from the drum shaft by
gearing, rope, or worm and screw-wheel, moves around a dial
or along a miniature representation of the shaft, at a speed
commensurate with that of the cage or tub (Fig. 2 i). A cylin-
der has 15 or 20 turns of a spiral thread cut on its face; a
pointer moves vertically in the thread as the cylinder revolves,
accurately indicating the position of the cage (Fig. 23). The
more trustworthy ones are so geared that the index moves
faster as the cage approaches a landing stage. A glance suf-
fices to inform the engineer, who need not fear overwinding
if brake and throttle are in order. White marks or rags tied
on the rope are useless, as also the attempts to make the cage
automatically signal its warning to the engine-room.
The safest and most natural means which suggests itself
for communication between the engineer and the miner is the
HOISTING OPERA TIOXS. I 1 1
voice, with or without the intervention of the speaking-tube.
The telephone or annunciator is more convenient. Then nns-
interpretations can be excused onl\' by sudden death or crim.-
inahty. The clumsiest and most unreliable signaling arrange-
ment is the gong-bell or triangle, which is struck By a weighted
lever, operated from below by a rope or wire. Its simplicity
commends it, while its crudeness condemns it. Mistakes do
so readily occur. A stroke of the bell may be lost by too
light a pull ; or an engineer, anticipating two bells to lower,
may not await the completion of the signal, and lower before
he has heard the third bell, meaning, perhaps, " hoist with a
man on." If a simple uniform code of signals could be agreed
upon and adopted by mining men, a great advance would be
made. A man formerly accustomed to hoist for one bell, will
do considerable damage in his new job, where one bell means
to lower. See code on page 545.
On page 108, Fig. 40, are illustrated the various measures
for increasing the safety of ascent from and descent into mines.
In No. 4 is Walker's safety attaching-hook, in which a
loop encircles the hook and is bound by it to two copper
rivets which are sheaved when the hook is down. The jaws
then open and release the rope, locking the suspension-jaws
on the disengaging-plate.
No. 2 is the Omerod's, and No. 3 Middleton's hook
operating on the same principle.
Nos. 5,5, illustrates the "Visor," an automatic regulator
of the hoister whereby the brake is applied and the steam
shut off if the engine-speed is excessive at the end of the
hoist.
No. 6 represents " blocks " or "stops " of two pieces of
wood at right angles to one another moving on an upright
pin, one arm being thrown across the track to hold the car in
place until it is released.
No. 7 is a balanced block, the end, b, of which stops a
runaway car on down grade.
No. 8 is the Mortier safety-catch, consisting of an axle
with levers attached, placed in the axis of the roadwav and
112 MANUAL OF MINING.
supported upon sleepers. The axle is movable, and in one
position is opened by the rising car, but in the other closes
after the train passes.
No. 9 shows an arrangement dropped from the roof by
a wire to stop the runaway cars on the incline.
No. lO is a similar appliance with a weighted lever.
No. I I automatically controls the delivery of cars in and
out of the cage, and serves in the intermittent delivery from
incline planes or platforms, without the need of attendants
to release the cars.
No. 12 is a safeguard placed at the foot of an incline.
No. I 3 is a Callow's safety clutch, which is not dependent
upon the breaking of the rope to throw it into action.
No. I 5 is a falling cage-rest or stop which is operated by
a system of levers to release the cage and allow it to be
lowered into the mine without a previous lift, as is the case
with other cage-keeps.
No. i6 is another form of cage-stop described in Gliickauf.
22. The strains to which a derrick is subject are those
arising from the weight of the conveyance, its contents, and the
rope and friction operating vertically, and the pull of the
engine on the inclined rope, which is greater than the weight,
by the amount of frictional resistances at the sheave. This
latter may be taken as 4 per cent, of the weight. These com-
bine to produce a resultant operating in a direction nearly
bisecting the angle between the two ropes, and equal in inten-
sity to about twice the inclined strain, multiplied by the cosine
of half the angle between the ropes. A single stick of sufificient
size may be placed in this direction, and used as a gin-pole for
hoisting; but it is not stable, and, instead, should be a frame,
the base of which shall embrace within its parallelogram the
line of the resultant. The more nearly central this line falls,
the more stable the structure, but the brace then becomes long,
and its section large. Still the engineer will prefer an increased
stability to a slight saving in material, and hence will allow
an angle of about 60° between the ropes.
The form of the frame is essentially two right-angled tri-
HOISTING OPERATIONS. II3
angles (Fig. i6), the brace and upright being nearly parallel to
the rope. They are set into cast-iron shoes, bolted to the sill;
sometimes the posts are tenoned or dovetailed into it. The
top frame is slightly narrower than the base, which consists of
a sill on each side, connected by three cross-sills mortised and
dovetailed to them, the whole bolted and anchored to heavy
" dead men " buried in the ground. Their risk of fire, the ex-
posure to weather, the worlving of the joints, and the difificult)-
of securing sound, long, large sticks, render the adoption of
other material than wood highly necessary. Wrought-iron is
much used. Height is the essential feature of derricks, but
this, with stabiUt)', is difficult of attainment without a rigid
frame, perfectly made. This can better be secured by the use
of Phoenix or Kellogg columns, set in cast-iron shoes bolted to
heavy masonr}' pillars, Firr ^2, nr by well-tied timber. Fig. 41.
Greater stability can be secured for the sheave, b)' building,
of wood or iron, a framework of four vertical posts at the four
corners of the hoisting compartments, suitably braced and tied
with struts from the top, inclined slightly less than the result-
ant force, the lower ends being stepped into masonry pillars,
or joined to a substantial base frame. Fig. 36 is an example.
Upon the top of the uprights is mortised a frame support-
ing the sheave with its axle horizontal, and its unsupported
length as short as possible. The diameter of the sheave should
be 100 times that of the wire rope (48 at least), owing to the
rigidity of the rope, which resists bending. To minimize this
resistance, the wires of the rope are as fine, and the angle of
the bend as small, as obtainable.
This is more imperative as the speed of hoist increases, and
not uncommonly sheaves are seen 12 feet in diameter. All
pulle\'s over which the rope bends more than 30° become, to
all intents, sheaves. The hubs are double, connected to the
cast-iron rim by wrought-iron rods let into sockets, and they
siiould be as light as practicable at the rim, because, by reason
of the impetus tlies' acquire, the)- continue to run long after
the hoisting has ceased. Often the sheaves are cast in sectors,
afterwards bolted together. The grooves are lined with wood.
HOISTING OPERATIONS.
115
on end if possible, and tarred hemp to prevent slip ; for the
transmission of power, with rubber.
Never house the derrick, especially about collieries, for, in
the event of a fire it becomes a draught-chimney (Fig. 42).
Fig. 42.
23. As the mining engineer ma)' find himself compelled to
calculate the plant required, we will briefl}' consider the condi-
tions and the process. The output of the mine depends upon
the time occupied in each hoisting-trip and the load carried,
assuming that the conveniences for delivering to the shaft tit
the bottom, and the facilities for the disposal of the ore and
its carrier, are equal to, if not greater than, the hoisting capa-
city. The speed of hoist is limited by the equipments of the
shaft, which must be timbered very substantially to permit
Il6 MANUAL OF MIMING.
rapid hoisting. Cages are being hoisted in vertical shafts, at
rates up to 2500 feet per minute; skips and slope-carriages at
1,000 feet ; and buckets at not over 300 feet per minute. The
time allowed per trip must also include the arrangements for
loading and unloading. The time lost in filling an attached
bucket at the bottom, and dumping it at the top, is from three
to five minutes; if the empty buckets are immediately replaced
by full ones, much less at both ends. A car can be run on
and taken off a cage or slope carriage in twenty-five seconds.
A skip occupies from two to three minutes to side-track, unload,
and return. The influence of this loss of time can readily be
calculated.
Let t = the minutes to load and unload ;
D = the depth of the shaft in feet ;
V = velocity of the hoist per minute ;
v' ^ " " lowering *' " }
n = number of trips per hour ;
7"= minutes per round trip ;
Q = output tons per hour ;
q = load tons per trip ;
T D D ^
60 '■-''
Dv -\- Dv -\- 2 tvv'\
qn = Q.
Various transformations may now be made according to
the known conditions. Usually q is given, and it is desired to
ascertain 0.
Thus, in a poorly timbered shaft, if only one bucket be run up and down
without detaching, the output from a 300-feet shaft is about 3.6 tons per hour.
With 3 buckets in constant use, each holding 600 pounds, the hourly product
cannot exceed 6 tons. With excellent timbering, double the speed may be per-
mitted, in which event 3 buckets will deliver 7.2 tons per hour at the surface.
So it is evident what a large proportion of the time m^ybe
lost at the landings, when even the doubling of the speed only
increases the quantity one fifth. Skips loaded from shutes
are almost as wasteful of time. Hence, for large mines, cage
and cars are resorted to. Then, from the 3000-feet level, 36
HOISTING OPERATIONS. WJ
tons may be lioisted per hour, by three cars in constant use,
holding each 3,000 pounds, and assuming a not uncommon
rate of 1,800 feet per minute.
The size of the engine must necessarily depend upon the
velocity of the hoist, the load, the dead-weight of the rope,
case, car, etc., and the various resistances. Unless there is a
counterpoise (see p. 90), the maximum work of the engine is
at starting, when tlie inertia of the load, M, is to be overcome.
R = the weight of rope per foot ;
B = weight of bucket, car, cage, etc.
Then M = 20O0q -\- RD + B.
The resistance of friction, etc., is about I2 per cent with cage ; 4 per cent
with buckets ; and 20 per cent with skip. Therefore the value of M is greater
than that given by 4, 12, or 20 per cent, as seen ; and equals
1.04, 1. 1 2 or 1.20 times (.5 + RB -\- 2,0005/).
Though the load, M, is not operating throughout the hoist,
it is necessary to have sufficient power to start as quickly as pos-
sible, without jar. Moreover, a force nearly twice M is re-
quired to overcome the inertia of the load. So the allowance
is made as indicated, thougli it is indeed too small for the
initial stages of the hoist, and too great during the final.
The work done is always a product of the resistance HI,
(the strain on the rope) and the velocity per minute, the horse-
power, H, being found by dividing by 33,000.
Tlius we require theoretically 754 horse power to hourly
raise 36 tons from the 3,000-feet level b\' a cage and car weigh-
ing 2,300 pounds and rope. With a tapering rope, 150 horse-
power may be saved. With double c}'linder drum, two cages
and cars, the same product may be raised at 1,300 feet per
minute, and o)ily 430 horse-power needed.
The term horse-power of an engine has a three-fold inter-
pretation :
1. The indicated horse-power, wherein the actual work
done is measured by an indicator, the friction by a dynamo-
meter.
2. The theoretical, which is the product of the boiler pres-
sure, the area of the cylinders and the piston speed per minute;
Il8 MANUAL OF MINING.
the losses from imperfect delivery of steam, friction of valves,
etc., clearance or compression are not considered.
3. The calculated horse-power is a certain fractional part of
the theoretical, found by multiplying the latter by a modulus,
m, which allows for the losses mentioned as well as for the inter,
mittence in running. The value for ;« varies from 0.60 in a very
poor engine to 0.90 in one in good working order.
If J = the length of piston-stroke in inches; k = the diameter of cylinders in
inches; N = the number of revolutions per minute; o. ibbA^s = the piston-speed,
feet per minute; f = the number of cylinders; _/"= the coefficient of friction;
p = mean effective steam (gauge) pressure, pounds per square inch; P = steam-
pre'isure (gauge) on entering the cylinders; H = the horse-power actually being
performed by the engine, — then
252100 V 2 I I /\ I y I „^ _ ^^^
r rom this latter equation it is possible to calculate the depth
to wiiich a given engine will do service, for all the quantities are
known, or may be assumed, except D. which is then calcu-
lated. See examples.
With a plain slide-valve engine using steam throughout the
entire stroke, the boiler-pressure may be substituted for/ with-
out sensible error. If, however, the indicated horse-power is
measured, both H and / are very accurately known. It must
be remembered that the above gives only the approximate work
of an engine, without considering the influence of the masses
ot the rotating and reciprocating parts. Generally speaking,
thv,' heavy revolving pieces tend to equalize the speed of the
engine and the load ; but the var3'ing angularity of a short
connecting-rod influences the rotation of the crank-shaft in
such manner that it is faster during the first part of the out-
ward stroke and the last part of the return than during the re-
mainder of the revolution. In like proportion, the crank-pin
receives a varying rotational effort which is nil when the
piston is at either end of its stroke, and a maximum at some
certain point about 80° to 100° from this.
For engines in constant duty, the inequalities may be cor-
HOTSTIAG OPERA TIONS.
119
•rected by a sufficiently heavy fly-wheel without any material
loss of work. In lieu of a fly-wheel the hoister has the inertia
of the drum ; and the greater the drum, or the length of the
connecting-rod, the more uniform is the velocit)'.
Hoisters, moreover, as stated on p. 66, must be capable of
starting from any point of the piston-stroke. To be assured O;
starting the load as well as keeping up the velocity, the hoister
is built with two cylinders having their cranks set "at quar-
ters," as mentioned on page 74. To determine the conditions
of equilibrium by moments, it must be remembered that the
pendent weight M, with its lever-arm equal to the half-diameter
of the drum, r, is to be in static equilibrium with the sum 01
the rotational forces on the two cranks multiplied by the crank-
arm (one half the piston-stroke).
To facilitate calculations the following table has been com-
puted. It gives a coefficient, C, representing the maximum
and the minimum moments for duplex engines with various
expansions and ratios of connecting-rod, /, to crank-arm, a.
The calculations are made on an assumed clearance of 7 per
cent. T\\&nCsPk'm = {M^Mf)r.
Apparent Cut
off.
/ =
4 5(1.
/ =
S-S-^-
/ =
^a.
0.00
0.5615
0-3974
0. 5600
0-3974
0.5580
0-3974
\
4664
3633
4606
3688
4586
3696
\
4380
2472
4365
2499
4353
2550
\
4256
1878
4193
1923
4124
1966
\
3893
1469
3818
1473
3786
1512
Cog-geared, second-motion hoisters may be calculated sim-
ilarly by introducing the proper coefficient, C, in the following
formula, where x and j/ are respectively the number of teeth in
the pinion and drum-wheels :
CsPk'ym 3= M(i + f)rx.
The data given here may serve as a guide for shaping the
engineer's opinion as to the hoisting capacity required. The
fcillowing carefully compiled tables may assist in illustrating
the benefits derived from the expansive use of steam. The
first column is the ratio of expansion (the ratio of the volume
finally occupied by the steam to that at the moment of cut-off),
I20
MANUAL OF MINING.
assuming a piston clearance of 7 per cent of the cylinder ca-
pacity ; the second gives the corresponding period of cut-off ;,
next is given the average mean total pressure (absolute) on the
assumption of perfect expansion in accordance with Boyle's
law ; the fourth contains the total actual work done by one
pound of steam at 100 lbs. initial pressure ; finally is given the
consumption of steam in pounds per horse-power of actual
work done per hour.
Ratio.
Cut-off.
/
6.30
1
0.413
5.50
i
0.457
4.50
i
0.527
4.00
\
567
3.35
1
4
0.b37
2.65
4
0.726
1. 88
i
0.860
1 .00
I
1 .000
Work
per Pound of
Steam.
151
370 ft.
-lbs.
146
323 '
138
130 '
132
770 '
124
066 '
112
220 '
94
200 '
5S
273 '
Steam
per Hurse-
power.
13.08 lbs.
13
53 "
14
34 "
14
90 "
16
00 "
17
70 "
21
00 "
34
00 "
No allowances are here made for the results of wire-drawing,
pre-release, or back-pressure. If the steam is not at a boiler-
pressure of 100 lbs. per square inch, the following list of multi-
pliers will serve for calculating the actual hourly performance
of work under other initial pressures with their corresponding
temperatures ;
p
Temperature
of Steam.
Multiplier.
/'
Temperature
ot Steam.
Multiplier.
70 lbs.
302 .9 F.
.9S1
no lbs.
334°.6 F.
I . 009
80 ••
312 .0
.988
120 "
341 .1
I .01 I
85 •■
316 .1
.991
130 "
347-2
I .ors
90 ••
320 .2
■995
140 "
35- -9
1 .022
95 "
324 .1
.998
150 "
358 .4
1.025
100 ■■
327 .9
1 .000
160 "
363.4
1 . 03 1
E-\. 7. — If .f = 48, A^= 40, / = 60, and f = 2, the engine required for ttie
example on p. 117 isone having a cylinder of 28 X 51 inches, allowing for 7 per
cent clearance.
HOISTING OPERATIONS.. 121
Ex. 8. — Required the size of an engine to Jioist looo tons per lo hour shift
from a shaft 1200 feet deep. The cage load being 4 tons, P = lou with a cut-
off of ^, N = 40, and a modulus of 0.80.
Q = 100, / = 0.4, D = 1200, ? = 4.
Let V ^ I 500, then 7" = 24 and n = 25 trips. Whence
M = Sooo -|- 1500 + 800 -|- rope.
If the rope weighs 2 ll)S, per foot, then o.oibisk'' = 646.5, or k is nearly 27 for
.r = 60 inches.
As 1200 feet of rope must be coiled on the drum at a rate of 1500 feet per
minute, the direct-connection drum making 40 revolutions must have a diam-
eter of 12 feet.
Ex. 9 — What load will this engine start?
For a length of connecting-rod of 165 inches (or 5.5r) the minimum co-
efficient is (p. 119)0.1023. whence
0.1923 X 5 X lou X 729 --= 1.12/1/ X 6,
and M = 10,386 lbs. in order 10 start the load of 12,700 lbs. calculated above,
the boiler-pressure, P, should be 122 lbs., or else the engine must be stopped at
a point different from that corresponding to the minimum effort on the crank-
pin. A drum of 59 inches radius would give equilibrium, but then the velocity
of hoist would be reduced to 1236 feet per minute during the early period of the
hoist, though it would gradually increase to nearly 1500 feet per minute.
Ex. 10. — If it be required to know to what depth a given engine will do ser-
vice, the order of procedure is as follows : Substitute in the second equation on
p. 118 all the known quantities, and solve with respect to D.
I^hus, a single 16 X 30 inch engine at 72.6 lbs. mean effective pressure, and
a piston-speed of 300 feet, will give S8 h. p. if its modulus be o.So. Assuming
a cage at 1500 lbs., car at 750 lbs,, and a load at 2300 lbs., M = 4550-(- KD.
If a rope of 1.5S lbs. per running foot be taken, we have
Dn
X 33000 = (4550 + i,58Z:i)(i.i2) .
30 — /;;
If the output is 60 long tons per shift, q being 2300 lbs., then, with / = 0.4.
n becomes nearly 6, because (_' = 6 long tons (13,440 lbs.). Substituting in the
above, D becomes equal to 1704 feet. If ;■ = 2 minutes, D = 1200 feet.
Ex. II. — For an output of 300 short tons daily the same engine will do ser-
vice to depths of 1240 and 829 feet, respectively, under the conditions named
below :
Q =
15 ;
/ = 0. 5 ;
// -
= S ;
and
/■ =
102
lbs.
Q-=
15 ;
/ = i.o ;
// -
= ,^ ■
and
P =
72,0
lbs.
122 MANUAL OF MINING.
In each case 17 is 2 short tons and R = 2 lbs., the car and cage being
assumed at 3000 lbs.
E.x. 12. — It is intended to erect a pair of coupled engines directly connected,
to hoist two cars carrying 3100 lbs. each, a cage weighing 1500 lbs., in a shaft
1800 feet deep, at an average speed of 1000 feet per minute. If the engines
are to be \ cut-off, required their size with a flat rope.
Assume the weight of each car at 1000 lbs. Then the rope supports 9700
lbs. besides its own weight, which is 5 lbs. per foot at the top and fcr 600 feet
down, then 4^ lbs, for each of 400 feet, and 4 lbs. per running foot for the re-
mainder. Each cylinder must be capable of e.\erting 402 h. p. if the modulus
of the engine is f. Let the boiler-pressure be 80 lbs. effective, then the average
pressure is 58 lbs. (p. 120). Each cylinder will be 38 inches diameter and us
piston have an average speed of 200 feet per minute. Suppose the stroke to be
4 feet, then 25 revolutions are made per minute by the crank-pin, and also by
the reel. The smaller diameter of the reel is 30 inches, and the final diameter,
wilh the last coil of rope, is 147 inches. The sizes of the rope are 4f X jj
inches, ^\ X tI' ^""^ 4 X f . If two reels are employed the cages will pass at a
point 1118 feet from the surface.
An engine set to \ cut-off is working under qo lbs, boiler-pressuie. Theo-
retically, it should give 122,220 X 0.995 = 106,609 ft--'hs. of work for every
pound of steam used, and should consume only 17.7 lbs. of steam per hourly
horse-power. If, however, the gear be set to \ cut-off, 131,224 ft. -lbs. of work
are obtained from the same amount of water evaporated and the same fuel con
sumption. This would correspond to a gain of 23 per cent in power.
It is recommended to engineers that they watch and fre-
quently examine the performance of their engine by the use
of the indicator. This appHance is, figuratively speaking, the
stethoscope to an engine, and when the merits of it are once
tested an engineer will acknowledge it invaluable. It is not
sufficient that the engine does not " knock" or that no leal^s
are apparent, for there are many serious causes of loss, such as
too tight stufTing-box, loose piston-packing, bad setting of
valves, restrictions in the steam-passages, wet steam, and im-
proper amount of steam compression, which may be unsus-
pected, and nothing but an indicator will reveal these faults,
which may then be easily corrected. The writer cannot
impress the value of this little machine too strongly. It is
cheap ($30), simple, readily attached, and requires no elaborate
calculations. The results are pictorial. There are a number
of works on the indicator which fully explain its manipulation.
HOISTIXa OPERATIONS. 133
The following references are cited for the use of the
student:
1-ed. Inst. M. E.: On Overwinding and its Prevention. A. Bertram,
I.; Apfiaratus for tlie Prevention of Winding and Overwinding Acci-
dents at Collieries and Blast-furnaces, William Grimrnitt, II.; Remarl
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148
MANUAL OF MINING,
5
DUMP-CAR, BOBTAIL TUNNEL, COL.
Cost SlOO -I-
~mL
Wt. 900-1000 lbs.
Capacity \i curd = 2Tons
MM,
Jll^
' w|n]P
Fig. 59. — Tunnel Dump-cak.
UNDERGROUND TRAFFIC. 1 49
large cars is cheaper, so the tendency is toward a great capac-
ity, though the natural conditions of underground work re-
strict the dimensions. The small cars used in buggy roads (see
p. 34) have a capacity of 26 cu. 'ft., and are made for a 3' or
4' gauge. The length of the cars is limited by the sharpness of
the curves; in collieries the maximum is 9 teet; in
metal mines it is 70 inches. Their lieight depends upon
the conditions of loading. In thin seams and steep veins cars
only run in main haulways, and are filled from chutes, provided
with a spout and gate, easily manipulated at the bottom ; if
also hoisted on a cage, their height is a matter of indifference.
When the seam is thick and the roof good, they are carried up
to the face of the work, in which case they are filled by hand.
If so, or if raised on carriage, the difficulties and expense
are greater with a high car. To shovel one ton into a 3-foot
car requires over 7300 ft. -lbs. ; into a car 4 feet high, 9500.
The average man can exert a continuous shovelling effect
of 28,100 ft. -lbs. per hour. Allowing for the weight of the
sho\'el, delays, throwing the mineral forward, a shoveller maj'
load about 20 and 14 tons, respectivel}-, in the cars per shift.
Even for a medium output the economy is manifest. In
metalliferous mines this is observed, but in collieries cars of
4' 9" and over are common. For stabilit}', too, a low car is
desirable. The \\'i(lth of the car depends upon the gauge and
its " set." ]]road cars are preferable, but maj' not be advantage-
ous because of the wide gauge. Nor are they desirable if set
up on a narrow gauge. A compromise is frequently taken, by
which a low, wide car on a narrow gauge is emplo)'ed. The
axles are elbowed for large wheels, and set down on them is
a narrow body, which bellies out wider over the wheels. All
mine cars should be provided -with bumpers, to keep the bodies
of said cars at least 12" apart.
The gauge varies from 2 feet to 4 feet, \\'ith good and suf^-
cient reasons for the choice of any intermediate. Broad gauge
gives greater stability, and a reduction of haulage-expenses.
The minimum gauge of 2 feet is advantageous for easy haul-
age and sharp curves, cheaper track and rolling-stock, but
ISO MANUAL OF MINING.
tends to reduce stabilit)' and capacity. It reduces the length
of the car, but allows of the use of inside wheels.
The wheels are as large as circumstances will permit (the
larger the wheels and the smaller the a.'^les, the less is the fric-
tion). The wheels may revolve loosel}- on the round or the
square axle, or they may be fixed to the axle and revolve with
it. Some are capped \\\X\\ a recess in the hub, to receive the
collar on the axle, and thus prevent admission of grit (Fig. 56).
They may be " inside " (below), or " outside " (beyond), the
body of tlie car. As to the relative merits of the inside and
outside, or loose, wheels, it must be admitted that engineers
are not united in the opinion, though the former has the larger
number of adherents. Outside wheels are more easily oiled,
are cheaper and admit of the body of the car being set lo«"er
down ; they do not run so smooth, or last as long as those
fixed under the bod)' of the car. Loose-wheel cars may be
better for short roads with sharp curves, but they are harder to
pull. With fixed wheels, one of the mutualh' dependent
wheels, in travelling about curves, must slide. For this reason,
and the ease of lubrication, loose wheels, or cone-fixed ^\•heels,
are preferred b)- man)-. The U. P. R. R., 3 feet gauge, aban-
doned loose wheels after careful trial. At the Drifton anthra-
cite mine, a compromise is effected by using a pair of fixed and
a pair of loose wheels.
The coal-car wheels are of cast-iron, between 16 inches and
18 inches diameter, and those of ore-cars about one half that,
and solid ; while the former have hub and arms to allo^v of
" spragging."
Coal-cars are fixed on two trucks, and dump from the end,
being provided with a swinging door (Fig. 54). Iron-frame cars
are more commonly provided with a swivel and a lever, which
hoolcs or unhooks the body from the trucks (Fig. Go). Dumping
is easil)' effected by opening at the side or end a swinging
door hung on an iron rod across the top by two hinges (Figs. 61 ,
62, and 63). Another variety of car in use in tunnels consists
of a double iron-framed car, pivoted together at the centre top
of each side, on two trucks. In dumping, the latch-lock on
UNDERGROUND TRAFFIC.
iSi
<-_-;^
«'
-r
\^
■^■
.^ 1
No
i Iron
\
i
■4->
r\i^"^
2THUS
^^■.i-
!#'
2 THUS
2i!«-
7^
iPiSiM
iKej-
-IX
^Kough
1 THUS
Rougrli-, -
r-K Key
r»i
-^H
•■^
1
n
iii
<
(
H '>t
^
^
2 THUS
1 THUS
Bi:
Fig, 64.
152
UNDERGROUND TRAFFIC.
153
each side is raised, the car opens in the middle and empties
between the tracks (Fig. 59).
Often the dumping is accomplished at the surface by some
automatic device, consisting of a balanced frame, or pivoted
cradle, upon which the loaded car is run and held. The moment
its centre of gravity is beyond the point of support, it tips and
empties the car. In another type of the dumping cradle,
the entire combination is inverted ; the car, which is held, dis-
154 MANUAL OF MINING.
charging its load at once. Behr's device is of this character
and is represented in Fig. 65. This permits the use of a
stronger and hghter car, and dispenses with a dumping device
on the car. A similar idea is adopted in the construction of
the cars, without the use of the cradle. The body of the car is
hung on a horizontal axle over the truck, so that the centre
of gravity of its contents is very near to the fulcrum. ; a very
Fig
small effort by the trammer will tip the car after it is unlocked.
As much attention shoLild be given to even the most insig-
nificant details as on surface roads, to secure maximum econ-
omy ; rigorous examination into anti-friction method is advised.
Bearings and axles should be readih' accessible. Self-oilers
can be had, simple and cheap. Thej' save power and reduce the
wear. By their use, one-third of a pint of oil will last two to
four months, according to tlie qualit}' and the distance traversed.
Their addition, in one mine, saved %j per year per car, in oil
and grease. Another example, as a corroboration, taken from
an ordinary trip, sliowed that a locomotive can haul 2C cars
with plain wheels, with a loss of 12 pounds steam-pressure,
against 28 cars with Bowdcn self-oilers and a loss of only 3
UNDERGROUND TRAFFIC.
IS5
pounds. The oils used for lubrication and illumination, under-
ground, in the Lake Superior mines, are let down into the
mine through a small pipe into tanks, instead of lowering the
barrels.
The haulage inclinations and velocity being slight, brakes
Fig. 65.
are not needed, nor are they much used, unless the stout stick
with its fulcrum under the body of the car, and pressed on the
wheel face by the weight of the trammer at the other end, may
be dignified hy the name. In coal mines, "spragging" is
resorted to, and is more effective. A sprag is a billet of wood
12''' long and 2" thick, wliich is deftly thrown between the arms
156 MANUAL OF MINING.
of the wheels and prevents them from turning, and converts
the car, more or less, into a sled. On a slight grade only one
sprag may be required, while on a slope of i in 6 it takes 4
sprags to check the speed of the car. They are of no use on an
incline of over i in 5, the angle of sliding friction. Roads are
often designated as i-, 2-, 3- or 4-sprag roads, by which is meant
the number of wheels spragged.
To prevent accidents from runaway cars on a grade, or
from the mill back into the shaft, automatic devices are used.
They are usually a balanced timber block automatically thrown
across the track before the car reaches it, temporarily blocking
the way. See Fig. 40.
The life of a car depends upon conditions too varied to
state here. Wooden cars become loose, shaky, and larger
with age. Iron ones are battered and bulged, particularly if the
mineral is in large lumps.
29. The tramway is of T rails, weighing in rooms, 12 pounds,
in gangways and levels 16, and in slopes as high as 35, per
yard. Very light rails are not economical. A broad rail
favors the wheels ; depth and weight give stability. Only in
petty mines does the strap rail survive, and in some steep slopes
the wooden strap. The cost of I mile of 16-pound rail, laid,
is $1600 (steel at $33). If the floor of the gangway is uneven,
the sills or sleepers are laid on the knolls or ridges. For
heavy duty the gangway is double tracked, or, sometimes, a
single track is laid with suitable turnouts and plain frogs. At
junctions, a simple iron turn-plate laid on stout planks is used,
instead of the more elaborate frogs and crossings. The men
drao- the end of the car around, and shift it to the desired
track, when it is run off. Self-acting switches are not in favor
The opportunities for economj' in underground work are
not many, for the conditions are necessarily proscribed.
Mechanical appliances are difficult of application, and particu-
larly so in veins of high pitch, where the inconveniences in-
crease, because of the narrowness of the gangway. Other lines
of economy are easily obtained, and the virtue of well-laid
track specially commended. On level surface roads, the trac-
UNDERGROUND TRAFFIC. 1 5/
tive force required to overcome friction is about I per cent of
the load. Underground it is rarely less than 3 per cent.
R. Van A. Norris, Wilkesbarre, conducted an elaborate series
of experiments, with the result that the coefficient of friction
was rarely less than 60 pounds per ton, occasionally kX)
pounds is reached. With self-oilers this was reduced to i-^-
per cent. With any mode of rope haul, the frictional loss of
power may and often does amount to 40 per cent of the weight.
There is no reason why the same care should not be employed
below as above ground.
The difference, in the cost and time of laying, between a
substantial track and one poorly laid is trifling, but in effi-
ciency is astounding. One car running two-thirds of the
year consumes, per ton of mineral it carries, on the latter, an
equivalent of 30 tons of fuel more than it would on a decently
laid road, and the amount that an animal or a locomotive
can pull is reduced to a quarter of that on a good road. Per-
haps it may not be regarded as essential; it is nevertheless
advisable that good workmanship be expended upon the track-
way and rolling-stock. This is more urgent as the output is
large or its value small.
For a small turnout, or on a short level haul, man power
may be employed; but, as any of these increase, power must be
invoked. For steady tramming, the average man is capable of
exerting 27 pounds push, at 2 feet per second, moving a 2-ton
car on a level, and making, according to the condition of the
roads and the running-gear, from 3 to 12 ton round-trips of
one mile.
Under like conditions a horse or mule makes three single trips
with from 4 to 10 tons gross load per hour: though the delay's,
friction and bad air reduce the average to 40 or 50 gross ton-
miles per day at 4 or 5 cents. The utility of the animals is
confined to haulage in the secondary ways, the rooms, and for
switching-places where economy in height is practised. This
gives the mule a superiority over horses, because it is not so
tall, though equally strong. Even as it is, the roof must be
ripped off from beds below the standard thickness, to admit of
158 MANUAL OF MINING.
a gangway high enough for mules; often, dogs or pushers are
employed instead.
Usually mules are driven in teams of from two to six, accord-
ing to the length of the trip and of the train, averaging two cars
to the mule. Their ordinary speed is about two miles per hour.
Some small mines employ them for haulage from working
breasts, or only from the secondary ways, to daylight. In larger
properties the mule never again sees daylight, and travels be-
tween the rooms and the general parting, or even only in the
branch roads. Except where there are numerous ventilating
doors to be opened and closed, or many sharp turns to be
rounded, there are few cases in which the mule has the advan-
tage over mechanical means, and where the railway may not
be extended throughout the entire workings without great ad-
ditional expense. It is the privilege of the operator to replace
animal power b}' machiner}?, and just in proportion as he
avails himself of the latter, so will his profits be.
The average cost of mules is about the same as with horses.
It takes thirteen animals to supply ten workers, the balance
being on the retired list for various causes, This excludes
the allowances for death by accident. The cost of their keep
is go cents per day. The accommodations for stabling need
not be expensive, but attention must be given to ventilation
and cleanliness. Under average conditions one mule will
serve for the haulage of an output from ten miners.
About 9000 gross ton-miles per year represents the work of
one animal, which, however, varies with the grade and condi-
tion of the track. The limit is determined by the tonnage that
an animal can return with uphill. Onl)- a small grade is admis-
sible, and that, too, from the breast. The maximum is some-
where near 3 feet per 100. A gradient of equal resistance
(that on which the work on a loaded car down equals that on
the returning car) should be provided where possible. If the
empty returns with stowage and supplies, the grade of its track
should flatten as their weight approaches that of the mineral, as,
otherwise, the duty of the animal is lowered appreciabh'. A
power which will pull 100 tons on a level can take only 47 up
UNDERGIWUND TRAFFIC.
IS9
so slight a grade as 20 feet per mile, and 25 and 13.5 tons re-
spectively on a I per cent and 2 per cent incline.
It is easily understood tliat the de\-elopment of an exten-
sive property by numerous shafts is expensive, so it is likely
preferable to transport the mineral underground even a consid-
erable distance to a shaft centrally located, if this can be done
quickly and cheaply. This invohes the elaboration of a s)-s-
tem of haulage depending upon conditions of grade and
the method of mining, as follows :
1. Where the tramway is horizontal, power is required both
ways by man, horse, locomotive, stationary engine or rope-
wa}'s.
2. If its grade is towards the shaft, the full train down pulls
an empty up, on a self-acting plane or tramway.
3. When the grade is reversed, the loaded and empty cars
are moved by a tail-rope or endless-rope arrangement.
The method adopted should not be complex, all the details
carefully proportioned from direct calculations, the positions
of branches and the location of machiner)' comprehensively
planned; often the opportunit}' for obtaining cheap haulage
fixes the entire plan of the mine.
The advantages offered b)' either of these systems cannot
be generally stated. An\- plan allowing of a single track in a
narrow gangwa}' usualh' has the preference, though on a
double way no extra power is ixquired to overcome the friction
and the dead-weight of the con\'e)'ance. Of course the most
favorable tramroad is that affordnig a down-grade on each
track. But as this is not feasible, it behooves the engineer
to diminish the frictional resistances and avail himself, as much
as possible, of the acceleration of gra\'it3-. Power other than
gravity is indispensable when the grade is low or against tlie
loaded car. Stationary engines cannot be employed under
ground because of the dangers and inconvenience from sparks
and exhaust steam, unless air be the motor fluid. Steam-,
pneumatic-, or electric-locomotive or rope traction is then
necessary.
l6o
MANUAL OF MINING.
30. The locomotive furnishes a cheap haul for great distances
and large output (Fig. 66). Its simplicity and convenience re-
commend it to favor; it is much cheaper than animal power,
and has the advantage over it in times of strikes and loclcouts
(it has not to be fed) ; it is easily accommodated to varying de-
mands on it. As it is usually coal-burning, the gaseous prod-
ucts turned off into the mine justify the outcry against it.
It befouls the ventilation, introduces a risk from fire, and also
elements favorable to the decay of the roof and timbers, — heat
and moisture. Its passage up and down interferes markedly
with the volume of air traversing the entry ; when the loco-
motive travels with the current, 20 per cent more air passes
through than while travelling against the current. On this ac-
count the ventilating current should have a greater speed
than the locomotive. However, its gangway is usually cut off
from the general ventilation of the mine, the inlet current
being introduced beyond the inside terminus of the locomotive
run. The cost of these improvements, preparatory to this in-
troduction, is no small item ($7000 in one mine).
Still, to a large extent, much the same objections obtain to
any underground steam-engine, compared with which its
greater haulage velocity results in less cars for equal tonnage,
and less cost (2 cents per ton-mile). On the other hand, it Is
useless on grades of over 3.5 per cent.
Compressed air may be used for the power, instead of
steam, and afterwards for ventilation. If this is done, station-
UNDKKGKOUND TRAFFIC.
i6i
ary engines will have the advantage over locomotives ; other-
wise, all things considered, the latter will ordinaril)' be prefer-
red ; and it is remarkable what dry steam they furnish, and
what work they accomplish considering that their draught
height is limited, the rails wet, and the curves sharp.
The locomotives are made of a shape to suit the mine open-
ing, for narrow gauge (36" to 40") raiely over 78" high, have
four to six wheels (for curves of 50 to 75 feet radius), weigh 4
to 13 tons, and carry 125 to 350 gallons of water. Their cylin-
ders are from 5 X 10 to 10X14, on 22" to 28" drivers, running
over 16 to 28 pound rails, and costing $2,600 to $4,000. They
have a traction of from 150 to 600 tons on a level. There is
no difference in the price between the wide and narrow gauge
locomotive of the same design and size of cylinders.
-'^^^
FiC. 67.
The hauling capacity (the total weight of train guaranteed
to be hauled on a level, straight track) is limited by the adhesion
of the drivers to about one third the weight of the locomotive.
A locomotive with a pair of cylinders 6" X 10" will, on a grade
of 105 feet to the mile, haul 28 tons of train 20 miles daily on
600 pounds of coal. One of lOX 14, on a 52-foot grade and 50°
curves, has an actual duty of 46 tons, 28 miles per day, with
1000 pounds of fuel. The average grade in mines is about 2
per cent, on which the capacity of the locomotive is 13 per
cent of that on the level. Grades are usually reduced on
curves 0.02" per 100 feet for each degree of curvature. The
daily running expense of a locomotive is $4. 50. Locomotives
with inside cylinders are advised for narrow tunnels only.
i6-
MANUAL OF MINING.
UNDERGROUND TRAFFIC. 163
The tractive force, T, of a locomotive is measured by the formula DT =
o.o654,i''/j, wherein D is the diameter of the driver in feet, and k, p, and s as
in 23. The traction of a locomotive, a static force, expressed in pounds, must
not be confused with its horse-power, which is a unit of dynamic force, embrac-
ing the elements of weight, distance, and time, (Compare with 23.) The
traction, T, must be equal to or greater than the sum of the train resistances ;
I, the frictional, which in mines is not less than 50 lbs. per ton of train, and
equals 0.025 Y \ K is the number of tons weight of train and load ; 2, due to
grade, which is 20^ F, g being in feet per too ; and 3, due to the curve, \ivzU' ;
this is \ lb. per ton per foot width of gauL;e, ;, per 1° curvature ; w is the weight
of the number of cars which are on the curve at the same time ; for substitution,
when the radius of curve, instead of its degree, is known, we have D r = 5,730.
Pneumatic locomotives (Fig. 67) art not )-et successful, nor
the various fireless and smokeless engines constructed to be
operated by volatile chemicals, leaving electricity and the wire-
rope systems as the onh' real competitors of steam-locomotives,
which are confessedly not as economic or as safe machines as
stationary engines.
The signal success of electric installation has led to improve-
ments in haulage methods by the use of morors (Fig. 68) and
storage-batter}'. y\side from other considerations, the rotary
movement of electric appliances admits of a better running
balance than can be given to ordinary- reciprocating engines,
and the)' are therefore less liable to jump the track. An 80-
ampere, 450 volts Compton series wound machine, operating
haulage engines, hauls from three parts of the mine, by cable
3200 yards long, 100 tons per da\-, and replaces 27 mules,
besides se\'eral helpers, etc. As yet electric propulsion is more
expensive than steam, and gi\'es more ti-ouble, because of the
liabilitj'to indefinite dela)' from frequent groundings and other
mishaps peculiar to electricity when carried b)- trollev-wire
a^ in the surface roads. Judging fi'nm the Census Re|")orts,
the interest ov\ tlie big plant is a \"er)- large item in the cost
of electric jjropulsion. The current is carried by a No. O
wire, T- or L-irons being used for the trolley.
A loss of fifteen per cent is usually allowed for the line
loss in voltage froni the generator to the end of tlie run,
and an efTicienc)' of eighty per cent is estimated for the
motor.
lf^4 MANUAL OF MIXING.
Storage batteries obviate the necessity for wires, but are as
yet too expensive. About 25 lbs. of battery will carry one
horse-power per hour. A space of 40 square feet will accommo-
date 250 elements, which will furnish 11 horse-power for a 10-
hour shift. The weight, and hence the adhesion, of this engine
is over twice that of the steam locomotive of equal horse-power,
even if the coefficient of adhesion is not increased.
Where the conditions are favorable to the use of gravit}' as
the sole power, on a self-acting plane, the principle emploj'cd
is to let a loaded car going down pull an empty car up. A
rope connecting the two cars, passing around a sheave, or a
drum, at the liead of the incline, is the only mechanism re-
quired. With the former a single rope is used, while with the
latter two ropes, wound in opposite directions, connect the
cars. The axis of the drum is horizontal ; of the sheave, verti
cal. The ropes are of a length equal to that of the plane.
Often on a drum a single rope is used, which receives four or
five extra wraps to prevent slipping, the ends being attached
to the empty and loaded cars, respectively. This is not
recommended.
The sheave or drum is in a recess fitted for it on or above
the counter gangway, where are received and connected the
cars from the breast, or sometimes this arrangement delivers
direct from the breast ; the terminus is on the lower gangway
or at the foot of the shaft. Swinging platforms connect the
drifts or gangways with the slope. Usuall)' two lines of rails
(35 lbs.) are laid the whole length ; single tracks with turnouts
are false economy.
The smallest gradient at which these are operating is 6° ;
the best, i in 5 ; while on one over I in 3 there is an excess of
fractive force above resistance. At an angle exceeding 35° the
iTiefhod of mining is such as would not afford an opportunity
for tills means of delivery. Occasionally, in steep veins, such
a scheme is in operation for delivery down an "auxiliary"
from the several levels to the main gangway. The surplus
force must be counteracted by a strong brake, which regulates
the speed to a nicety. The mean velocity is about 400 feet per
UNDERGROUND TRAFFIC. 1 65
Tninute, and to diminish the momentum toward the bottom
tlie plane is flattened. The theoretical curve of the slope is a
cjcloid, concave upwards.
The brake is usually an iron strap with wooden blocks, actu-
ated by a lever. India-rubber has many advantages over wood,
though hitherto the trouble has been to fix the rubber on the
shoe, because it disintegrates so readily where the bolts pass
through. This has recently been overcome ; the rubber blocks
have a dovetail at the back, which is inserted and fits easily
into its shoe. The tightening of the blocks on the wheel while
" braldng" crowds the dovetail into the shoe.
Means must be devised for preventing the rope from slip-
ping off the sheave, and provision also made to protect it from
undue strains caused by shocks. A V friction-clip wheel,
designed so that its friction will equal that on the road, is the
simplest plan. The clip bites the rope, and there is no slip or
wear unless a car jumps the track, when the slipping of the
clutch will notify the brakeman. This clip-pulley is also very
effective on endless-rope systems for transmitting power.
The limit of length to which these planes may be used is
fixed onl)- by the friction of the dragging rope. Anti-friction
rollers, 6 X -O inches long, on i-inch axles, are therefore neces-
sary at intermediate points, about 20 ieet apart, to give it
support. The amount handled is limited only by the facilities
and conveniences affecting the trip time. The system is inex-
pensive, requires strict discipline and an ample signalling code.
The cars may be connected singly or in trains, but equally on
each branch. Trailing-forks behind the cars prevent catas-
trophe if the rope breaks — usually it is the up-rope.
These tram\\a)\s are equall_\' good underground — as on the
surface — where the cost docs not exceed 10 cents per mile-ton,
and is often as low as 3 cents (Fig. 69). The cost of construc-
tion is about $3 per foot of length. Smaller sized ropes are
needed than for an equal length and weight of vertical hoist.
Two-car trips on io° planes require -§- rope, and -J- on 45" slope.
When the slope cannot be self-acting, " engine-planes" arc
used. A stationar)- engine is located at the head, and has a
1 66
MANUAL OF MINING.
'^^v>
UNDERGROUND TRAFFIC. 167
drum which may freely turn and pay out the rope for the
descending cars, and be geared to pull them up returning on the
same or a parallel track. On single-track planes the engine is
non-reversing. On a grade of 1.7 per 100, gravit)' will take
the loaded cars down with a reasonable velocity (empties on a
2.25 grade) and pull the rope after them.. On a 10 per cent
grade a break will be necessary.
The cars usually travel in trains, of 10 to 30 in number, in
charge of a conductor who operates a dead-fall timber-block to
hold the train while the cars are being shunted. So the system
is well adapted for delivery from side-entries at different levels,
and may be used on slight curves by curving the rope on iron
guide-wheels. Ordinarily the rope will last four years. A
14 X 30 cylinder, 3-ton fly-wheel, Jg- steel rope, on a plane
4600 feet long by 80 high, has a daily output of 950 tons of
mineral in 25- to 30-car trains.
31- Of rope-ways there are two classes, the tail-rope and
the endless cable. Each system has its advocates: both are
extensively u::ed in beds, the former for a limiting gradient of
3 in 100, either with or against the loaded cars.
In the tail-rope system, haulage is effected by a stationary
engine, two ropes on drums which are thrown alternately in
and out of gear. The main rope, having a length equal to that
of the road, is hitched to the front end of a train, the tail-rope,
of double this length, passes from its drum around the sheave
at the bottom, and thence to the rear end of the cars ; a short
chain at each end of the train couples the cars to the two
ropes. In operating, the main-rope drum is thrown into gear,
the other out of gear, engine started, and the loaded cars are
drawn from the mine to the outlet, dragging the tail-rope after
them. Then the main-drum is released and the tail-drum
eiigiiged, the empty replace the full cars and return, pulling
the main-rope off its drum. See Fig. 70.
The lower sheave is a clip-clutch. The main-rope is rarely
over \ inch diameter. It is generally replaced ever)' year by a
new one, doing two years of additional service as a tail-rope,
after which it is discarded.
i68
MANUAL OF MINING.
UNDERGJWUND TRAFFIC. 1 69
The length of haul is limited only by the engine-power and
the resistances. While the dip may be anything less than 3 in
100, yet its greatest advantage is manifest on a level or very
slightly falling dip. The velocity of haul may reach as hi'Th
as 10 miles an hour. Each trip takes a train of 10 to 100 cars
accompanied by a conductor, whose duty it is to look out for
accidents, the train being hard to control wlicn the tail-rope
loses its hold. The system is preferred in American collieries,
and is the best plan by which branch-ways may be operated.
Each branch has its own rope passing over sheaves at the ends,
the principal ropes are opened at the proper points for connec-
tion with the branch ropes, the train engaged and hauled to
the end of its journey.
This is an inexpensive plant to build and repair ; it does not
require a double track, though it demands a double length of
rope. With a single roadwa}- the sheave is vertical, and the
tail-rope moves along the roof to its drum vertically above the
other. In this form it is encountered in iron mines. In exten-
sive workings it has dispensed with animal power, and is
advantageously used for slight grades, and even for undulating
roadways. An 18 X 30 cylinder, with 75 lbs. pressure, on a
2800-foot slope, grade I in 200, 4.',-foot drums, \ main- and \ tail-
rope, 30 trips of 17 cars each are made with a velocit}' of 8 to
1 1 ft. per second.
For passing around curves, 24-inch whc._ls arc laid horizon-
tally and be)-ond the inside rails. These carr)- the rope till the
car reaches the turn. On reverse curves they are laid nearer
the inside rail and slightly inclined to the horizontal toward
the centre.
32. The endless-cable systems are much in vogue, and re-
quire less rope than the above-mentioned plan. They are very
suitable for a double-track line of communication with frequent
stoppages and no branches. A continuous motion in one
direction is imparted to the rope by a single wheel or drum.
and the tension produced by artificial means — a friction-grip
or clip-wheel, or else several turns of the rope on the drum
The clip-wheel keeps the chain or rope tight, being on <
a car
170 MANUAL OF MINING.
riage frame, to the far end of which a rope is attached. This
rope passes over a pulley suspending a weight, which main-
tains the tension desired in the tram-rope. On a single track
a reversing engine works the rope alternately forward and
backward, the return-rope being supported overhead or at one
side of the gangway. The power is transmitted by a rope or
chain suspended above, resting on top or supported below
the cars ;
1. In the cheapest, most universal, and effective method,
the chain rests in forks riveted on top of the cars, which are
singly attached at intervals of 25 to lOO ft.
2. For heav)' grades, with intermediate stations the chain
runs on rollers underneath the cars, a short length of chain
being used for connection.
3. For a uniform grade and sharp curves the cars are at-
tached by chain to an endless rope above them.
4. For varying grades and curves without branches, the
cars are singly operated as on surface cable roads.
(i) This system supplies a continuous power which may be
taken off at an\' point. The cars, readily connected and dis-
connected, are distributed singly along the line, from 20 to 100
feet apart, and as the velocity does not exceed 3 or 4 miles an
hour, the boys have ample time to hitch them on the rope.
The capacity is independent of the length, being determined
only by the number of cars delivered. The power engines
have heavy ffy-wheels for regularity and compactness. A
sprocket-wheel keeps the desired tension and prevents slipping.
It is a driving-wheel of 3 feet or more diameter, carrying forks
set radially, and capable of being screwed out and in ; these
are turned a little to seize the chain as it lengthens and drags,
until they are paid out to the limit, when a few links are re-
moved and the forks adjusted. Extensions are easily made
when required ; this is not possible with tail-rope.
This system costs less for power than tail-rope, and admits
of sharper curves and steeper grades, but requires two lines of
rails.
As an example of a plant ; a 5773-foot road with 70° curves, cars (0.5 ton
each) 50 feet apart, at 2.8 miles per hour, delivers 1250 tons per shift The
UNDERGROUND TRAFFIC.
171
chain shows a tension of 4000 lbs. The engine is 17 horse-power, has a drum
of 5 feet diameter, lagged with wood, lasting a year (costs $25); the sprocket
($80) wears out in four months.
A " tail-rope committee" of the North of England Institute
of Engineers reported (vol. xvii. of its Transactions) that, " as
far as the cost of maintenance and working expenses are con-
cerned, this endless-chain system can be applied, with few
exceptions, to every condition of wagon-way with greater
economy than any of the other systems." It is not restricted
by grade, nor by any irregularities or crookedness in the road-
ways.
(2) The friction, and of course the wear, is much greater
than in (ij.
(3) The mechanism of the endless-rope system differs little
from that of (i) except in the method of connection. The cars
at intervals are hooked to the short chains pendent from the
rope, or a small chain is wrapped twice around the rope or into
loops along it. The speed is lower and the cost is higher than
in (I). The first cost of one of 900 tons capacity, 3200 ft. long,
is $4000, and its yearly repairs amount to $200.
(4) Each car is connected b)' a hand-clamp, somewhat like
that in use on the surface cable-roads, similar in action to a
pipe-tongs, and is also provided \\'ith a device to keep tlie rope
on the rollers. Tlie clamp is detachable. At each station
or branch a man l 71/. Jour.: Electric Haulage Plant, Berwind-White Collieries,
T. W. Sprague, LIX. 508; Large Electric Locomotive, LVL 59 and
476; Electric Locomotives for Mines, LIX, 33; Compressed-air Loco-
motive for Mines, LX. 127.
Fed. Ins/. M . E.: Endless Rope Haulage at Tliorncliffe, Rockingham
and Tankersley Collieries, W. Hoole Chambers, III.; An Underground
System of Haulage, John Nevin, III. ; Electric Haulage at the Cannock
and Rugeley Collieries, R. S. Williamson, III.
Amer. Inst. Rl. E: Wire-rope Haulage and its Application to
Mining, Frank C. Roberts, XVI. 213; Electricity and Haulage, Francis
A. Pocock, XVIII. 412; Note on the Friction of Mine-car Wheels,
R. Van A. Norris, XVIII. 508; Electric Locomotives in German Mines,
Karl Eilers, XX. 356.
CHAPTER IX.
SURFACE TRANSPORTATION.
33. The pioneer burro : aerial tramways ; description of the Bleichert,
Haliidie, and Huson types ; capacity, cost, etc. ; regulation of the
tension of the rope. 34. Wire-rope transmission of power; pulleys,
sheaves, rope, etc. ; formulae.
33- Mining in the mountainous regions encounters diffical-
ties in the transportation of the product and suppHes, wliich
are not readily overcome. Often a mine is inaccessible to
wagons, and burros constitute the only means of transportation.
The ore is carefully sorted, sewed up into sacks containing 90
lbs. each, and packed, one on each side of tlie jack, to market.
They travel in trains of 20 to each driver, averaging about a
mile an hour, and return at the same pace with the supplies
for the mine. The cost of filling and sewing the sacks and
their repair is high ; and as it takes 11 jacks to "pack" a ton
away and fetch enougli fuel to run a 26 !iorse-po\\ cr engine 24
hours, it may readily be understood why the much-abused,
patient brutes remain only in isolated camps as companions to
tlie pioneer prospector, for whom they continue to do service
between mine and wagon or mill.
For larger output they are replaced by an aerial tramway,
which is a sort of an endless rope-way that can be run night or
day in all seasons, without road or expensive machinery, and
furnish a cheap, convenient conveyance for ore and supplies,
down a declivity, around bluffs, over intervening hills, and around
flat curves for a mile or more. When the grade to the point
of delivery is about 14 in 100, the tramway is self-acting, the
speed being regulated by a brake ; below this, auxiliary power
is applied to the rope at the upper end.
175
176
MANUAL OF MINING.
There are two varieties, one represented by the Bleichert,
and the other by the HaUidie and the Huson patents. In the
former, one or two ropes are stretched tightly and supported
by standards, 10 or more feet high, to give a continuous slope
from the mine to the discharging point, where they are well
anchored by screw-rods and buckles. The cables constitute
the roadway for the trolleys, from which the tubs are sus-
pended. The trolleys are operated by a single or an endless
rope which passes around clutch-sheaves at the top and bottom.
The tubs carry as much as a ton, and dump automatically into
a bin or wagon. The cost of this system is quite high, but it
can handle looo tons per day. The carrying cable (Fig. 71)
TRAMWAY CAR FOR THE TRANSPORTAriON OF COAL. ORES. SANDS, ic.
SHOWING LUG COUPLING
Fig.
is stationary and about i\ inch diameter, though it is locally
strengthened according to the strain to be carried. A line of
steel rods may replace it for short spans and light loads, but
cable is better, as tending to convert the otherwise transverse
strains into tension.
In a somewhat different style of aerial tramway, one or two
ropes stretch the entire length to constitute the guides for one
or two large skips holding a ton or so, and attached at the end
S URFA CE TJJA NSPOK TA TIOiV.
177
of a rope. They are operated like the gravity planes, p. 165,
and may be self-acting or not. See Fig. 72.
In the Hallidie or Huson designs, a single endless wire
rope. Fig. 7^:,, is supported at intervals of 150 to 300
feet, on suitable sheaves, which are mounted vertically on the
ends of cross-arms fixed to the necessary posts or frames, and
at sufificient height to clear all surface obstructions. At both
ends of the line the rope passes around clip-pulleys set hori-
zontally. The upper wheel is placed on a frame below the
level of the tunnel or shaft mouth (Fig. 72). At the lower end
may be a plain or a grip wheel on a carriage tower frame, which
assumes a position such that a constant tension may be main-
178
MANUAL OF AUKINO
£ ^ Jlfr^fS^^
or ^'
*;^'
^'
S URFA CE TKA A'SPO/! TA 7 'ION.
179
tained in the rope. Precaution should be taken to provide a
hold-down rail on top of the wheels to prevent the carriage
from tipping. The distinguishing feature is that the load is
at once supported and moved by the same rope, which has a
continuous motion in one direction, at a velocity of about 200
feet per minute. With a velocity greater than this on a steep
grade, the loaded rope frequently flies off the sheaves.
Buckets of various designs, according to the character of
the material to be handled, are suspended by hangers or clips,
which are either inserted into the rope or clinched around the
outside of it, and attached at intervals determined by the
amount of material to be delivered. Usually they are wrought-
iron rectangular buckets holding about lOO lbs. each (Fig. 74).
&^
rigj
ff^
nP
ff^^
Nl?
wm }— H)
For the transport of very large outputs the buckets may be
nearer together than the average 200 feet, or larger, and the
rope may be heavier than the ordinary size of f . The buckets
may be loaded at any point along the line, automatically or
by hand, and are unloaded at the lower end by some automatic
device. The carrier strikes a lever, which opens a catch (hold-
ing the bottom in place), and discharges the ore ; a counterpoise
on the bottom closes it again. The hangers are so made that
they may pass uninterruptedly over the rims of the supporting
sheaves and around the terminal pulleys, their consumption is
large, and amounts to $100 per year on a medium line.
The strongest form of intermediate supports are stout
l8o MANUAL OF MINING.
rectangular frame standards of four sills, fiom each end of which
is built an X transversely, from on top of which are heavily-
bolted cross-arms. As these X's lean towards each other at
the top, they are not liable to get out of line, nor does the
weighted side of the rope pull the cross-arm out of level. To
the ends of the cross-arms are boxed the carrying-sheaves,
rubber-lined and loose on the axle. To round a curve, the
standards are nearer together, and the rope is slightly deflected
with each wheel.
A rope-wa)' running 200 feet per minute, carrying 100 lbs.
per bucket every 100 feet, will deliver 60 tons per shift. With
a descent sufficient for gravity to supph' the power, three men
can manage all of its operations. It requires some supervision,
and delivers ore at 20 to 35 cents per ton-mile (inclusive of all
allowances), and about 60 cents per cord-mile for wood. The
line can be completed for $1.30 per foot, and $2000 for the
machinery at the terminals. Curves and long stretches increase
the cost ; grade does not.
34-. For power transference from, instead of ore transpor-
tation to, remote points, a similar arrangement is widel}- applied,
efficient and cheap. For moderate distances, up to a mile, its
efficiency is greater than by an)- other system ; at half a mile it is
90 per cent. The inevitable concomitants — which accumulate
so rapidly that for distances of over a mile electricit}' gives much
better results — are the losses of energ)' due to friction of bear-
ings, air-resistances from centrifugal action, stiffness of ropes,
and elasticity, due to the spiral winding.
fite rope is of the seven-wire pattern, of from f to -^ diam-
^vcS, passing around sheaves, and supported over the intcrx-en-
ing spaces by wheels. The size of the rope increases with the
tension, and that, in turn, depends on the sag allowed, which
fixes the distance bet«'een the stations (60 to 300 feef). Tlie
rope runs in cushioned-grooves on leather or rubber without
slip, noise, or swaying, if the wheels are well-balanced and care-
fully aligned. Those on the driving-side are nearl}' of the same
size as the sheaves, those on the slack-side one half smaller, the
tension being less there. Where it can be arranged, the upper
SUMI'yiCi: TKAASPORTATWN. , l8l
side should be the slack side, and the lower, the pulling side.
Large wheels are advised also, because they keep the two ropes
apart.
Evidently, the power that can be transmitted depends upon
the adhesion of the rope to its driving and driven sheavc-
Grip-pulleys, or clutches, increase this adhesion, and through '
the velocity limit. The product of the velocity and the forc^
at the sheave-rim measures the work done. The force available
at the sheave is the assumed maximum tension, T, less the loss
due to centrifugal force. Not all of it can be used, because
some of it is absorbed in giving adhesion, and this is an un-
certain quantit)-.
Let V = velocity in feet per second;
i/ = diameter of the rope in inches;
za = weight on the journal;
IV = weight of rope between stations;
J = loss, in ft. -lbs., due to journal-friction,
/'' = " " " " " centrifugal force ;
j'V = the horse-power transmitted;
n = number of revolutions of the wheel per minute.
Then J^ = i.^/f'z'^;
j= for each end-sheave, 24g.V-|- o. 185;;';';
j = for intermediate stations, o. 1850(11' -(- \l' )v\
N = i.-fd^'ii, when the diameter of the wheel is 165 times that of i \
and N — '})d''ii, when it exceeds 20uti'.
These latter are approximate values. Six- or seven-foot wheels, with 4"
rope, at 80 to 140 revolutions per minute, will transmit 10.7 to 29.6 horse-
power, while ten- to eleven-foot wheels, with |- to |--J- rope, give 58 to 135 horse-
power.
Tension is adjusted and maintained, as in aerial trams, by
tightening-sheaves on carriages ; for the rope cannot be so nicely
spliced as to get the proper sag, which for spans of 150 to 250
feet should be from 1.3 feet to ^.6 feet when the rope is at rest.
Every two or three months the stretch of the rope is taken up
by shortening and resplicing. With inclined lines the proper
deflections cannot be obtained without tighteners.
Often, instead of a continuous line and an endless rope, a
series of closed ropes and double pu!le)'s in sections do fair ser-
vice, are easily repaired or renewed, and less influenced by
changes of temperature.
182 MANUAL OF MINING.
The following list of memoirs will give aid to a further
investigation of the subject matter of the chapter:
The Eng. Soc. of W. Pa.: Gravity Plane. XII., No. 9, 235.
Trans. AI. iS~ 71/. Eng.: Engine Planes at Wearraouth Colliery^
W. R. Bell, XLV. 219.
Min. &^ Scien. Press : Aerial Tramways, C. T. Finlayson, at Sandor,
B. C, June 1S97, 544.
Coll. Guard.: Various Types of Aerial Ropeways, W. Carnngton,
Mar. 1897, 556.
Atner. Inst. M. E.: Aerial Wire Ropeways, J. Pohlig, XIX. "jdo.
E.&^ M.Jour.: Wire-rope Tramway, English Mt. Mine, Cal., LIX.
55, Vulcan Ropeway, San Andreas, Mexico, LVI. 615; Bleichert Wire
Tramways, LVI. 394, Wire-rope Tramways, Prof. Thiery, LVI. 366;
Brewer's Aerial Tramway, LXI. 230; Wire-rope Tramways, LXI. 208;
Wire Tramway in the Alps, LVII. 124.
CHAPTER X.
PUMPING.
35. Exclusion of water by cribbing and tubbing shafts; building dani,_
and plastering cross-courses in levels ; the use of advance bore-holes
in approaching abandoned workings ; drainage by tunnels; co-oper-
ative drainage; hydraulic rams and the Hungarian system of pump-
ing; bailing by self-filling buckets, skips, and tanks. 36. Single-acting
lift-pumps; details of sizes, of rods, pipes, valves, gaskets, etc. ; spiral
weld vs. ri\eted pipes; formula; for calculating the dimensions of
parts; cost of surface plant; descriptions of the Cook, Wormer.
and Bull pumps; working by steam or water pressure; formulae.
37. Single-acting force-pumps ; method of altering lift- to force-pump;
description of the mechanism and operation of the Cornish pump ;
size of pipe, length of lifts, and dimensions of pump-rods; tapering
rods, catches, V-bobs, and balance-bobs; formulse for the thickness
of pipes, discharge, etc. ; account oi the Ontario, Friedensville. and
other mammoth plants. 3S. Regulation of the speed of pumping;
churning of the plunger, vibration of the rod, and its prevention.
39. Double-acting pumps, sinking pump-^, Cushier system ; steam-
pumps; their construction and operation; formula; for sizes of
cylinders, discharge, etc. 40. Comparison with the Cornish pump;
relative advantages of the steam plants; pumping-engines ; com-
pound and cfjndensiug pumps, duty and calculation of; rotary
pumps ; water- pressure engines ; Calif(irnia and Nevada systems ;
electric [lumps: the windmill for power.
35. TURXIXC; to the subject of raising water from the mines,
we must not forget that water gain.s its entrance by many and
untraceable ways. In some workings it flows incessantly
from some watery stratum, in others the seepage is interm.it-
tent. The subterranean current is easily excluded from the
mine by the use of a cement lining, or an iron tubing to the
shaft (see II, 63j, but the seepage accumulates and must be
pumped off, unless the workings possess a natural drainage or
an easy effluence by adit or tunnel for the upper ground. A
gutter at the side of the track, or under the tramway path,
with a slope of I in 500, readily carries off the water, and not
1S3
1 84 MANUAL OF MINING.
uncommonly delivers it to a small wheel to drive a ventilating,
fan. Generally the seepage, following the hydrodynamic law,
increases with the depth of the opening, and a very liberal
sump is provided for its accumulation. Often one shaft and
its workings become, naturally, a sump for the entire district,
and drain all the neighboring properties above its level, and this
suggests a simple means of keeping one's mine dry. Other-
wise, as the amount of water to be encountered is uncertain,
provision must be made for the handling of a large volume,
according to the history of similar properties. In some coal-
mines of Pennsylvania as much as 4000 gallons of water are
raised per ton of coal ; in Colorado often 40 tons of water per
ton of ore. The Ontario and Friedensville mines raise man}'
times larger volumes. The magnitude of such work demands
the employment of powerful machinery, and often on a plan
too elaborate for the means of the average operator. In some
localities the drainage of the district is accomplished b}' a co-
operative scheme with extremely beneficial results. A long
tunnel penetrating the country at a level much below the
lowest point of exploration drains considerable territory, dis-
pensing with the heavy individual plants, and extends the ex-
ploration and the productiveness of the mines. Numerous
examples of tunnels ten miles or more in length maybe quoted,
some even carrying so much water as to become canals for
transportation. Several such drainage tunnels are driven in
the coal regions of Penns}dvania.
Upon cutting a wet cross-course to the vein, it is a common
practise to plaster it up : or, in encountering old workings, to
build a brick or stone bulkhead, arched convex towards the
water (Tig. 197)- To provide means for the escape of the
accumulated water which might otherwise do injury, a cast-
iron pipe is built into the dam near its top, and another near
the bottom. Either, or both, may be plugged as required.
Similarl)-, in approaching abandoned works, it is required by
law in some States that a bore-hole be kept 30 to 50 feet in
advance of the drift, and flank-holes on each side, to guard
against dangers from the sudden breaking into the reservoir.
PUMPING,
i5
Dnder certain conditions, in stratiiied regions, a hole is
drilled from tlie sump down to some permeable stratum, into
whicii the water is discliarged.
When the surroundings are such that a tunnel may not be
jjsed for the unwatering of the mine, pumping arrangements
are indispensable. The earlier forms were crude, the engine
being of recent date. Surface water-falls were employed to
operate wheels, which raised bucketfuls from below ; or, the
surface water was arranged to compress air in a reservoir at the
surface, from which pipes to the sump conve}^ed the com-
pressed air, the elastic force of which, in turn, forced the water
up to the surface through another pipe. This is a wasteful
system and intermittent, but doubtless was cheaper than any
other means then available.
At the Comstock mines a sort of hydraulic ram is used, by
which iSoo gallons are pumped from the
2600-foot level to the Sutro tunnel at 1600
feet. The air-pressure in the accumula-
tor is 960 pounds per square inch, and the
pipes at the bottom sustain a pressure of
2000 pounds. The engine-pressure is 80
pounds, and the actual duty given, 35 horse-
power per ton of coal. This has just been
introduced at Eureka.
The efficiency of the ram diminishes
with the ratio between the quantity of
water raised and that used. With a fall
of I and a lift of 4, the efficiency is 86
per cent; if the lift is ten times the fall,
it is 53 per cent ; at i to 20, it is 17 per
cent ; and with I to 26, it is o.
Small volumes of water are handled by
buckets, obtainable of any size, and with a
capacity up to 200 gallons (Fig. 75). At the
bottom is an inlet valve by which the tub
is quickly filled as it sinks into the sump ;
it is then hauled up, its valve closes, and at the surface it is
1 86
MANUAL OF MINING.
discharged by being brought down on a pin which again opens
the valve. Li some mines the water-bucket is attaclied under-
neath the cage, and travels continuall}? with it. Bailing-tanks
(Figs. 76 and "jj) holding 450 to 900 gallons, with balanced
i
a
D
I
D
Fig. 76.
Fig. 77.
compartment of the shaft, and manipulated by an indi\'id
ual drum, give great satisfaction in many properties. Slopes
are equipped \\\\\\ a similarly valved skip, the emptj'ing
being done from the mouth, as with ore. But if the mine
makes more water than can be handled b}- these means at
PUMPING.
187
-t
7«
1
i%
spare hoisting moments, special machinery is added, and of
one of two kinds : the single-acting lift-pump, or the force-pump,
single- or double-acting.
36. Pumps of the first class are much in favor because of
their simplicity. Their use is restricted to
vertical shafts and a lift of less than 300 feet.
A plunger-rod terminates in a piston in the
bottom length of a pipe, where it "sucks" up
from the sump water which, with the next up-
stroke, is lifted into a stand-pipe, from which
it is ultimately discharged at the surface.
The stand-pipe, of a diameter commonly 10
inches, often as much as 20, extends from
bottom to top. It is of cast-iron, lap-weld,
wrought-iron, spiral riveted seam, or weld-steel,
procurable in lengths of 5 to 20 feet. The cast-
iron pipe, having a smooth interior and uniform
diameter throughout, is preferable and more
convenient than the riveted pipe (Fig. 78) or
the lap-weld iron (hig. 79j , but as it represents
too much dead-weight for the strength, its
days of utility are nearing an end. The ideal
pipe is of steel, which gives the lightest,
strongest, and most durable tubing; this may
be had in four grades, light to extra heavy.
It is made of spirally-laid sheet steel riveted
at the overlapping-joints or cold-hammer
welded. The pijies are united by bolting
together ai: tlvj flanges, which are riveted,
screwed, or locked on the [npe (h'ig. 79); or,
preferably, they are coupled on the hub-and-
spigot plan of sleeve (i^ig. 80). This is a
double socket, into which the pipe is slipped,
" oakumed," and leaded from each side, as shown. For
joint the pipes have expanded ends.
A water-tight joint is secured by placing rubber, leather,
lead, or, best of all, corrugated copper gaskets between the
this
1 88
MANUAL OF MINING.
flanges, which are then bolted together while lowering.
Spcnce's metal, used as a calker, oilers an excellent joint, is
cheaper than lead, and ought to be better known.
The pipes last fifteen or twenty years unless the water is
Fig. 79>
corrosive, in which case gun-metal is used. If the water is very
bad, wooden pipes are made b}' hollowing the trees, fitting the
joints, tarring them, and strengthening by wrought-iron bands
at every three to six feet. In many mines recourse has been
had to these as the only stand-pipe that will last over six weeks.
Fic. 80.
At the lower end of the stand-pipe a 12-foot length of cast-
iron constitutes the working-barrel, in which oscillates a piston
carrying an upward-opening valve, similar to that at the lower
end of the barrel (Figs. 81 and 85). For acidulous waters the
barrel is bushed with gun-metal. It should be thick, to admit
of being bored out several times, as it is rapidly cut away by
the gritty waters during sinking.
The valves are made of several thicknesses of oak-tanned
leather cut into discs, tacked together, and slipping easil)- on
a grid at the top of a cast-iron cellular ring-bucket. A per-
forated cast-iron guard on the grid limits the rising of the valve
as the water passes through the bucket. These lifting-clacks
are raised clear of their seats by the rising water, and open as
FUiMPJNG.
I 89
Fig. 81.
CHICflGD IROrt' WORKS
»;. :j.
190 MANUAL OF MINING.
widely and shut as quickly as possible. The cellular-ring
bucket casting is all there is of the piston, which fits fairly well
in the barrel, and has no other packing than that offered by the
leather discs forming the valve, and which are cut larger than
the cylinder. The rapid movement, the wear, particularly dur-
ing sinking, and the heavy pressure upon these valves, consume
A set once every two weeks, or oftener. Substitutes have been
suggested, amongst them flexible brass or gutta-percha plates,
but they have not proven good, nor have the brass balls or
conical poppets had any marked success. The valves are re-
paired or replaced by raising the entire pump-rod, opening the
standpipe or opening a bolted door-plate in the barrel opposite
the valves (Fig. 81).
Below the barrel is a length of pipe or flexible hose dipping
into the sump and receiving the water through a perforated
strainer. During sinking this suction-pipe must follow the
lowering of the sump, and while blasting it is raised for each
shot or boarded over. The flexible hose is preferable, because
it can be bent and adjusted to lie on the bottom of the shaft,
or hang vertically in the sump. It is of wire-wound rubber and
canvas hose, which will endure considerable hard usage, and
cost, for a 14-ft. length of 10 inches diameter, $65. Without
this the only way to keep up with the sinking is to use a tele-
scopic joint on the working-barrel, allowing for say 10 feet
play (Figs. 82 and 85). When the water-level has receded be-
yond the mouth of the suction-pipe, a length is added to the
stand-pipe at the surface. The working-barrel can never be
more than 28 feet from the sump-level ; in mountainous districts
still less ; at 5600 feet altitude, 23 feet ; and at 10,000 feet, 18
feet. Usually the working-barrel and suction-pipe are sus-
pended by chains from two stulls resting in the cribbing, and
the stand-pipe supported at intervals by stout reachers.
The piston, or " bucket," is attached by an iron fork (Fio-.
84) to a wooden rod 4 or 5 inches square, extending up through
the pipe to the surface where it is connected either with one end
of a walking-beam or to the piston of a single-acting engine.
As it receives a tensile strain, the joints are scarfed and strapped,
PUMPING.
191
or, if the ends are flushed, two continuous lines of strap-iron
breaking-joints are bolted together through the rod. The
latter plan reduces the breakage and the number of stoppages
for repairs. (Drill the bolt-holes in the iron ; never punch them ;
and keep a good set of taps, dies, and drills for this work, also
H good iron crab or winch.) A 4 -inch rod is large
-iiough for a i2-inch pipe; and a 5-inch, properly
spliced and strapped, for a 13-inch to 16-inch delivery.
The size of the straps is easily calculated. The area
of each one, a, should be d'^D ~ 40,000. A 200-foot
pump-rod requires two straps 4 X -} or 3 X i for a
lO-inch pipe.
At the surface the column-pipe terminates in an
elbow discharge or in a laundry-box and trough, the
pump-rod continuing up to the framing. The mechan-
ism by which the motion is communicated to it is
simple. A stout frame, with two samson posts, sup-
ports a working-beam receiving its oscillatory motion
from a pitman actuated by a crank-arm, adju,stable to
a I-, 2-, or 3-feet radius, giving strokes of double this
length, at the opposite end, to the pump-rod, which
requires little force besides its own weight. The arm
is on a shaft turned from the engine by cog, geared i to
6 or 7, giving 12 to 20 strokes per minute to the rod.
The iron-work of this frame, inclusive of cogs, pulley,
and castings, will cost about $250. The wood-work,
including a 24-ft. x 15 inches square walking-beam,
about $125. Whereever cog-gearing is required for
heavy work, the author insists upon a solid hub if the
wheel is not too large for a single casting.
To save the cost of this cumbrous framework and
'.he loss of power, a steam-cylinder is placed over the
shaft, standing vertically, its piston being bolted to a fork
on the rod. This arrangement requires no framing beyond a
solid foundation for the engine, and involves the purchase
merely of a steam-cylinder. The piston receives steam on
both sides, though, theoretically, it need only be single-acting.
I''IG. 34.
■^
MANUAL OF MINING.
Illiir
It is not certain that this form gives a
higher duty per bushel of coal than
the drive-rod pump, for, while the fric-
tion is less, the steam consumed in
the down-stroke is unnecessary, ex-
cept for increasing the speed. The
main objection preventing its more
-jeneral adoption is the large portion
jf the shaft-mouth it covers. Be-
;ides, to lengthen or repair the rod
)r column-pipe, the cylinder must be
displaced, or the additions are made
below ; either is slow. This pump
cannot be used in slopes ; the irregular
wear of the cylinder on one side can-
not be compensated for, nor the fric-
tion of the rod in the pipe counter-
acted. These cylinders are easily set,
not very expensive, and work to a
charm. A 12x36 cylinder, with fit-
tings, cost $325 ; larger ones may also
be had at moderate prices. They are
known as the " Cook " (Fig. 86), or the
" Wormer " pump, from the name of
the manufacturers. B}' the name of
" Bull " pump, first introduced by Wm.
Bull in 1798, they are better known
in collieries, where their size is greater
than, and their piston-speed about
the same as, the former varieties,
which run best at 24 double strokes
of 3 feet each, wliile the latter makes
6 or 8 of 10 feet each, in a cylinder as
large even as 55 inches.
Where water under considerable
head is obtainable at the surface, its
property of incompressibility may be
utilized by admitting it under the
piston to raise it, after which it flows
PUMPING.
193
out. Unless kept well under control, it causes shocks and
blows. A pressure of 57 pounds was obtained in a 50X 120"
cylinder from a liead of 132 feet, and 5000 gallons raised per
minute 132 feet, by a 42" plunger.
On the down stroke the rod falls through the column of
Fig. 86.
water, while the valve in its piston opens and the clack of the
working barrel closes. Returning, the valve's action is reversed,
water rises from the sump into the working barrel, and all that
above the piston is lifted a distance equal to the stroke, and a
column of water simultaneously discharged at the surface.
If d be the internal diameter of the pipe in inches, and L the strol(:t. 1895, 779; Fire-damp Periodicity, A. Doiieu.\,
Jan. 1896, 65; Composition of Fire-damp, T. H. .Schlossins.;, Jr., Dec.
1896, 1 170 ; Causes of Sudden Outbursts of Fire-damp, H. de la Goupil
Here, 856, July 1897, 61 ; Composition, Study of, T. H. Schloessing ct tils.
May 1897,999; Air in Coal Mine, Prof. Clowes, Jan. 1896, 222; Some
Efifects produced by the Sudden Compression of the Ventilating Air-
234 MANUAL OF MINING.
current in Mines, James Ashwortli, Nov. 1S95, 974; Dangerous Gases
of tlie Coal Mine, Prof. F. Clowes, Jan. 1897, 16.
Coll. Mgr.: Extinctive Atmosphere Produced by Flames, F. Clowes,
No. 124, April 1895; Fire-damp Accumulations, Mar. 1893, 58; Fire-
damp Analysis, Aug. 1893, 158 ; Detection of Gas in Mines, May 1893, 91.
Ann. Des Mines: Sur le travaux de la Commission Prussienne du
grisou, MM. Mallard et le Chatelier (8« Seriej IX. 638; Sur les precedes
propre a deceler la presence du grisou dans I'atniosphere des Mines,
MM. Mallard et le Chatelier (7« Serie) XIX. 186.
Fed. Inst. M. E.: The Detection of Fire-damp, James Ashworth and
Frank Clowes, II.
E. &^ Al.Joiiy.: Detection and Measurement of Fire-damp in Mines,
G. Chesneau, LVI. 213; Respirability of Air in which a Candle-flame
is Extinguished, Frank Clowes, LXI. 515.
///. Mi7i. Inst.: Stone-damp, White-damp, Peter Jeffrey, III. 50;
Fire-damp in Illinois Mines, J. Rollo, I. 106.
Trans. M. ^ M. Eng.: Experimental Apparatus, Sampling Fire-
damp, M. Coquillon, XLV. part 5, 106; Indicators of Fire-damp, M. E.
Hardy, XLV. part 5, 107 ; Testing Upcast Currents, Anon., XLV. part
3, 28.'
Coll. Eng.: Barometer and Exudation of Gases, editorial, Dec. 1896,
196; Composition of After-damp, T. H. Schlossing, Jr., Dec. 1896, 211 ;
Experimental Apparatus with Fire-damp, H. Schmerber. April 1896,
205; Lamps, "Easy lessons," July 1896, 285; Physiological Action of
Black-damp, editorial, May 1895, 228; The Composition, Occurrence,
and Properties of Black-damp, editorial. May 1895, 228.
CHAPTER XII,
METHODS OF VENTILATION.
44. Methods of ventilation of a tunnel or advancing gangway; by con-
duit or brattice; single- and double-entry, and outlet; diagonal, or
adjacent, systems for double-entry; increase of temperature with
depth; limit of the depth of minmg; natural method of ventilation
by two outlets at different levels ; limitations of the method by season
and depth; ventilation of railroad tunnels; account of the different
experiments and that finally adopted. 45. The flow of air by changes
of pressure or of temperature ; the flow of any fluid under a change
of tension ; motive C(Mumn ; forinulse. 46. Methods of accelerating
natural ventilation, etc. ; furnace ventilation ; cost and construction
of the furnace; temperature and volume of the air produced ; dangers
and limitations in its employment; dumb channels in lierv mines;
exhaust-steam as a ventilator. 47. Mechanical ventilators ; descrip-
tion of hand-fans and their adaptability , blowers; Root fans; cham-
pion blowers; use of compressed air as ventilator; exhaust-fans;
details in the construction, arrangement, efficiency, and cost of the
same; Guibal fans; lines of improvement; method of housing;
outlets and connection ; description of the Waddle, Schiele, Lemielle,
Cooke, and Fabry fans ; comparison of ihem ; effect of a low
barometer and high temperature on the volume of the exhaust ; fan
vs. furnace. References. 48. The theory of the action of the fan ;
its equivalent orifice ; its efficiency. 49. Principles of design for fati ;
formula;; example. References.
44. T<.) secure ventilation in the confined workings of a
mine, a conduit must be furnislied by whiclt the warmer and
lighter air may ascend to be supplanted by cold or compressed
air entering by a different compartment; and to maintain a
constant air-current throughout the workings both inlet and
outlet must be afforded for the flow by means of two separate
entries or by partitions in the one shaft. Shafts, in process.
235
236 MANUAL OF MINING.
of sinking, or a mine having but a single entry, may discharge
their vitiated air througli the wooden air-tight box-pipe pro-
vided for the purpose, or, if there is small liability of corro-
sion, through a galvanized iron pipe, the lemainder of the
entry furnishing the inlet. Because of the wide difference in
the areas of the two air-waj^s so provided, the ventilation is
not likely to be good, and it is far better to divide the main
tunnel or shaft or mine working into two compartments of
nearly equal area, one of which will serve as an outgoing
conduit.
From the fact that the current in a single-entry mine is
continually interrupted by the other uses to which the com-
partment is put, and that there is a liability to injury of the
partition, box or pipe, this plan is objectionable when a large
volume of air is required, because the safety of a great number
of men is dependent upon this airway for escape. The wind,
moreover, disturbs the ventilating current; the movement of
cars, cages, and rock or coal in chutes is also irregular in its
influence upon it; and the unusual heat from underground
steam-pipes, engines, etc., sets up counter currents, though
any of the causes mentioned may occasionally have a bene-
ficial effect. Thus a double-entry to the mine becomes not
only precautionary, but also imperative; and as the depth
and extent of workings increase, the insufhciency of a single-
entr)' becomes more and more manifest. Even metalliferous
mines should be provided a double-entry, for the numerous
caves that have occurred, penning in dozens of men without
chance of escape unless the rescuers can reach them before
suffocation ensues, and the fires that frequentl}' cut off the
employees from the outlet and suffocate them before extin-
guishment is effected, are sufficient arguments in favor of
double-entry, even if the necessities for better air do not
appeal to the operators.
The coal-mining ordinances now exact two distinct out-
lets, separated by a safe distance of unbroken rock. The
upcast, advisably, should terminate in a large chimney, high
enough that its draught be not influenced by changes of wind
**'
METHODS OF VENTILATION. 237
or the surrounding buildings. The location of the two
entries, in reference to each other, varies within wide limits.
One plan consists in having them near together, thus concen-
trating the plant. Both air-ways being carried with the
development, the current passes through to the extreme end
of one and return by the other. Then as the work deepens,
each lower lift is connected with the air-ways of the upper
lift, and receives ventilation with its advance. The other
plan is the " diagonal system," the shafts being at the
extremities of the workings. While this is well enough for
long-wall method, the ventilation must meanwhile suffer until
the connection has been made.
Two compartments in a single-entry may be easily
obtained in coal furnishing sufficient rock from the roof or
from partings by driving a wide gallery and walling it up
centrally with the waste; but if there is not rock enough for
tliis, two entries are carried, with the usual pillar between
them, having connecting" throughs " at intervals of less than
100 feet, each being closed as fast as the next one is com-
pleted. To ventilate that part of each entry between the last
connection of the entries and its face, it is subdivided by a
canvas brattice along which the current moves (see 53),
fastened at the near side of the " tlirough " and leading up to
the work; or the faces may be connected by pipes through
the door closing the intake entry without interfering with the
haulage. The practice of relying upon diffusion to do the
work of ventilation is pernicious. These remarks also hold
true regarding the " throughs " connecting the rooms in pillar
and stall working, where diffusion is usually relied upon for
the needful amount of oxygen.
A large number of mines, even some of the coal-mines,
depend for their ventilation solely upon natural means, and
•this may suffice in small mines. But as the workings are e.x-
tended the numerous connections which are necessary for
development or convenience of handling the materials may be
planned to serve also for ventilating ways without additional
cost.
, --.'>
23^5 MANUAL OF iMIMAG.
In planning the direction of gangways and of rooms in
coal-mines, usually the question of haulage is of the first con-
sideration, unless it be that the " cleats " are so pronounced
as to determine the direction of work. At the same time due
attention must be given to the matter of ventilation, that the
requisite amount of air be given each working-room, and that
too many men be not dependent upon the same air-current
circulating through the mine; whenever the mining conditions
require a subdivision of the incoming air-current into small
currents, each being distributed to its own district and group
of men and each separately discharged, it becomes evident that
the ventilation of such gaseous mines must recei^^e special at-
tention, not only as to the direction in which the air-ways are
driven and their cross-sectional dimensions, but also as to the
means of producing the suppl)? of air. In such cases the fresh
air should be carried, if possible, to the deepest point in the
mine, whence an ascending current may be conveyed through
the workings until it is returned to the surface. Especially
is this advisable in steep coal-seams carrying fire-damp.
The ventilation' must be so arranged that as many inde-
pendent ventilation districts as possible be provided with
separate air-currents; and especially must each lift of work-
ings be supplied by the shortest way with the necessary
quantity of fresh air, while within the separate lifts of work-
ings the air-current must always be ascending — except in
cases in which the descending air-currents are not used for
any further ventilation purpose, or when, in certain well-
ventilated working places, great thrust of the measures
renders very difficult the keeping up of special return air-ways.
In metal-mines, where the development is of slower growth,
the rock hard, and a comparatively small force is at work, the
amount of air required is small, eitlier for inhalation or for
the dilution of the gases developed therein; hence a single
shaft with two compartments may suffice, the circulation
being left to natural sources. This, however, will be in-
adequate when the shafts and workings reach a depth of
several hundred feet, in which case other means must be em-
METHODS OF VENTILA 7 lOJV, 239
ployed. The use of compressed air for drills, pumps, etc.,
may supply the deficiency of pure air which natural ventila-
tion may fail to furnish, yet a fan, exhausting the air from
one outlet or forcing the air into the other, seems imperative
with extensive workings.
Below a moderate depth, where atmospheric and surface
changes cease to have influence, there is in the undisturbed
rock an increase in temperature with an increase in depth.
The depth at which the temperature of the ground will be
found to be invariable and equal to the natural temperature
of the locality is about 50 feet below the surface. Beyond
this it is an observed fact that in all artificial openings the
temperature of the rocks increases for at least a moderate
depth, within which the mine operator is concerned, at the rate
of about one degree F. for every 68 feet of depth. This in-
crement is not constant for all localities, nor indeed for the
same mine, but generally it may be said that as we go down
the temperature of the mine increases more or less uniforml)-.
This increased heat is often a great drawback to mining, and
will ultimately limit it apart from the lesser mechanical diffi-
culties. As to what would constitute the limiting depth to
which mining may be prosecuted, it can but be said that at
present several mines, with the exception of the Comstock
and those which are in ore-bearing districts feeling the effects
of solfataric action, are working at over 4000 feet. Regarding
the exceptions stated, it is certain that unless some means be
discovered for rendering their lower levels habitable, the limit
of mining depth is soon reached. It is stated that a 2800-
foot level of the Yellow Jacket Mines has been abandoned
because of the excessive temperature, in many rooms of
which the miner is compelled to return to a cooling station
after laboring only twenty minutes.
An interesting report bearing upon this question of the
rate of increase of temperature with the depth of subterranean
explorations, made by a sub-committee of the Royal Com-
mission on Coal, reaches the following conclusion: That the
limit of depth to which mining is possible depends upon
■*v
240
MANUAL Of MINING.
human endurance of high temperature, and to the extent to
which it would be possible to reduce the temperature of the
air which came in contact with the heated rocks; that there
is no limit caused by considerations of a mechanical nature as
to the size of rope for hoisting-engines, nor by any considera-
tion of the enhanced expenditure for shaft sinking, for haulage,
or for pumping; regarding the latter, the experts testifying
before them demonstrated that water is seldom, if ever, met
with in large quantities at great depths in mines. It there-
fore appeared that this increase in temperature is the only
element needing consideration regarding the limits of pro-
spective sinkings or workings.
A summary of the results of temperature observations
made under the direction of the British Commission Com-
mittee shows the mean increase of temperature per foot to
0.01563, or one degree F. in 64 feet, the extremes being
0.0077 '" '^I's Bootle waterworks bore-holes, and 0.025 i'l the
Carrickfergus shaft. At the Adelbert shaft, Prussia, observa-
tions five times a month, in different levels, for a year could
deduce no regular law of increase; at the 30th level, 3200
feet, the temperature was 98° F.
The " natural ventilation," so-called, depends upon the
foregoing principle, that the relative temperatures of the air
outside and of that inside the mine are such as to give rise to
a change of volume and of tension that will incite a circula-
tion. So that if two openings be made
and connected below, a current will
be established down the lower and
shorter opening in winter, and up the
same during the summer, as the arrows
(Fig. 99) marked S indicate. In win-
ter the direction of the current follows
that of the arrows, W. The amount
of air thus set into circulation by the
changes of the exterior temperature will depend upon the
relative difference of temperature between the mine and sur-
face, and also upon the depths of the shafts. When these
Fig. 99.
METHODS OF VENTILATION. 24 1
differences are slight it is not easy to predict the direction
which the current will take. As for example, in the fall and
spring it will fluctuate from one to the other. When, how-
ever, these differences are great, a current will be set up which
tends to continue in the same direction so long as these
differences remain. Thus in summer the current will follow
(Fig. 99) the arrows S\ in the fall little or no current will be
set up, in the winter the current will reverse and follow the
arrows W; in the spring the conditions are again nearly
balanced, and little current will flow. When the shaft attains
a depth of Soo feet, the subterranean air is always hotter and
lighter than the surface air at any season; and unless the two
outlets have a great difference in elevation, an uninterrupted
current will continue, without fear of reversal, down the lower
and shorter opening.
While this method may be universally practised under
favorable conditions in metal-mines, it is evident that in
collieries one danger arises from the reversal of current, for at
one time the current, following the arrows marked 5, carries
the air through the gangways, whence it is distributed among
the work-rooms, to be returned to the surface by way of the
longer and deeper shaft; but during the other season the
air may follow the arrows marked W, thus entering the work-
ing places first, and departing thence through the gangways,
makes its exit by the lower or shorter shaft. If, now, there
be a number of abandoned rooms or goaves connected with
the working rooms, it is manifest that in the latter season the
air must pass through them first before reaching the men at
work, and thus carry noxious gases with the current to spread
calamity by explosion or fire. Again, the fact that no air AviU
circulate during the vernal seasons would render the provi-
sion for supplementary means of ventilation imperative. Air-
currents which have served for ventilating preparatory work-
ings or prospecting drifts in the virgin seam never should
pass over stalls or working places where men are engaged, on
its way to the air-level.
45. The atmospheric air which surrounds us possesses, in
242 MANUAL OF MINING.
common with all other gases, in consequence of the repulsion
between its molecules, a tendency to expand into a greater
space. This indefinite expansion, by reason of which every
gaseous fluid, not restricted by an extraneous force, continues
to expand to the tenuity of interstellar space, results in the
creation of an air-current whenever by an increase of tem-
perature or a diminution of pressure the given mass of air
expands in opposition to the attraction of the earth and rises
into the upper strata. This upward flow will continue so long
as the gas expands until the resistance encountered by it is
equal to, or greater than, the repulsion among its molecules.
It is this readiness with which gases tend to adjust themselves
to the varying conditions of temperature and pressure that
plays so important a part in mine-ventilation. The tension
of a gas increases with the condensation, and the density of a
given mass of air is proportional to its tension; or, since the
spaces occupied by one and the same mass are inversely pro-
portional to their densities, the volumes 11 and ?/' occupied
by it are inversely proportional to its relative densities p
and /'. The energy stored up by a given quantity of air,
when compressed to a certain degree, may be measured by
the work restored by it in expanding, and this energy may be
converted into motion producing a current, or it may result in
a pressure when that tendency to motion is resisted, or when
the motion is suddenly arrested.
The volumes, u, assumed by a given weight of a gas are inversely as the
corresponding pressures per unit of surface ;
ii : it \\ p' : p.
If the temperatures change while the pressures are constant, the volumes,
reduced to absolute zero (— 461° F.), will be found to vary proportionally.
n : 11 :: 461 +/ : 461 -\- T \
t and /■ being, respectively, for up and ?//', Fahrenheit readings.
The weight of a cubic foot of air at a temperature /, and a barometric pres-
sure B, in inches of mercury, is obtained by the following formula, and at a
temperature T, is IV, expressed as follows :
1-3253^5 ,,r 1-32535
iv = , yv ^^ .
461 + t 461 + r
METHODS OF VENTILATION. 'ZA.l
That portion of the energy stored up in the air which is
expended during its expansion in dynamic effect causes a
" wind " or " draught," the velocity of which depends upon
the difference in tension.
The velocity with which gaseous particles will move,
whether their temperature has been increased or their pres-
sure decreased, is measured by the formula
in which H is the head due to the difference between the
tensions, or densities, of the initial state of the condensed gas
and the final state of the expanded gas. Atmospheric air,
which, normally, is under a barometric pressure of 29.92
inches and a temperature of 32° F., when flowing into a
vacuum attains a velocity, in feet per second, which is
equal to
'~P
V= V2,(rH = 8.0
Y o.ooiiS
The total difference of pressures per square foot is represented
by Pin pounds, and the weight of a cubic foot of tlie warmer
or attenuated gas b_\- W.
So, too, the velocity with which compressed air or steam
escaping freely from a pipe or other reservoir of the same may
be ascertained, the value to be supplied for //, the head to
which the velocity will be due, beuig equal to the pressure in
pounds per square inch under which the gas exists, multiplied
by 144 and divided by the weight in pounds per cubic foot
of the exhausted fluid.
When, however, two masses of air of equal height but of different tensions,
p and p\ are exerting a pressure upon one another through a connecting con-
duit, the resulting difference in pressure per unit of area of base measures the
motive force ; in which case F is the total difference of aerostatic pressure in
pounds per horizontal square foot of sectional area of base, and JV the weight
per cubic foot of the rising column of air.
If, then, a column of air at t° Y ., D feet high, with a base of one square foot,
244 MANUAL OF MINING.
be heated to T" F., its new height would be greater by some quantity which we
may call M. If two such columns be connected, being of the same depth but of
different temperatures t and 7" respectively, the latter column would be lighter
than that at t° by a quantity D(w — IF) ; and so long as this difference in tem-
perature is maintained, this difference of pressure, which we may represent by
/", ensues, by reason of which the hot column of air would be driven upward,
producing a draught with a velocity, F, due to the aerostatic head M. To hold
this force, /", in equilibrium would require a resistance D(w — IV) pounds per
square foot ; or the pressure of an additional column of warm air weighing W
pounds per cubic foot, of a height of 71/ feet,
,,^ni.-..-W)^^^^T-t
IV 461 +/
This quantity M is known as the motive column to which is due the velocity
of the flow of air, and if no resistance is offered to it, motion will take place.
It may be represented by OT (Fig. 99), which equalizes the pressure of the
unequally heated columns of air below the level of the line 00.
When two such shafts are of unequal depth, as at O and
M in Fig. 99, and have equal exterior and interior tempera-
tures, a rarefaction of the air- in either one of them not affect-
ing the other would result in a diminished pressure upon the
bottom, just as is obtained by a difference in temperatures;
a rising current is established therein, with a velocity depend-
P
ent upon the ratio jt>, in which P is the difference in the
weights of the two shaft columns of a base one horizontal
square foot in area and a height D\ and W is the weight of
a cubic foot of the rarefied air.
For the purpose of mine-ventilation there will be required
a motive column much larger than that here obtained, because
of the enormous friction of the air in rubbing along the rougli
surface of the workings, turning sharp corners, and squeezing
through small openings. The resistance due to this cause
amounts often to as much as 90 per cent of the power. In
other words, only one tenth of the theoretical motive column
becomes effective in producing a current, and the actual
velocity of the air-current, v, does not exceed one third of the
theoretical velocity, V. due to the head M.
The principle upon which chimney draughts for boiler or
other heating apparatus depends is also similar to that here-
METHODS OF VENTILATION. 245
'described, excluding, of course, frictional allowance. In
chimneys for boiler-furnace draughts, the fire burns best when
I-Fis 0.5ZC;, and the height of the manometric column in the
chimney is about one half an inch of water.
It is evident, therefore, that the height of a motive column
depends upon the difference in temperatures or a difference
in tensions, or both, of the gaseous mixture contained in the
two shafts or entries to the mine. A measure for this motive
column may be had in feet of head of pressure per square
foot of area of the base, or in the number of inches of a water
column in the manometer which corresponds to this weight.
Insomuch as a column of water one inch high and a square
foot in area of base weighs 5. 184 pounds, the height, ;«, of a
water-gauge column which will balance the pressure P is equal
to P ~ 5.184.
Let M be the head corresponding to the motive column,
V the velocity of flow of the upcast air per second ; then is —
the effective velocity-head of the issuing air; and if W \s the
weight of a cubic foot of the warm or attenuated rising air,
the theoretical energy of the moving air per second is WM,
and the effective or actual energy is W — , or o.oi 5 53 ,'Fi''.
That portion of the energy which is consumed in overcoming
the friction of the mine is therefore W{M — 0.01553?^''). It
is this lost energy which is measured by the water-gauge.
As the mine resistances are reduced, so the water-gauge read-
ing is reduced, and the ef^ciency of the mine increases, per-
mitting a greater actual return from the expenditure of the
same potential force.
The height, ;«, of the water column being measured in
inches, the number of horse-powers, //, necessary to produce
a ventilating current of Q cubic feet per minute is known by
the following formula:
H = 0.000157 1 (?7«.
The indication, therefore, which the water-gauge reading
246 MANUAL OF MINING.
gives of the ventilating force is evident in the above formula
— that foi a given quantity of air, Q, in circulation, the horse-
power necessary to produce ventilation increases with the re-
sistance of the mine.
46. There are several methods by which the natural ven-
tilation may be accelerated and properly distributed to meet
all the requirements of the mine, each of which contemplates
some method either of decreasing the tension of the mine air
to enable the return current to ascend to the surface, or of
increasing its tension by the use of a compressor to force
atmospheric air into the mine. The several means by which
these results are attained may be, first, a furnace built at the
bottom of the outlet shaft, or a fan ; or, second, a blowing,
propelling, or air-compressing fan at the mouth of the inlet
shaft. By either of these methods a different state of tension
is produced in the two shafts connected below, and, in the
effort to establish equilibrium, the air is set in motion, a draft
is created, and a current is established that flows through the
air courses at a velocity dependent upon the head due to the
difference in pressures, as has been seen in 45.
Furnaces are employed for increasing the temperature and
are constructed in such manner as to be remote from direct
contact with the coal, yet in close proximity to the shaft which
constitutes the outlet for the mine air, and in a gallery through
which circulates air from the workings. The pit selected for
the outlet should be that one which would naturally carry the
flow in winter. The furnace is simply a fireplace, walled and
roofed by a fire-brick or common-brick arch (Figs. 100 and
10 1). When special care is taken, a second wall is built out-
side and over, with an air-space between, to isolate it from
the coal and prevent fire. If the roof is wet, a double arch
must surmount the furnace, as otherwise the steam generated
will burst the arch. If the mine is fiery, or considerable dust
is floating, care must be taken that the gases are well diffused,
or else the current must not be brought into close proximitv
with the fire. In such cases the current is split, a small por-
tion being heated over the fire, the remainder passing through
METHODS OF VENTILATION.
247
a " dumb-channel," entering the upcast 50 feet or so above.
A stil) safer plan passes all of the fiery current through the
Fig. 100
channel, and feeds the furnace by a split current of fresh aii
direct from the intake.
The size of the grate depends upon the work to be done
Its bars are 3 feet from the floor, slanting upward toward the
MOOa dOOH_
Fig. loi.
shaft T to 6, distance to the roof 4 or 5 feet. The width
wall towall> is 6 feet and its length from 4 to 12 feet, accorn-
in^' to the volume of air to be moved, which is about 150^
248 MANUAL OF MINING.
cu. ft. per square foot of fire surface on a properly constructed
furnace.
An ordinary furnace of 34 sq. ft. heating-surface, costing
$130, will heat a column of air such as will furnish 29,000 cu.
ft. per minute. A large number of furnaces 10 X 12 furnish
200,000 cu. ft. The cross-sectional area must be 50 per cent
greater than the upcast air-way, and the shape capable o
regulation by double sliding iron doors, to produce varying
degrees of contraction and of combustion. The fire is spread
over its entire width, and over only as much of its length as
is necessary to furnish an adequate motive column, at a tem-
perature of 140° to 160° F. Emergencies, as low barometer
and high thermometer, and the cleaning of the grates, require
other and more heating-surface. The coal consumed is 2 to
5 tons per day, spread thin and evenly over the bars, and fed
from both ends, on a long furnace. This rate is 40 to 70 lbs.
per hourly h. p. of work done on the air. Attendance, etc.,
is $5 per day.
Q being the quantity of air in cubic feet per minute, W
the weight of a cubic foot of return air, T being the tempera-
ture, F.°, of the upcast air, and t that of the air in the return
air-way, the number of pounds of coal consumed by the
furnace per hour is
X = o.ooneWQ{T — f).
The area, F, of the grate-surface in square feet is about one
tenth of the hourly coal consumption, in pounds, and its rela-
tion to the depth, D, of the furnace below the surface is
known by the expression
FQP- 1,716,0004//?,
P being the manometric depression in pounds per square foot,
and Q., the volume of air per minute.
An arrangement which is so simple and so cheap in con-
struction besides being easy of management presents advan-
tages which have long commended it to mine operators;
nevertheless the difficulties with its use, the dangers which
METHODS OF VENTILATION. 249
attend the exposing of an open fire in gaseous districts with-
out the possibility of introducing a safeguard, tlie numerous
calamities traced to the furnace which has fired either the solid
coal surrounding it, the gases in the return-air, the timbers of
the shaft, or even the surface plant, and its lack of economy
in shallow pits, were soon made manifest. The atmospheric
changes of the seasons reduce its efficiency, a decrease in the
barometric pressure and an increase in the surface atmosphere
reduced the action of the furnace, and notwithstanding its
great superiority over many other mechanical appliances it has
gradually been supplanted by fans. The povi'er of the furnace
increases arithmetically with the temperature, and that with
the amount of fuel burned. The quantity of coal that can be
consumed upon a given area is limited. The resistance of
the mine (see 50) increases on the other hand geometrically
with the square of the velocity of the current, and it is there-
fore manifest that between the several conditions the fur-
nace limit is soon reached. Many furnaces may be cited
supplying to the mine over 200,000 cubic feet of air per min-
ute; and enormous as they are, their cost is very little less
than that of a modern fan of large size; but when we contem-
plate the huge pile of coal thus consumed for the production
of the current, we are forced to the conclusion that efficient
furnace ventilation is a luxur}' which the coal trade cannot
long endure. Perhaps as the depth of the collieries increases
to about 2000 feet that the furnace may be reinstated.
With the atmospheric air at 62° F. and the furnace-heated
air at 132° F., the Avater-gauge depressions, m, produced at
various depths of furnace are as follows:
D. m. I D. m.
50 feet, 0.086 inch, j looo feet I-73S inch.
400 " 0.694 " ' 2000 " 3-471 "
700 " 1.2 15 " I 4000 " 6.943 "
These are in accordance
the manometric depression:
W
1 84 ^ 46 1 -f^ Ti
These are in accordance with the formula for estimating
in =: U 1 -
250 MANUAL OF MINING
Ex. 20.— A colliery has two shafts 1000 ft. deep, 12 ft. in diameter; temper-
ature in the downcast is 60° F. ; barometric pressure is 30 ins. 150,000 cu. ft.
of air are supplied per minute by a furnace. Required the temperature of ihe
upcast and the horse-power necessary to produce ttie ventilation, the mine
being supposed to show a water-gauge resistance of 2 inches of water.
520 ' F., and 163.5 h.-p.
Assume the coefficient of friction for the smooth shafts to be as great as
that of the rough mine galleries; then
0.0000000217 X 1000 X 37.7 X (150,000)'
^ — = 12.8,
^- (ii3)»
Each shaft therefore offers a resistance equal to 12.8 lbs. per square foot. The
total resistance then is 25.6 + 10.368 = 35.968. The work done in ventilating
is 150,000 X 35,g68 = 5,395,500 ft. -lbs., or 163.5 horse-power.
The temperature of the upcast shaft is
P (461 + 7')35.968 r- 60
'^^ 39-759 521
Or, by another method : A cubic foot of air at 60° F. and 30° barometer weighs
0.0766 lb. 150,000 cu. ft. of the circulating air weigh 11,490 lbs. Since the
furnace is performing 5,395,500 ft. -lbs. of work upon 11,490 lbs. of air, the
height through which it is moved is 470 ft. in one minute. Then M is 470 ft.,
t = 60° F., and £> = 1000 ft.
From this it is seen that the temperature of the upcast air necessary to force
150,000 cu. ft. of air through the mine is dangerously high. The furnace must
be replaced by the exhaust-fan, or the frictional resistances must be reduced by
enlarging the entry-ways.
What should be the size of the air-way shafts in the above case, that the up-
cast air be not hotter than 190° F. ? By substitution above, 3f is found to be
200 ft. ; the work is then 11,490 X 200 = 2,300,000 ft. -lbs. (70 h. p.). This value
requires that /> should not exceed 15.3 lbs., which limits the shaft's resistances
to 4.932 lbs., or 2.466 lbs. each. In order to obtain so low a friction, the areas
are enlarged to a radius of 16.66 ft.
pa" = fliiuf, or p{Tlr''f = fl{21tr)q'.
47. Mechanical ventilators include a variety of devices,
of which fans remain our main reliance at the present time.
As the furnace has in the past supplanted various mechanical
devices in the form of pumps and trompes, so fans built on
various principles have succeeded the furnace and the steam-
jet. There are two classes or types of fans: (i) blowers, either
rotary or reciprocating, and (2) fans, propeller or centrifugal.
METHODS OF VENTILATION, 25 1
Those of one type sweep out a fixed volume of air at each
revolution and are known as the definite-volume exhausters,
under which head come the Root, Baker, Lemielle, Cooke,
and Fabry. In the other class, acting centrifugally upon the
air, we have a simple revolving wheel always working in one
direction, producing by its rotation a pressure or a rarefaction
the degree of which depends upon its speed. Of these we
have the Guibal, Waddle, Walker, and Schiele ventilators.
The trompe is a simple application of the injector princi-
ple, — water falling in the cylinder and carrying with it air,
creates a small intake draught. The volume of air, compared
with the quantity of water used, is so insignificant that,
unless an especially favorable means be provided for carrying
off the water, the ventilation is too expensive to be con-
tinued except as a temporary expedient.
The blowers, either rotary or reciprocating in their action
are of general use in America, being represented by the l^oot,
Baker, and Champion on the one hand, and air-compressor
and other reciprocators on the other. The blower forces the
air through the intake compartment of the mine, which dis-
charges it at , the upcast. These blowers or force-fans are
much in vogue for small workings and as expedients in fur-
nishing a separate ventilation for stopes and drifts; but few
are employed in coal-mines to produce the total ventilation
there required. In metal-mines, however, they are largely
depended upon, though they supply a pressure higher than
that ordinarily required to overcome the resistance of the
mine. They produce air by reason of their high speed at a
pressure often attaining ten pounds per square inch, whereas
a mine requires an initial pressure only sufficient to overcome
its resistance, which is rarely greater than ten pounds per
square foot of base. The blower is a small radial wheel
revolving freely in a casing and nearly touching its sides. By
a central opening on either side the air is admitted to be
acted on and set into rotary motion. These blowers may be
had in sizes capable of furnishing as much as 16,000 cubic feet
per minute, requiring from one to fifteen horse-power for their
252 MANUAL OF MINING.
operation. Some of the blowers are capable of a ready
alteration from a blower to an exhaust, or the reverse, which
fact recommends them particularly for wide shafts which are
liable to freeze during winter. This is particularly advan-
tageous in metal-mines, where it makes very little difference
which way the current moves. In collieries, however, as has
been seen, this is not feasible.
The Root blower or force-fan consists of two interlocking
impellers revolving side by side in very close connection,
without actually touching one another or the enclosing case.
They are made of cast iron accurately bored and dressed to a
true surface, so that, while practically no air escapes, there is
also no internal wear. At each revolution a definite volume
of air enters, is enclosed, and discharged either at the top,
the bottom, or the side. They are driven by a pair of
external gears, at a speed ordinarily of from 250 to 500 revo-
lutions per minute. The extremities of the revolving arms of
the impeller section are of an acorn shape, or their surfaces
are arcs either of true circles or of cycloids.
The Fabry, which resembles the Root blower, is much
used in the north of France and Belgium. Two fans, each
having three broad blades arranged radially, are hung in a
chamber. They revolve with equal velocities in opposite
directions, the blades coming in contact, isolating a quantity of
air, and expelling it into the atmosphere. The success of this
blower is attributed to the fact that there are no joints in it.
The Baker rotary force-fan has inside of its casing three
drums, each being an independent casting turning truly and
balanced perfectly to insure a steady motion. The upper
drum, which receives the power from the engine, does all the
work of blowing, while the two lower drums serve as valves
to prevent the air from escaping.
Cooke's is a positive machine. An eccentric drum revolves
inside of a 12-foot circular case very close to which is held a
swinging shutter that cuts off the entering — from the discharge
— current. The inlet and outlet portion occupies 235° of a
revolution. At Lofthouse iron-mines are seen two of these
METHODS OF VENTILATION. 253
side by side, the drums being placed opposite each other on
the shaft, so that the revolving mass is balanced, the discharge
equalized, and tlie efficiency raised.
The Lemielle is a species of rotary air-pump, complicated
and leaky, producing large volumes under great rarefaction.
It consists of a vertical cylinder, within which a second
revolves eccentrically; on this latter are two or more vanes,
which in one part of the revolution lie close to the shutter,
and in another open and expel the air.
The reciprocating blowers have been displaced almost
entirely by the rotary blowers, either class being capable of a
reversal of rotation to force air into or exhaust air from the
mine, as desired. The power required to drive the force-fan
depends upon the volume and pressure of air exhausted or
discharged; but the rule usually followed for computing the
net power in a given volume at different pressures is to mul-
tiply the number of cubic feet delivered per minute by the
pressure in pounds per square foot at the blower, and the
product by 0.00003; the quotient will give the net horse-
power required to drive the fan.
The centrifugal fans, which are used almost exclusively in
this country, may be divided into two great chisses; (i) those
which are called open-running, by which we mean that they
are free and discharge their air all around the circumference;
and (2) those called close-running fans, which have but a
restricted opening for the discharge of the air. Those of
either class are made large in diameter and are driven at a
relatively small angular velocity, though few, such as the
Schiele, are of small diameter, running at a high angular
velocity. They produce large volumes of air at a low pres-
sure, and may be reversed in motion to exhaust or to force
air. The diameter of the fans of this class may be and is
occasionally as high as 50 feet, those of small diameter being
regarded as unnecessarily cumbrous. The action of all fans
is based upon the general law that bodies in motion tend to
travel in straight lines, resisting any attempt at diversion from
this path, in consequence of which, when the fan is set in
254 MANUAL OF MINING.
motion, its blades come in contact with its interior air, the
particles of which are at rest and resist rotation. When,
however, the particles do move, their endeavor to travel in
straight lines results in their making for the circumference,
producing thereby in the central portioa of the fan a partial
vacuum, which is replaced by the air external to the fan. So
long as the rotation of the blades continues, so long will this
current be produced and maintained, the pressure of which
will increase as the peripheral speed increases.
Fans which are of the open-running variety include the
Waddle, Biram, Naysmith, and Hopton, all of which are
essentially similar to the first named. The Waddle is a self-
contained fan in that there is no fixed casing, and the whole
machine revolves. Its form is practically that of a light
hollow disk of wrought iron, the blades and casing being
wholly riveted together. The air enters by a straight lead at
one side only, and passes through curved and gradually
narrowing channels to the circumference, the blades being
bent at first to incline slightly backwards, the alternate blades
extending not more than one half the distance between the
circumference and the inlet. The passages, by their contrac-
tion, are so made that the circumference at any point multi-
plied by the cross-sectional area at that point is a constant
quantity. The outer circumference of the fan is bell-
mouthed.
A fan of 9 feet diameter circulates 80,000 cubic feet with
a water-gauge of 2 inches. One of 45 feet, driven by an
engine with 4.0" X 42" cylinder at a boiler-pressure of 80 lbs
per square inch, has given a volume of over 550,000 cubic
feet at 42 revolutions.
The Hopton has an inlet on each side of the central
diaphragm with backward-curving blades, and a construction
very simple. The revolving portion consists of the arms and
blades working between two brick walls.
The open-running fans must, in order to be ef^cient, dis-
charge their air at a very low velocity, because the energy of
bodies in motion increases as the square of the velocity, and
METHODS OF VENTILATION. 255
that passed by the discharged air is, therefore, so much use-
less work. It is for this reason that the passages in the more
correct open-running fans, Hke that of the Waddle, are curved
backward. The theoretical depression which can be produced
in fans of this type is equal to the height due to its peripheral
speed, T, in feet per second.
i/= T' ~ 2g^ o.oi553r\
The closed-running fans are essentially of a more massive
structure than those of the open-running type, being of con-
siderable width as well as of diameter. Of this class of fans
the Guibal is a type, the Scheile and the Walker Intlcstructi-
ble being similar in construction. Inside of a fire-proof hous-
ing a horizontal shaft is revolved b)' an engine or dynamo,
carrj'ing \\'ith it an hexagonal or square frame, on which are
built six or eight blades. The blades are flat and slightly
curved at their tips, sometimes radially and often inclined
backwards. The clearance between the tips of the blades and
the casing is made as little as possible, except for a certain
distance at the bottom, through which the air is discharged,
the amount of that opening being regulated by an adjustable
shutter in a gradually enlarging chimney. The air enters at
the centre, whence it passes into one of the intervals between
the consecutive blades which form an c'vasc'c canal, the speed
of exit being less than the speed of entr)? (Fig- 102).
In the Scheile fan the blades are contracted in width from
inlet to outlet, the fan being surrounded by the usual spiral
casing, into which the air discharges all around the circumfer-
ence, the space continually increasing until it reaches the
chimney. The blades of the Rateau fan extend to the centre
of the fan, and have a peculiar curvature slightly forward, and
also a curvature in the line of the fan-shaft. Immediately in
front of them is a cone terminating in a point. The Capell
fan, of equal power with the Guibal, is smaller, and runs at a
higher speed. It has two concentric shells besides its outer
casing, in each of which are curved blades with the convex side
2t;6
MANUAL OF MINING.
forward. The air enters the inner shell, is forced out through
ports into the second outer shell, where it strikes the concave
face of the outer blade, and thence is discharged at a low
velocity through the usual expanding exhaust-flue.
'wr m
?\G. ro2, — Figures of Working Drawi^'GS of Fan.
The special improvement giving rise to the name of
"anti-vibration shutter" is made after the manner of an
inverted elongated V, and constitutes the characteristic of the
Walker fan, in which the injurious rebound produced with
every revolution of the blade in the similar types of fan is
remedied, thus enabling a higher speed with less wear and
tear, and a practically silent fan.
The Champion fan, which is really two fans joined
together by a common centre ring, is designed to propel the
air with a minimum resistance, the blades having a backward
curvature. The use of the inner casing or hood and attendant
diaphragm, which are hung on frames, renders it possible to
change the current at will, blowing to exhaust, by revolving
the hood around the fan without stopping the latter.
The theoretical depression produced by a covered venti-
2"
S
1 Dia.
-rl h : I 111 X i-j
H
I
O 8
c
a
33
-<=4=4'
>
-/--"
#
--
it
-
!'i^
^.11^. ;.
^i
^TTjiEE^SEKKi^SjyEB-SEajIS
to
CI
METHODS OF VENTILATION. 259
lator with an expanding chimney is twice that of the unc(j\ -
ered or open-running type, and is equal to double the heiglit
due to the tangential speed of its blade-tips. The use of the
chimney gives to this type of fan the enormous advantage
over the other that the air may be discharged from the fan at
a higher velocity without any material loss of energy. The
gradually increasing space into which they discharge reduces
the velocity and utilizes all the energy in giving motion to
the air, while the air is ultimately sent out into the open at
such a speed that no resistance practically is experienced.
The fans of either type are of dimensions as large as 50 feet
in diameter and 12 feet in width, those of the open-running
class being comparatively very narrow. The volumes which
these fans will produce vary directly as the speed of their
rotation, and their depression varies as the square of the
speed of rotation. Though they may be run at any speed at
will, the efificiency of the fan materially decreases when the
speed of the tips of the blades exceeds, to a great degree,
5000 feet per minute, or is less than this quantity. The
rate, however, whicii is regarded as normal is 4000 feet of
peripheral velocit)' per minute. Below or above the normal
speed a loss of velocitj' ensues in the discharging air, which
alternately is expelled into the chimney or carried with the
blades into the fan, there to repeat its circuit. The discharge
is frequently followed b}' a vibration in the fan, to remedy
wdiich the sliding shutter (ab. Fig. S6) is introduced. Its use
permits of a high speed and efficiency; and its correct posi-
tion is only known by experiment in each individual case, to
determine by the point at which the throbbing ceases with.
the given speed. Numerous experiments have Ijeen cim-
ducted upon centrifugal ventilators witli the view of determin-
ing the influence whicli the various dimensions of the fan and
o
shapes of its parts will have upon its performance; antl the
following conclusions arc cited from the results of the tu-ts
made by R. Van A. Norris, Wilkesbarre, Pa., upon 25 fans,,
as the influence of : " ist. The diameter on their performance
seems nil; the only advantage of large fans being in greater
26o
MANUAL OF M/lVING
width and a lower speed required of the engines. 2d. Width
upon efficiency is, as a rule, small. 3d. Shape of blades
shows that the back curvature is better, and diminishes the
vibration. 4th. Shape of casing is considerable. The proper
shape would be one of such form that the air between each
pair of blades would constantly and freely discharge into the
space between the fan and casing, the whole being swept to
the cvasce chimney. A large spiral, beginning at or near the
point of cut-off, gives in every case a large efficiency. 5th.
The shutter on the fan is beneficial. The exit area can be
regulated to suit the varying quantity of air, and prevent re-
entries. 6th. Speed at which the fan is run. The efficiency
is high if the peripheral velocity is large."
In many states the law recjuires all ventilators to be
provided with a recording instrument by which the number
of revolutions of the fan shall be registered every hour and
such data to be taken and reported. In other states also is
required an automatic regulator for the water-gauge. The
speed-registers are generally constructed of a metal pedestal
erected on blocks at the side of the fan or engine-shaft,
a small vertical shaft to which a governor is attached. A
small cog-wheel on the lower end geared to a large driver
on the fan or engine-shaft communicates the speed to the
governor, which, by a system of leverage, raises or lowers
the arm to which is attached a pen that presses against a
paper dial lieid in position by a light case of sheet brass.
The higher the speed of the fan, the more will the governor
raise the lever, and consequently the pen register. The
time is recorded by a clock to whose shaft the dial case is
attached. In other devices the dial case is a cylinder in
which is rolled a sheet of paper turning on a horizontal axis,
which is also the continuation of the shaft of the clock. These
instruments perform the work expected of them with great
satisfaction.
The ventilation of a mine by a fan is affected by atmos-
pheric changes in a manner similar to furnace-currents, a low
barometer or a high temperature requiring an increased de-
METHODS OF VENTILATION. 2t>l
gree of rarefaction from the fan or furnace. Moreover, as
the depth of the mine increases the work devolving upon the
fan proportionally increases, because normally the air becomes
denser; with every additional thousand feet of depth, an
increased rarefaction or depression of 0.4 inch of water-
gauge is necessary. Compared with the furnace its efficiency
decreases with the depth of the upcast until, at a certain
depth, it becomes an open question between the relative
merits and demerits of fan and furnace, as to which will be
-he more economical. For shallow works, the exhaust-fan
undoubtedly takes precedence. At the depth of a thousand
feet a large furnace will equal a very imperfect fan, consum-
ing 20 pounds of fuel per hourly horse-power ; a good fan and
condensing engine will be cheaper than a furnace down to
the depth of about 4000 feet. Taking cognizance of the
objections to the furnace, it must also be borne in mind that
machine ventilators are subject to serious objections, since
during the time of their repair the mine must remain unven-
tilated, whereas with a furnace after its fire has been extin-
guished a considerable circulation will still continue in the
upcast for some time. Auxiliary ventilating appliances should
be supplied against any emergency which arises during the
repair of the fan.
48. The theoretical depression of a fan is the height of a
motive column of the density of the flowing air and is equal
to the ventilating pressure exerted by the fan, friction being
left out of question, whether of the mine or of the fan and its
mechanism. An ideal ventilator will produce a depression
which is twice the height created by the tangential speed of
the tips of the blades. If, then, 7/ be the height of the
motive column due to the velocity, T, of the fan tips in feet
per second, 77 will equal ; but imperfections of detail pre-
vent such an initial depression being attained, and represent-
ing them by a coefficient K, which is always less than unity,
— reaching 0.85 in Guibal fans, but more often being below
0.6 in the average construction of fans, — the fan approaches
262 MANUAL OF MINING.
an ideally perfect one when K approximates to unity. The
yield of the fan then in barometric depression, or its useful
effect, is // = . Various enfeebling causes modify the
i.
capacity of the fan to determine the value for K. The
quantity of air which passes through an orifice is equal to the
product of the area and the velocity when no friction is
encountered; but when any fluid flows through an orifice in
a plane surface a considerable diminution of the discharge
takes place, because the directions of molecular flow converge
and produce a contraction of stream. The coefficient corre-
sponding to this contraction, known as the vena contractu,
is 0.65 ; hence with a given velocity, T, and a head, H, under
the conditions modified by the coefificient K as above, the
discharge of air per second will become
q = 0.9194(7 VKT\
Hence it is evident that if the capacity of the mine is such
tliat it is incapable of delivering to the fan the volume of air
equal to the body capacity of the latter at a given speed, the
frictional resistances encountered in the mine will reduce the
efficiency of the fan by some quantity which is usually com-
prehended in the symbol a, representing the area of the mine's
"equivalent orifice" in square feet. E.xperiments have
demonstrated that when a is 20 square feet, only 65,000
cubic feet of air are obtained per minute for the fan peripheral
speed of 5000 feet per minute; but when the mine resistances
have been reduced until its "equivalent orifice" is as large as
100 square feet, 280,000 cubic feet of air are obtained from
the same speed of fan. The value of this fiction, which in
earlier days was known as the temperament of the mine,
enables us to grasp the conditions under which the ventilator
is working.
In like manner the equivalent orifice of the fan, which is
designated by the symbol 0, may be determined. It meas-
ures or represents the orifice in a thin plate which offers such
a resistance to the flow of the current, Q. as is equal in effect
METHODS OF VENT I LA TlO^f. 263
to the aggregate resistances encountered within the fan from
its imperfections. If H is the theoretical depression which
the fan should produce when moving at a tangential speed,
T, per second, and li represents the actual or the effective
depression which is produced upon the air as measured by the
water-gauge, then H — h \s the head wasted by the fan in its
construction and may be represented by h,^, which measures
the head corresponding to the equivalent orifice. In large
fans its value varies from i6 to 80 square feet.
The head lost in the fan, represented by /;„, is equal to
H — h, the velocity due to which may be determined by the
expression
V„ = V2g/l,.
As the value of /i„ approaches zero and that of /i approaches
J/, the fan approaches an ideally perfect ventilator. The
actual velocity through the orifice of entry is 0.65z'„, whence
the area of the orifice o, which equals the quantity flowing per
second, divided by the velocity of the flow, has the following
value:
9
0.65 \/2g/l^ V 27.87/^.
The density of water being 833 times that of air, the ratio
between the water-gauge reading and the height of the
motive column, //, is i : 833. To convert the water-gauge
reading to a height H of air-column of equal weight in feet,
the height of the water-gauge, in, in inches is multiplied by
69.4.
The ratio between the lost head in the ventilator and the
effective head represented by the water-gauge is expressed in
the equation
-r = -T, and n = N — k^r,
k o
whence
/- ""^
It- 3 1 « •
o -\- a
264 MANUAL OF MINING.
The quantity of flow through the mine and also through
a fan, depending on the relations which the area of the mine
air-ways and the condition of their rubbing surface bear to
the mechanical condition of the fan, is manifestly dependent
upon a proper ratio of a to 0, which ratio may be expressed
as the "appropriateness of the fan to the mine." When this
value is equal to or greater than unity, the fan would be too
small for the mine, and it is questionable whether any air
would flow under those conditions. As the ratio becomes
smaller, the conditions become more favorable for the fan.
When approximating a ratio of 0.3 the orifice of discharge of
the fan is to be considered as having a fair working ratio.
More air is obtained by a given fan and at a given velocity
when a is large than when a is small, for, no matter how well
constructed the fan may be, it cannot provide a quantity
equal to its body capacity unless the mine can pass this
quantity. The effective work done upon the air is less in the
latter case than in the former for a given volume of air. The
mechanical work of centrifugal force is 0.0000340(7"^ — V^^.
In this T is the circumferential velocity and F^ is the absolute
velocity at expulsion, due to compression from centrifugal
force. As V^ increases, so the work on the departing air, and
proportionately the effective work, decreases. The use of
the funnel-chamber reduces this quantity to \ or \, and the
work lost to 4 or 5 per cent.
The efficiency of the fan is measured by the ratio between
the actual centrifugal pressure, /^, and the effective pressure, /.
The mechanical efficiency is also measured by dividing the
horse-power in the air by the engine-duty. With fans
properly constructed, the efficiency approximates about 68
per cent. In experimentally measuring the efficiency of a
fan, it is customary to determine the dynamometric resistance
and internal friction when its orifices have been cut off from
any communication with the mine, the air being then drawn
from the atmosphere and, after passing through a fan, expelled
at its throat. Counting the rate of revolution and estimating
the volume of air which is moved, the power necessary to
METHODS OF VENTILATION. 265
overcome this friction is determined and expressed in feet of
the air-column whose weight equals the aggregate friction.
This quantity divided by the theoretical head corresponding
to the velocity of the fan determines its ef^ciency under the
conditions named. The fan is giving its maximum efficiency
when "its body capacity just exceeds the quantity the mine
will pass at a gauge pressure, F, due to the speed of rotation
of the fan.
49. In designing a fan to give an ample service to the
mine, the essential elements are Q and ;;/. These given, the
diameter, the peripheral speed, and the length and width of
blades, as well as the direction of their inclination, must be
determined by the engineer. As to diameter, it may be said
that the slow-running fans are regarded as cumbersome and
costly, requiring expensive foundations. Large fans may be
run at a lower rate of revolution and produce the same tan-
gential s[3eed than would a fan of small diameter. Insomuch
as speed is the important factor in the construction of venti-
lators, due consideration must be given to this questlLUi, which
is determined by local conditions of place, economy, and
mechanical simplicity. A convenient rate of revolution for
a fan directly connected with the engine is about 60 per
minute. The body capacity of the fan should be large
enough to maintain the required pressLire, /-', without great
variations in speed. Though the practice of European
engineers tends toward the rate of tangential speed which
represents 5000 feet per minute and over, in this country
4000 may b- considered as normal. In any event, if the
calculation and design be made on the assumption of either
normal speed, it will be possible, when an emergency arises,
to increase the speed sufficiently to give a volume nearly one
tenth greater than the normal quantity. Moreover, when
the rm'ne is dry and dusty it will be possible to turn the
whole volume of the excess into anv or each single split,
through which it may be drawn, clearing av,'ay fine dust and
moisture.
The entry for the air should be made easy and large.
266 MANUAL OF MINING.
preferably divided into two inlets, one on each side, with a
diaphragm to prevent the currents from conflicting. This
necessitates a wide fan, which, however, gives a volume pro-
portionatelj' greater than what is to be had from a single fan
with a single large inlet.
The length of the blades of the fan should be only a little
greater radially than the difference between the radii of the
fan and its inlet. With a large inlet the blade necessarily is
shortened, and when pressure is desired the blade length
should be increased to as large a quantity as possible by pro-
viding two inlets. Notwithstanding that the width of fans
is much greater than would be obtained by substitution in the
formula; following, it is certain that the latter dimensions
correspond to a greater efficiency. M. G. Hanarte concludes
that "the Guibal fan has always been eight or nine times too
wide, and the Capell is nearly as bad."
The shape of the blade should be such as would present to
the circumference of the outlet an inclination following the
resultant of the movement of rotation and of the movement of
the air penetrating the spaces between them. The blades of
open-running fans curve backward. The backward curvature
is conceded to give a freer delivery, and the forward curvature
at the tips a higher water-gauge pressure. The number of
blades is seemingly a matter of indifference, though the limit
may doubtless be determined by the inevitable friction pro-
duced by the excessive surface of contact when too numerous.
The friction varies as the cube of the section of space between
two vanes. As to the shape to be given to the casing, it will
be noticed that the original Guibal fan had no spiral, the tips
of the blades revolving but two inches clear of the casing, and
the spiral enlargement beginning at the angle of about 67° 30'
from the lower vertical radius. Those fans presenting a Iar"-e
spiral beginning at or near the cut-off and increasing about six
inches for each 45° up to 275°, and thence widening by an
increasing increment to the e'vase'c chimney, appear to o-ive
larger efficiency by allowing for the slackening of the speed
<)f the air, and discharge the air with less energy at the exit.
METHODS OF VENTILATION. 26/
M. G. Hanarte concludes that the spiral envelope is not
necessary.
Below are given formulae for the computation of dimen-
sions of a Guibal fan in accordance with the data indicated
above. All dimensions are in feet.
/' = diameter of the fan between the blade-tips : Q -^ 200 = i" ;
/ = length of the blades in feet ;
r = their radial length = 2.6i/« ;
X =^ their width z= A ^^ 27ts ;
A = aggregate area of the one or two inlet-ports in square feet (radius of each
central inlet, s) ^^ Q -r- 1300 ;
A" = number of revolutions per minute ;
T = peripheral speed of fan per second ^ DN^ ^^ 19.0985 ;
V ^ theoretical velocity per second due to head //;
I'l = velocity of the centre of gyration of air-column between the blades
= Tr(D — r)N -=- 60 ;
p = radius of gyration of the mass of air = i^iD — r).
IV = weight of the unit of revolving air-column per foot of fan width
= o.0766r ;
/• = centrifugal force of the air-mass in pounds per square foot of discharge
area or of the housing =; ^Vv,"^ -i- itg = o.oooysySrz'i^ ;
,, I ■ 1- ■ I- u A ,/(/''—/) 1,800,000
^'.2 = velocity of air discharge per second = 4/ ^^ •
' 2130 +/'
Z =: minimum area of discharge-port = ,-? -^ 2;
//o = fan resistance, measured in feet of head, = j¥ — /; ;
(' = area of orifice offering a resistance to the flow of Q cubic feet of air per
minute, equal to that of the fan ;
q = quantity of air discharged by the fan per second in cubic feet = o.65z/,s;
Q = quantity of air discharged by the fan per minute in cubic feet — 60^ ;
m = mine resistance in inches of water-gauge ;
P = mine resistance in pounds per square foot =; 5.184 m-
In Figs. 103 to 106 are illustrated the details of the
ordinary pattern of fan which is designed in accordance with
the conditions indicated above. As, fortunately, neither the
Guibal fan nor the shutter is subject to patent, the working
drawings here given may aid the construction engineer.
When the conditions are satisfied by the revolution of the
fan of proper proportions, the centrifugal pressure of the fan
should produce a depression, F, equal to or exceeding P, the
mine resistance, in order that the requisite discharge through
the outlet should equal the desired quantity Q. When it is
discovered that the volume of discharge is deficient, the fan
268
MANUAL OF MINING.
SECTION THROUGH A-B DETAIL SECTION OF SHUTTER
'iron J»c- i K> / strap iron.
4 THUS
Fig. 105.
METHODS OF VENTILATION.
269
dimensions Z? or r should be enlarged or the rate of revolu-
tion increased. Below is a brief tabic indicating the theo-
retical water-gauge depression in inches for the corresponding
peripheral speeds in feet per second.
T
TH
49-2135
1.084
56.103
1.408
63.321
1.794
66.930
2.004
76.117
2-593
T
82.023
m
3.008
88.588
3-510
94.818
3-967
00.078
4.481
06.301
5.056
Example. — Required the dimensions of a fan to provide 125,000 cubic feet
of air against a mine resistance of 2.5 inches.
At a normal rate of 65 feet per second, the diameter becomes 25 feet ; the
area of the inlets is q6 square feet, the diameter being 11 feet ; the radial length
of the blade is 6.5 feet ; the minimum width of the blade is to be 2.S feet.
As fj = 9.25 feet and I'l = 51 feet, the centrifugal pressure. /", becomes 12.7
pounds per square foot of radial column ; and the velocity of discharge 31.6
feet per second, uhich with a minimum area of discharge-port, Z., of 4S square
feet, would furnish less than 60,01.0 cubic feet. The mine resistance exceeds
the standard allowance of one inch of water-gauge for each one hundred
thousand cubic feet of air. The mine air-ways should be enlarged or the fan
operated at a higher speed. An increased rate of 70 revolutions per minute
will produce a ventilating pressure of 22 pounds per square foot. The blades
may be lengthened and two inlet orifices be providetl, each of 43 square feet in
area.
At the peripheral velocity, T, of 91. 66 feet per second the theoretical head
of discharge is 261 feet. Kut the effective head, A, against which the fan is
operating, measured by the water-gauge, is 166.66 feet. Under the conditions
of operation, therefore, the loss of head, Ao , in the fan is 94.34 feet ; since the
equivalent orifice of the mine is 21.2 square feet, the equivalent orifice of the
fan O, is 41.2 feet. The ratio of a to O, nearly one half, represents a fair
working ratio of appropriateness of fan to mine.
The following references are cited:
A'J!er. Inst. M ., E,: The Heatof the Conistock Lode, John A. Church
E.M., Ph.D., VIII. .324 ; The Heat of the Comstock Mines, Prof. John
E. Church, E.M., VII. 45, 54; Centrifugtil Ventilators, R. Van A. Norris,
XX. 637; Fan Details, Shatter. Edwin R. Walker, XIX. 37.
Trans. M. &^ M. E>IK-' Electrically Driven Fan, H. Allans, April
1897. XLVI. Part 3. 47.
U. S. G. S.: Temperature of the Comstock Lode, E. Lord. IV, 390;
Temperature in the Mines of Grass Valley, W. Lindgren. 17th Annual
ReiJ.. p. 170.
270 MANUAL OF MINING.
Mineral Industry : How Deep can we Mine? A. C. Lane, IV. 767.
Amer. Mfr.: What is an Effective Fan? W. Clifford, Jan. 1897.,
121, etc.
Coll. Eng.: Fans in Metal-mines, Albert Williams, Jr., May and June
1896, 230; Underground Temperatures, editorial, XVI. 250.
Coll. Guard.: Rate of Increase of Temperature with Depth, LXXII.
224, 317; Fan-construction Design, M. G. Hanarte, Mar. 1897, 505;
Fan-construction Design, H. Heenan and Wm. Gilbert, April 1S97,
720; Design, Dimensions, H. Heenan and Wm. Gilbert, April 1897, 763 ;
Discussion of Fan-construction Designs, J. Boulvin et al., April 1897,
809; Discussion of Fan-construction Designs, M. Imray^/a/., May 1S97,.
870; Body Construction of Fan and Water Gauge, G. M. Capell, May
1897, 994; Laws Governing Useful Work of a Fan, M. G. Hanarte, Mar.
'897. 55^; Laws governing same, H. Heenan and Wm. Gilbert, April
1S97, 720; Fan-Power, Steam-engine Cards, M. de la Collonge, Mar.
1897, 504; Fan, Power, Volume Furnished, M. G. Hanarte, Mar. 1897,
552; Instruments for Determining Underground Temperature, B. H.
Brougli, Dec. i8g6, 1171; The Formation of Coal and Generation of
Fire-damp, M. F. Rigaud, Sept. 1897, 463; Furnace air-circulation,
H. W. Halliaum, Aug. 1897, 285, Experiments on Centrifugal Fans,
Bryan Donkin, Sept. 1895, 505; Fan-gauges, G. M. Capell, 1897, 489
and 1 16.
Coll. Algr.: Descriptive Lecture on Fans, C. M. Percy, 1S94, 56;
Fans, Tests with Various Types of, J. P. Houfton, May 1893, 83, and
Nov. .893, 202; Virtues and Vices of a Furnace, C. M. Percy, 1894, 55.
Fed. Inst. M. E.: Comparative Experiments upon a Capell and
Schiele Fan working under Similar Conditions, Maurice Deacon, I, ;
Manometric Efficiency of Fans, G. M. Capell, IV. and V.
Ren. Unh'.: Note sur la theorie des ventilateurs a force centrifuge,
D. Murgue (2 Serie) XXII. 564.
N. E. I.: On tlie Construction of Ventilating-furnaces, J. Daglish,
IX. 131 ; A Comparison of the Lemieile and Guibal Systems of Mechani-
cal Ventilation, Wm. Cochrane, XVllI. 139.
CHAPTER XIII.
DISTRIBUTION OF THE AIR.
50. Calculation of the work done in ventilating a mine ; losses by friction;
coefficient of friction; formulae; examples; similarity between the
formulae for frictional resistances of water, air, and electricity;
examples and illustrations. 51. Interpretation of water-gauge read-
ings; formulae; examples; Buddie's system of splitting air-currents ;
advantages and economy of the plan ; principles of dividing air-
currents into panels; formulae; laws governing the area of airways;
dangers of goaves, and the necessity for their isolation. 52. Velocity
of the air and the modes of measuring it, by candle, smoke, or
anemometer ; place for observation ; calculation of the ventilating
power. References.
50. It has been assumed thus far that the work done upon
the air is totally effective in the mine ; that with a given M
and P the calculated quantity of air is obtained without any
loss; that the momentum, once imparted to the air, would
carry it through the mine and out. This is not so. Friction
instantly overcomes the momentum ; the velocities given by
the formulae (Lecture 47) are never realized in practice. The
rough sides of the galleries and rooms, their sharp corners, and
the diminished areas offer resistances to the passage of the
current that consume often 90 per cent of the power. More-
over, the subtle air under pressure seeks to escape at every op-
portunity, and some portion of the precious fluid is lost into the
goaf, through doors and at crossings. A certain mine theoret-
ically required a pressure of but 1.2 lbs. per foot to give rise to
its current, yet the friction was such that 1 1.8 lbs. were actually
necessary to create the velocity. Not infrequently the ratio
between M (to which the generation of the final velocity at the
top is due), and M' , the head actually necessary to overcome
resistances, is as low as i : 18. In other words, only 5.5 per
271
272 MANUAL OF MINING.
cent of the work done upon the air is usefully expended. Any
means of reducing this loss is to be welcomed.
Let us examine into the laws governing the movement of
fluids and their applications to the conditions, that we may-
learn to reduce this friction to a minimum, and obtain salu-
brity, safety, and economy with the least outlay. The air
.vliich enters the mine from the downcast is distributed to the
rooms and chambers in proportions varying with their several
needs ; or the current as one mass sweeps through the main
way, along working faces, thence by return air-way over the
furnace or to the fan. The resistances encountered depend
upon the ratio of the area of the surface rubbed to the area of
the conduit, and upon the coefficient of air-friction against
rock. A satisfactory value for the coefficient has not been ob-
tained : the records of experiments show it to vary as in water,
according to the nature of the conduit and the velocity of
the flow. The coefficient varies with the nature of the
rubbing-surface, and consequently differs in various air-
passages of the same mine; nevertheless, the numerous ex-
perimenters have announced values for the coefficient of
friction of air in mines for each foot of rubbing-surface and
for a velocity of one foot per minute as varying between
0.000000008585 and 0.0000000219, with the preference
given to the latter quantity. This value fory, the coefficient,
is measured in the pressure per square foot in decimals of a
pound. jVleasuring the height of an air-column in decimals
of a foot, the value for the coefficient of friction/' has been
found to be 0.00000010635 to 0.0000002688 I, the two
extremes of values for /' being heads of air-column corre-
sponding to the values given for dynamic pressures, f. The
latter values, in both cases determined by J. J. Atkinson, are
most frequently used, and though higher than any of the
values ascertained by other experimenters, err on the side of
safety, and hence are accepted as the constant coefficient.
Let / be the length, m the perimeter, and a the area of the gangway, through
which the air is coursing at v feet per minute, and the rubliing friction is found
experimentally to heflifni^. Imagine a piston, fitting airtight in the passage;
DISTRIBUTION OF THE AIR. 2"/.%
to just move it against the resistance requires ttie expenditure of a.iorcepa,
in units of lbs. and sq. ft. Therefore the loss of power due to friction is /ia =
flmv' . , , flm(y
//wjz/', and the loss of head in feet,/ =^^^ , or in lbs.,/==^ — ^ — .
This cannot be ignored, for, other things being equal, the
quantity of air received at any face is inversely as the resist-
ances encountered on the way. In the "splitting" of the air
it is of special import. It will be observed that the frictional
loss is directly as the perimeter and inversely as the area. This
would suggest the desirabilit)' of selecting such a shape for the-
air-way as will make it as spacious as circumstances will per-
mit, consistent with a diminution of the exposed surface. The
circular form most nearly meets this requirement ; but, as a
rule, we are restricted to the rectangular or the more advan-
tageous trapezoidal cross-sections. Two galleries 5X5
require one third more power to carry the same amount of
air as a 5' X 10' gallery. It will also be noted that in;
galleries of equal cross-section the volume of air passing
through them having the same resistance will be inversely as
the square roots of their lengths. The gallery which is 1600.
feet long and carries 6000 cu. ft., offers the same resistance
and consumes the same amount of power as one of equal area
711 feet long, delivering 9000 cu. ft.
The friction increases with the square of the velocity. So
it would be far better, desiring a given quantity per minute
{Q = va), to increase the area rather than the velocity. Con-
versely, a local contraction of the air-passage, by the use of a
partly opened door, a pile of waste or of gangue, will materially
diminisli the air passing thiough it.
A coiniiarison of the above formula for air with those for
electricity and water \\\\\ show an identity of loss, though in
different units; lor electricit)- it is /' = C^R ^= fLC -r- a; in
which C represents the quantity of electricit}' flowing through
the wire; and for water Kutter's tormula for determining" tlie
resistance to its flow in pipes is a = cliitv".
5 I . It has already been remarked (44) tnat the water-gauge
measures the drag of the air in the mine, and thus serves to
274 MANUAL OF MINING.
indicate the pressure and head corresponding to the motive
column M. The pressure varies from f" for easy to 4" for
difficult ventilation (from 3.9 to 20.7 lbs. per sq. ft.). In an.
thracite mines it is about 2". The motive column, which is to
just maintain this pressure against resistances, should also be
sufficient to create a final or exit velocity in the shaft. If the
entire current traverses the mine unbroken, the resistance in
the shaft or entry is only a fractional part of the mine friction
indicated by the water-gauge, and the following formulae ap-
ply with sufficient accuracy :
flm ^ flin '
The value for /is to be taken always in the same terms
as that for/. In other words, if the mine resistance,/, be
given in pounds per square foot, the corresponding value for
/is taken as equal to O.00000002 19 ; or if the value for / is
given in feet of head of motive column, ]\I, the value for /is
then 0.000000269.
If the air-ways in the mine, the resistances of which are
to be calculated with a view to determining the necessary
ventilator pressure to produce circulation, are all of the same
dimensions, the calculation of the lost pressure may be made
in one operation by proper substitution for the length, periph-
ery, and area of air-way and the velocity or quantit}^ con-
cerned. The value of the frictional resistance, /, thus
engendered in the mine corresponding to the water-gauge
height. 111, and of the velocity of the air-current, added to that
of the pressure, /", requisite for the generation of the velocity,
determines the motor pressure required. Often /" is very
small compared to /, and may be even neglected without
sensible error; but when it is large the actual ventilatine
pressure, which must be supplied by the force-fan, or the
manometric depression to be produced by a furnace, or
exhaust fan, must be such as exceeds the sum of/ -J-/".
When the air-ways of the mine are of various cross-sec-
tions, the resistance offered by them in the aggregate must
DISTRIBUTION OF THE AIR. 275
be determined by adding together the separate values for/,
calculated for each differing cross-sectional area and length.
When the air-current is "split" into several smaller branches,
and circulated through an equal number of divisions of the
mine, more or less equal in length, with volumes of greater or
less velocity, the value for p must be calculated in each
division or district separately; and for each differing air-way
the aggregate resistance in each division is the sum of the
resistances encountered in each of its various galleries. The
■sum of the several frictional losses of head or of pressure, and
that pressure or head which produces the final velocity at the
mouth of the mine, is again equal to the ventilating pressure
demanded of the motor.
Formerly it was the practice to meander the air through
all the galleries of each lift before expelling it (Fig. 10). This
involved heavy pressures, enormous air-ways, or a velocity
dangerously fast, and the last gang, fed by the departing cur-
rent, would receive an irrespirable atmosphere, vitiated b)' the
emanations from all previous sources. There was nothing to
commend this pernicious system, and it is certainly' a matter
of congratulation that it is becoming obsolete.
Many years ago Mr. J. Buddie introduced a system of
ventilation for fierj- mines that has everything in its favor.
This system was known at first as " coursing the air," and
now is termed "splitting the air," the inception of \\hich is
due to Carlisle Spedding or his son of Whitehaven who intro-
duced it in 1763. By it the aggregate quantity of air is in-
creased, the dangers of explosion are lessened by confining
its train of evils to one portion of the mine, and power for
ventilation and haulage is saved, since it goes hantl in hand
with the method of panel-working (Fig. 12). Each panel of
the mine is completely isolated from the contiguous districts
hy barrier pillars, and is ventilated separateh' by deliver)- to
it i;)f a portion of the volume of the intake which does service
in that panel, to be afterwards discharged into the return air-
way, where it rejoins the exhaust from the other districts. The
electric distribution for purposes of illumination and the water-
276 MANUAL OF MINING.
supply of a town are conducted on identically the same prin-
ciple, i.e., that which recognizes the tendency of a fluid to
seek a shorter and easier escape from confinement. With a
number of conduits receiving at a common point a volume of
fluid from a larger conductor, each will convey a fractional
amount of that original bulk which is inversely proportional
to the resistance offered by its entire rubbing-surface. If the
several conduits again meet to discharge their individual
volumes of fluid at a common point into a common reservoir,
the pressure at the point of discharge is the same at the mouth
of each and every pipe. Likewise the pressure at the point
of union is the same in the ends of each and every pipe. The
loss of head or of pressure due to the flow of the given quan-
tity of fluid through each conduit is then the same. If the
original bulk is allowed naturally to subdivide, the amount of
fluid in the several branches will vary in an inverse ratio
with the cross-sectional area of their conduits. This is
equally true of the circulation of air through mine galleries or
districts, of water through branching pipes, or of electricity
through connecting wires in the circuit. In planning, there-
fore, the ventilating system for the mine which is divided into
a number of districts for ventilation purposes, the practice is
to calculate for each separate district its aggregate resistance
to the flow of the volume required for a known number of
men employed there, and for a dilution of the gases evolved
in that district. Several separate values for p are thus
obtained. But these district resistances must be equalized
or else the inlet-current will be so subdivided at the
point of distribution that the large bulk of the air will pass
through that district which offers the least resistance ; while
to that district offering the greater resistance the volume
there circulating will be small. This is usually the reverse of
the requirements; for, generally, that district offering the
smaller resistance is the shorter one, having less men in its
circuit, and therefore requiring a smaller volume of air; while
that district presenting the greater resistance to the flow of
the current is either more extensive, has a greater volume of
DISTRIBUTION OF THE AIR. 2/7
goaves, or contains more working places, and hence demands
a very large fractional part of the main current. In order,
then, to automatically deliver to that district requiring more
air, which at the same time offers a greater resistance, the
area of the conduit throughout its course or the area of the
orifice at the central point of distribution must be made
sufficiently large as to tempt through it, or into it, the
requisite amount of air, leaving to the smaller district, which
requires less air, an orifice of entry which is comparatively
small. By so doing the differences in pressure for each and
every district, between the point at which the splits of the
fresh-air current are made and the point at which the return-
currents from the same splits reunite, can be equalized to that
of the one offering the greatest resistance. Then the current
will naturally divide according to the areas of the inlets or of
the passages, and each district will receive its apportioned frac-
tion of the incoming air. Hence, whenever the ventilation of
the mine is to be split into several currents and the air is to be
apportioned in accordance with the demand, the mine foreman,
having calculated the relative values for the head lost in each,
determines by proportion, as will be seen, the comparative
area of inlet to be provided the several districts at the point
of distribution, and there, by means of doors and other regu-
lators, does so furnish to the given district the area desired.
The measurements of the water-gauge pressure or loss in
head between the beginning and the end of the split and the
velocity of the flow of air, are made in the intake; and while
it is not always possible to subdivide the current at a common
point of distribution, this should be done as near to the down-
cast as circumstances will admit. The same may be said of
the point of reunion. Otherwise the resistance of the inter-
mediate ways and of the entries must be determined and pro-
vided for, as may be seen in the example given below. The
aggregate resistance of the intermediate ways of the several
districts through which the air is circulated determines the
maximum number of splits which are possible.
Simple as is the theory, and satisfactory and economical
278 MANUAL OF MINING.
as is the plan when well developed, it is not easy of execu-
tion. The success of the plan involves an exact manipulation
and great skill in taking due precautions to balance the
various factors, to determine the equilibrium designed, and
to prevent one panel or district from receiving too brisk a
current at the expense of others. Hence, while it is eminently
desirable to apply this theoretical distribution, its difficulty
is recognized, and it has become the practice of the foreman
to approximate the desired conditions by making repeated
tests upon the quantity of air flowing in a given circuit, which,
if insufficient, is provided for by enlarging the inlet area for
the given district and watching its reaction upon the volumes
in the other dependent splits. In shallow workings, though
the mine may be extensive, the practice is an inexact one in
many cases. It may often be cheaper to sink a new shaft to
furnish separate ventilation to a district, than it would be t'o
undertake to furnish an elaborate system of splits.
Though it may not require a demonstration to show that
the subdivided splits of the current are productive of greater
economy in ventilating power, attention will be called to the
fact that the ventilating force in h.p., necessary to deliver a
volume, (2, against a mine resistance /, is measured by the
expression
h.p. = Op ~ 33000 = Qin -^ 6365.7.
The resistance which would be offered by the aggregate
of all the districts to the flow of the entire volume, Q, through
the whole length of the circuit is measured by /. Each frac-
tional volume, q, q , q" , etc., passing through only one branch
of the circuit would offer a resistance r, r', r" , etc., which is
very small compared with /. When the mine boss has
adjusted the regulator doors at the point of distribution by
altering the respective areas of inlets, the resistances in all
of the several circuits are equalized, the work performed in
each split is qr, q'r, q"r, etc., and the aggregate ventilating
power is their sum. As
^ + q' + q" + ■ ■ • = Q and r < p,
DISTRIBUTION OF THE AIR. 2Jg
the power required for the ventilation in branches will be less
than that for a single current Q, through the same passages.
The power required for 16,200 cu. ft. of air flowing in one
column would be capable of producing 70,884 cu. ft. of air in
five splits, 94,850 in ten splits, and nearly 100,000 cu. ft. in
fifteen splits.
Ex. 21. — A colliery is ventilated by a Guibal fan of 21' 3" diameter, making^
40 revolutions per minute. How many cubic feet will it jjroduce ? The air must
I'.iss itirrjuyh a main air-way 300 feet luni;, 6 X 12 feet, before being split up into
three separate air-ways, one being 12,000 feet long, 5X5 feet;" another 11,000
feet, of area 6X7 ieet\ while the third is 10,000 feet long and 5 X S feet in
section. Required also the water-gauge pressure, assuming the two shafts,
together to consume 0.226 lb. per square foot in friction.
16,380 cu. ft. and o.g inch.
The splits are all drawn from a common point of junction.
Theoretically, the fan produces a water-gauge pressure of o.go2 inch
(4.677 lbs.). Then the entire mine offers a resistance of 3.504 lbs. (0.676'
inch). The resistance of the main air-way is / = 0.0000000006279(2'. (?. the
quantity of air delivered, is divided up into three several sections, according to
their re istances. As p is the same for each, the quantities q may be known in
terms oi p to be
2171 y>, 3455 \/p, and 336S i//\
Now the resistance of the entire mine is equal to 3.504 lbs., plus that of
the main air-way, plus that of the splits, p. From this we know p = 3.504
— 0.0000000006279(8994 y/)', whence / becomes 3.333 and the resistance of
the main air-way 0.170 lb. Q then becomes 16,380 cubic feet, and the quanti-
ties received by the three splits are 3940, 6270, and 6110 cubic feet. (The dif-
ference in results arises from failing to carry out the decimals beyond two
places.)
Ex. 22. — An air-way 3000 feet long, S X 4 feet area, is carrying 20,000 cubic
feet. How many feet would be produced if the air was split into three currents,
\hepo-McT remaining.the same ? The sections are 3000 feet long and S X 4 feet
area; 3600 feet and 5X9; and 4800 ft. of 6 X 10 feet.
51,736 cu. ft. and 11.56 h.p.
The calculated power necessary to drive the quantity of air, Q, through the
three sections is equal to the sum of the three powers, pav, of each section.
The benefits that may be derived from splitting the air-
current are manifest by inspection of the following case :
Ex. 23. — A mine has two slope entries, 9 X 14 feet in cross-section and 100
feet long, and such internal resistances as would be equivalent to Sooo feet of a
typical air-way (see page 446) 5 X 10 feet in cross-section. What pressure and
power will be requisite to propel 16,200 cubic feet?
/ = 0.2619 and u ~ 4243 ft. -lbs., for the two entries, and
p = II. 19 and ti = 181,383 for the total.
28o MANUAL OF MINING.
Ex. 24. — Required the quantities of air that will circulate where there are
2, 3, 5, 10, and 15 equal splits, the pressure remaining the same as above.
After calculating the pressure/ for the one current as above, then proceed to
ascertain the pressure /' necessary to circulate 16,200 cu. ft. in the several
cases. These will be found 1.369, 0.405, 0.087.1, 0.0109, and 0.0032 lb. per
.■square foot, respectively; the areas, be it remembered, for the equal splits (see
ipage 447) are 100, 150, 250, 500, and 750 sq. ft. in the several cases, while the
Tubbing surfaces, hii, are the same (240,000 sq. ft.). The pressures are then
apportioned directly to 10,935 lbs., the mine friction of one current as above.
Whence, the pressures being as the squares of the volumes circulating, we obtain
33,409 cu. ft., 66,354 cu. ft., 91.692 cu. ft., 103,755 cu. ft., and 105,255 cu. ft.,
■and 373,887 ft.-lbs., 742,504 ft. -lbs., 1,026,030 ft.-lbs., 1,161,010 ft. -lbs., and
1,177,760 ft.-lbs. as the respective powers u.
Ex. 25. — If it be desired to know what quantities will circulate with the
same power u, as in Ex. 29, then we have but to apportion the volumes to the
cube-roots of the powers, ti, of Ex. 30.
Thus ^373.887 : 33,409 :: 1/181,383 : 26,252, the volume with 2 splits,
66,354:: 1/181,383 ; 41,479, " ■' " 3 "
91,692:: 1/181.383:51,461, "
1/742,504
^1,026,030 ;
|/i,i6i,ol'o: 103,755 :: {/i8i,383 : 55,S8i.
105,255 :: I/181.383 ; 56,419,
5
10
15
i/i, 177,760 :
E.x. 26. — When, however, the splits are not taken from a common point of
juncture, the procedure for ascertaining the mine resistances, and, subse-
quently, for balancing the delivery of air to the several sections, is not so simple.
As explained on page 203, the plan consists in determining the several resist-
ances and the powers necessary to overcome them. These are then added as
follows: Fig. 244 illustrates a case. D ie the downcast shaft, 846 feet deep.
Cl
i — N-
8 X 10 ft. in cross-section, delivering 56,000 cu. ft. per minute ; by force-fan,
27,750 cu. feet go to the left gangway, while the right gangway passes 28,250
cu. ft. of air. The water-gauge stands at finch (4.525 lbs.). Required the
volumes of air received by the splits A, B, C, and D.
The distances along the gangway at which the splits are taken are a, 460
feet from d ; l>, 960 ; and c, 1360 feet from d. Dimensions of gangway 6X12
feet.
The splits are E, receiving 5000 cubic feet through 100 feet of 6 X 12 ft.
gangway ; 60 ft. of 4 X 2 break-through ; and 60 feet of return air way 5 X 14
DISTRIBUTION OF THE AIR. 28l
> M. Eng.: The Effect of an
Obstruction in tlic Air-way of a Mine, T. L. Elwen, XLIV. 272,
O/iio m in. /our.: The Necessity of Making Break-throughs Even and
Uniform at tlie Mines, )as. W. Haughee, 1892, 19.
£.&= M. Jour.: Fire-doors for Mine Shafts, R. G. Brown, LVII. 321.
CHAPTER XV.
ILLUMINATION.
55. Use and consumption of candles, etc. ; Davy's discovery and inven-
tion ; description of the safety-lamp; remaiks regarding later forms,
Stephenson, Mueseler, Hepplevvite-Gray, and Marsaut. 56. Require-
ments of a safe lamp; modes of rendering them secure; candle-
power of the different types; electric illumination. References.
55. In an atmo.sphere containing ga.ses sufficiently diluted
to render it harmless illumination may be had by any form
of naked light. In all metal-mines candles are used, and
occasionally the torch and kerosene-lamp. In bituminous
mines known to be non-gaseous the latter is employed; but
in all mines which are at all likely to develop gases the
lamp-flame must be protected from direct contact with the
white or fire-damp.
Candles which are used in metal-mines are usually of
stearic acid, of which Proctor and Gamble's are the most
uniform and will best withstand the temperature of the
heated atmosphere. They are cheaper illuminators than
lamps in rooms and stopes, but not in haulage-ways. The
consumption averages three candles per man per shift. The
common tin lamp with the hinged lid on top and a hook and
spout on either side — from the spout the wicking projects and
is warmed — is a more brilliant -illuminator, and is also used
in coal-mines, giving a moderate light of about four candle-
power, with, however, the objection that it smokes.
Kerosene or petroleum is commonly emploj^ed as the fluid,
but its unsafely requires an admixtuie of a less volatile oil.
White lard, winter-strained oil is also much used, the con-
sumption being one-half gallon per month for each lamp. In
some mines rape-seed oil is used, though a mixture of equal
parts of seal-oil and petroleum seems best to meet the
292
ILLUMINATION. 293
requirements of a good illumination with a minimum of smoke.
In a mine using 2G0 duplex-wick lamps the annual expense
for oil, repairs, interest, etc., is S504.00. In selecting oil for
illuminating purposes, its behavior is tested not only from the
standpoint of its usefulness as an illuminant, but also that of
its ability to burn without smoke. When the oil burns and
the combustion is perfect, a blue non-luminous heating-flame
is produced; but when the conditions are such that the flame
is cooled during combustion or receives a deficiency of
o.xygen, the combustion is imperfect, and the portion of the
carbon in the oil is rendered incandescent, thus emittin<7 licht.
When the oil is very dense, the amount of incandescent car-
bon released becomes excessive, particularly in the presence
of a small amount of o.xygen, and soot is the result. The
ideal oil, therefore, should furnish a ma.ximum of light and a
minimum of soot, with sufficient combustion to produce
draught. A simple test and a decisive one may easily be made
for the fitness of oil for use in the miner's lamp by burning it,
under the ordinary conditions, in a common house lamp with
a short chimney. The mi.xtures, which are often used, of
mineral oil with animal and vegetable oil are always objec-
tionable because of the almost unendurable odor, which itself
is detrimental to good air. There is little saving in their
employment, and they are worse than is either oil unadul-
terated. The very volatile oils and spirits, like benzine, burn
with a clear uniform flame, show an easily perceptible cap in
the presence of gas, and are usually very sensitive, being also
free from danger in a well-constructed lamp, even in the
hands of an unskilled miner.
In mines working under the long-wall system with an
ample current naked light may be used, but should be
restricted to narrow \vorks, and in mines working by the pillar
and stall, to the rooms ventilated by splits, and not for
robbing pillars.
A great deal of ingenuity has been expended in the
endeavor to invent a safer means of illuminating workings
than that offered by the naked flame. In 1815 Davy dis-
294
MANUAL OF MIjVIXG.
covered that a sheet of iron-wire gauze was so good an
absorbent of heat that the flame in contact with it could not
readily pass through. Further experiments indicated that
for mining purposes a mesh of 784 holes to the square inch
was the safest, and was therefore adopted as the standard.
A cylinder of this mesh, surrounding the light, surmounting
an oil-lamp and capped by a perforated top, is the form,
which has been little changed since Davy's time (Fig. 108).
After the lamp is filled with oil and lighted, it is locked, to
bar the miner against access to the f^ame, the wick of which
is trimmed by a wire passing
up through a close-fitting
tube from the bottom. The
combustion is supported by
air penetrating the gauze at
all sides.
Sir Humphrey Davy thus
describes his invention : ' ' The
principle of my lamp is that
the flame by being supplied
with only a limited quantity
of air should produce such a
quantity of azotic or carbonic
acid gas as to prevent the
explosion of fire-damp, and
^"^- "°^- '^"=- ■°''- which, from the nature of its
operations, should be rendered unable to communicate any
explosion to the outer air."
The lamp has done and continues to do great service; but
it has two defects. The first is the liability of the gauze to
become red-hot, and allow the flame to pass through to the
inflammable mixture outside. The second objection is its
low illuminating power. The open spaces occupy only one
fourth of the area of the gauze, through which the light
escapes horizontally; still less light gets out at the top, to
illumine the roof. Miners require light thrown in every
direction, especially upward ; and in a certain investigation.
ILL UMINA TJOiV. 2g 5
\vliile giving evidence, confessed that they would ratlicr
unmask the flame and risl< explosion, than not to watch and
see distinctly the roof, the ever-threatening danger of which
can scarcely be denied. These defects have been partially
remedied in the subsequent patterns by the use of glass, the
only impermeable, strong, though brittle, transparent sub-
stance.
The Clanny is the first alteration of the Davy, a lower
portion of the wire cloth of which, if replaced by a short
cylinder of glass, gives somewhat better illumination (Fig.
109). The simple expedient of enclosing it or the Davy in a
tin can or shield is also quite an impro\'ement.
Stephenson's, almost as popular in this country as those
above, has a long cylinder of glass surrounded by a wire
gauze, and bonneted above by perforated copper. The feed
is also through the gauze, going underneath and into the
cylinder to the flame, thence out at the top, as usual. This
plan keeps both c)dinder and gauze cool, and its relative
security rests essentially on the regularity of the draught, for
if the inside air becomes overheated the light goes out; so it
must be suspended properly. This is an English favorite.
The Marsaut is an improvement upon this form, and
stands a fair amount of tilting safely. With care, its glass
cylinder will last three years before breaking. The Marsaut
lamp in many mines abroad is regarded as the most suitable
one for the working miner, its construction being simple and
strong, and as an indicator of gas it is reliable, furnishing also
a good light. Of 370 in use, the average consumption of
rape-seed oil was 2 gallons per year. This lamp was brought
very prominently before the public by the Accidents in Mines
Commission. A great difficulty is experienced in relighting
it, and from the winding path pursued b\' the feed air proper
circulation does not take place until the lamp gets hot.
The Mueseler, a IJelgian lamp, is like Dr. Clanny's,
having in addition a conical chimney centrally above the
flame. It is highly recommended in Europe, but must be
carefully handled. It does not burn well in " dampy " or
vJ-.
296 MANUAL OF MINING.
slow currents. The bonneted Mueseler, an English improve-
ment, is receiving the highest encomium for use in fiery mines
and high velocity.
The Hepplewite-Gray lamp admits air at the top, down
four tubes, and through an annular chamber above the oil
vessel. The only gauze employed is that covering the outlet
and annular inner chamber. A serious difficulty with it is its
liability to be extinguished when suddenly lowered. It
undoubtedly gives more useful illumination than anj' other
lamp, and as an indicator of gas undoubtedly ranks superior
to all others — except, possibly, the Pieler or Wolf varieties.
All other forms with the inlet above the glass will miss, say,
four inches of gas lying immediately against the roof, except
when they are tilted very much, and then there is great
danger of their going out. Many lamps are now constructed
to take air, if desirable, from the top, like the Gray, and thus
also to detect thin layers of gas; but even then they will not
do it so rapidly. It is possible to put some modern lamps
into gas and take them out again without any indication
being given — if the test is conducted hurriedly. This is
quite impossible with the Gray, as the flame immediately
"spires" up. Owing also to the large amount of useful light
given by it and the way this is directed on the roof, in addi-
tion to its delicate indications of gas, this lamp is preferred
to all others for use by deputies, firemen, timberers, and fire-
bosses.
The Dick patent port-hole lamp compels all the air enter-
ing the lamp to go immediately to tlie flame, thus losing no
air, and is capable of burning in a stagnant atmosphere. The
air entering the lamp above the case passes through the
gauze, thence descends to the flame, while the products of
combustion arise inside the lamp, to be emitted through cir-
cular holes at the top of the bonnet. The bonnet is made of
a seamless steel tube, and is light and strong.
The Wolf benzine safety-lamp is an emphatic departure
from the varieties above described, in that, first, it burns
benzine or naphtha; second, it contains a patent self-igniter
ILLUMliXATlON-. 297
capable of relighting the lamp fifty times without opening;
and, third, it contains a locking device which it is impossible to
open except by the use of an exceedingly powerful magnet.
This lamp, because of the sensitiveness of its illumination, is
a delicate detector of gas, and has met with very ready
acceptance throughout coal-mining districts, there being possi-
bly 80,000 in use in Germany. Of 18,300 lamps in one mining
district in Great Biitain, over lO.ooo are either Marsaut,
Mueseler, or bonneted Clanny.
Notwitlistanding the various modifications, there is yet no
really safe lamp — one that cannot ignite in an explosive mix-
ture outside of it. Generally, the elongated appearance of
the flame gives warning of danger to the man carrying it into
a fiery atmosphere; and it would be the better part of valor
to smother the light or to withdraw from the spot before the
heating of the gauze begins.
56. The "safety" lamp must be capable of resisting
explosive currents of highest velocity attained underground — -
that the air-current shall not be able to blow through the gauze
into the lamp or to force the flame against the gauze. This
permeability is determined by the mesh, and there is a limit-
ing degree of safe coarseness and of speed of current. The
Hepplewite-Gray and the bonneted Mutselcr have the best
resistance to explosive currents of higli velocity, and the
South Side Committee report the following relative speeds at
which the respective lamps and the air-current can safely
pass: Davy, 360 feet per minute; Clanny, Goo feet; Stephen-
son, 780; Mueseler, naked, 1200; Mueseler, bonneted, 2400;
Marsaut, in a can, 2440 ; and the Davy, in a shield, 2400.
The North of England Institute of M. IL gives the safe
velocities at 720, 540, and the others higher. The Ikitish
lioyal Commissioners of Accidents approved the Gray,
Marsaut, and the bonneted varieties as safe at high speeds.
The common Davy or Geordie lamps are unreliable.
In order to be safe in the highest velocity of air-currents
witb.in a given mine, the flame must be enclosed not only in
a wire gauze, but also in a more or less impermeable hood or
■yfi-^-
298 MAAWAL OF MINING.
bonnet, while the inlet area for the feed-air must be reduced
to the smallest allowable dimensions. Many lamps now exist
which appear to resist, in a highly explosive atmosphere,
current velocities up to 3000 feet per minute for a period of
several minutes; and the four lamps which were brought to
the attention of the Mines Accident Commission, which
received special attention for their security, illuminating
power, and simplicity of construction, were the H.-Gray,
Marsaut, bonneted Mueseler, and Thomas's modification of
the bonneted Clanny.
The bonnet screens the gauze cylinder from the effects of
draughts that blow the flame through the meshes and set up
a fiery heat by the excessive air and gas that enter above the
flame of the wick. It limits the supply of air to that required
for the oil flame only. Such bonneted lamps, whose flames
are protected from the direct effects of the strong ventilating
current, may be used with safety for illumination in mines
producing fire-damp. Even in dry, dusty mines also develop-
ing fire-damp some of these lamps are safe, though not all;
for many well-authenticated cases of failure are recorded
where the dust has proven fine enough to pass through the
gauze meshes, to be reduced to the state of incandescence in
the inner chamber.
Of the forty-one explosions which occurred in a certain
district during 1896, in four cases the immediate cause of
ignition was referred to a naked light or to a deterioration of
the safety-lamp; in twenty-five, to the passing of the safetj'-
lamp flame, in consequence of the gai-ize heating through a
careless movement, too high a speed, or "falls in." The
remaining twelve were from shot, fire, or other undetermined
causes.
The importance of locking the lamp so that its flame can-
not be exposed to the gas is manifest, as there are many
temptations to the miner to open it in order to better illumine
the roof or to light a pipe. Either practice is reprehensible.
All manner of permutation-locks and magnetized plates are
offered on the market, besides the lead-plug seal with which
ILLUAriNATION. 2g(j
the lamp is riveted after each filling. The latter is giving
satisfaction in S. Wales. The magnetic locking device of the
Wolf lamp has proven effective to resist all efforts of the miner
to open it. Other lamps are so constructed as to extinguish the
flame when the oil vessel is separated from the gauze cylinder.
The illumination from an)' of these lamps is very feeble —
best horizontally, but less in any other direction. Of all the
lamps the Gray sends the best light upward. The candle-
power, horizontally, of the Roberts is highest — about i8, and
of the Clanny the lowest — nearly 6. On this account a lamp
must be able to be held tilted without extinguishment, and be
unaffected by violent oscillations. The conditions dictated by
safety circumscribe the lines of attempted improvement in
the degree of illumination. The brass lamp is found to be
70 per cent as bright as the iron lamp of the same pattern
preferred by the Germans. PlTotometricall_\- speaking, seal-oil
is better than rape-seed, and a broad, flat wick than a round
one. The insufficiency of the light of a safct\'-lamp, combined
with the difficult and trj'ing conditions of the bonneted forms,
is proving injurious to the e)'esight of miners, which serious
evil is growing. Photophobia is rare where candles are used,
or where the lamp is hung behind the miner.
At Zwickau, Saxony, a novel and bold plan is in use, owing
to the difficulties with all safet}' lamps ; an innumerable quan-
tity of naked lights are burned constantly, which ignite the gas
as fast as it reaches the candles. No explosions have been
recorded.
Whatever the means of illumination, the lamp must be
self contained, be strong, [)ortable and not heavy, require little
attention from the miner during twelve hours of sustained light,
and be capable of placing in an)' position, besides giving per-
fect insulation from the fiery gas. In an incandescent lamp,
wire-bound, and with flexible connection, electricity fulfils
many of these requirements, besides requiring no oxygen, and
it seems reasonable to expect it to supersede the present form
of lamp. Its success in metal mines makes the proposition for
collieries not so absurd as would at first sight appear. Large
■ 30O MANUAL OF MINING.
chambers would thus be safel}' and so thorouglily lighted
as to render ever}' part of the roof visible, affording greater
security to the hewer. A greater number of lights would be
required than of oil, as the former cannot be continually car-
ried about beyond the limit of the flexible connection. Again,
along the entire galleries numerous lights would have to be
placed, except in the haulage-ways, where lamps in the hats
may be permitted. Though the electric system is not suffi-
ciently perfected, many mines employing this force for other
purposes find it better and not much dearer than oil. The
cost of a plant for lOO lamps, exclusive of the generating
machinery, is $500; and for coal, renewals, interest, etc., the
annual expenses are $518. One h. p. will run ten 16 c. p. lamps
at 75 to 150 feet apart. The life of a lamp (60 cents) is fully
100 shifts. A serious detriment is the fracture of, or the in-
jury to, the wires. A portable, self-contained secondary battery
lamp may obviate this, but it is both heavy and wasteful of
power.
Lamps are not safe unless kept in thorough repair, and in=
fractions of rules regarding their use severely punished. The
gauze should be steeped in a hot alkaline solution, to free it
of soot, etc. Lamps burning benzine are not clogged with
carbonaceous deposit as are those burning oil. There is
To avoid waste, manufacturers furnish automatic fillers,
holding just enough for a lamp. Lamps should be occa-
sionally tested for leakage and other sources of danger.
The following references are cited:
Anier. Inst. M. E.: The Wolf Safety-lamp, Eugene B.Wilson ,XIII.
129; The Wolf Benzine-burning Safety-lamp, E. }. Schmitz, XIV. 410;
Hydrogen-oil Safety-lamp, Prof. F. Clowes, XXII. 606.
Coll. Eiit;-.: The Diffusion of the Light of a Safety-lamp, XVI. 1S7.
E. &^ Rl. Joiir.: Electric Lamps in •Coal Mines, LIX. 316; Safetv-
lamp, Gas-testing, LVII. 149.
Fed. Inst. M. E.: Electric Mining and other Portable Lamps, Anon.,
II. ; Notes on Safety-lumps, Herbert W. Hughes, F.G.S., II.
Kep. of Mint- Inspectors : Illuminating Oils in Mines, R. Haseltine,
Oliio, 1895, 46.
Coll. Guard.: Remarks on Use of Lamps, Dr. C. Le Neve Foster, Dec.
1896, 1 1 17; Bonneted Lamps, lames Ashworth, Sept. 1S95, 542; The
ILLUMliXATlON. 3OI
nahlinaiin Safety-ramp, Hcrr R. Crcmer. Oct. 1895, yot ; Notes on
Underground Lighting by Electricity, John Daw, 1K97, 272; Iin|)r(jved
Miner's Safety-lamp, A. T. M. Johnson, LXXII. S71 ; Wolf's Self-
ligining Safety-lamp, Karl Wolf, LXXl. 936.
Coll. Mgr.: Electric Lighting in iS'lines, Mr. Brown, 1894, 85 ; A. Reid,
1894, 83; Light as an Au.xiliary to Mining Preparations, James Laverick,
April 1895,63; Safety-lamps, April 1893,73; The Safety-lamp for Light-
ing and Testing, Prof. Clowes, April 1893, 66.
Man. Geo. Soc: On the Pieler Safety Lam|), C. Le Neve Foster
XVIL 252; On the Wolf Safety-lamp and the Contrivance for Relight-
ing it, C. Le Neve Foster, XVIL 280; On a New Lead-rivet Mould, H.
Bramall, XIX. 364.
///. Mill. Inst.: Miner's Sunshine, John P. Cuniming, III. loi.
CHAPTER XVI.
HYGIENIC CONDITIONS.
57. Laws upon ingress and egress; accidents in mines; ladders, tlieir
arrangement and cost; loss of time and energy; use of cages for
men ; conclusions of the Cornwall Society. 58. INIovable ladders or
man-engines, single or double ; utilization of the pump-rods for the
purpose ; comparison of the safety of the man-engines with other
means ; cost of the machinery and plant. 59. Accident laws for the
protection of life and limb ; arc equally effective for the security of
the mine; statistics; accident-rate decreasing ; tables; lessons drawn
from their inspection; causes and prevention of accidents; fall of
roof; lack of timbers; explosions; premature blasts; necessity for a
rigorous enforcement of the rules and laws. 60. General remarks
concerning fires in mines, their causes, prevention, and treatment;
entering old mines ; aerophores. References.
57. For purposes of ingress and egress, mines tire provided
with ladders or man-engines, where tlie cage or bucket is not
used. Tlie statutes of many States present varied ideas, the-
ories, and requirements for tlie accomntodation of the men.
Some require tlie maintenance of substantial ladders in a sep-
arate compartment, as the sole means to be used by the men
for entry and exit. In other States operators are relieved of
the necessity of keeping up a ladder-way, if safety carriages
are employed. The laws of many States forbid the use of
buckets by the miners, while the general tendency in all re-
gions is to insist upon two well-equipped escapement ways.
If the angle of entry is below 30°, no special provision is
necessary. The mud-sills of the timbering break the descent
into sufficiently convenient steps. Steeper than this, and up
to about 60°, some variety of treads is necessary. When the
pitch exceeds this, the compartment must be provided with
ladders, isolated from the hoistway. They should be inclined,
302
HYGIENIC COiVDir/OiVS. 303
uniform in direction, at an angle of not less than lo'' from the
vertical, to diminish the fatigue of climbing, and enable the
men to carry tools with them. At equal distances down the
ladder-way (20 to 40 feet down a vertical shaft, and at greater
distances on an incline), platforms are built of 2 X 6 beams and
2-inch planks, closing it, except for a man-hole, at the foot-
wall end. The ladders extend up through the man-hole, and
are fastened by staples or toe-nailed to the shaft-timbers, and
rest on the far side of the plats. They are made of 2 X 6
standards, 18 inches apart, with iron or wooden rounds or
rectangular slats 12 inches apart. The last-named are cheaper,
last longer, and give better toe hold than wooden rounds,
which, in turn, arc easier to use than the more durable iron.
Wooden ladders cost from 6 to 10 cents per running foot ;
iron, 20 cents.
Though used in Europe for 1200 to 1500 feet depth, and in
this country in deep mines, they are certainly not advisable.
According to the Cornwall Societ)', the use of ladders deranges
the respiration, and shortens life by ten years. The miners
reach the workings more or less exhausted, and the operators
have lost the benefit of a projjortionate amount of energy.
Unquestionably, an element of success worthy of attention by
mine managers — a pecuniar)' as much as a humanitarian cjues-
tion — is the proper treatment of and the conveniences for the
men, who unconsciously reciprocate in an equivalent of work.
Besides, time is lost. It takes 15 minutes to go down 300 feet,
and the ascent is twice as slow. A shift of forty men, follow-
ing one another at intervals of 8 feet, entails a loss to the
company of 31 minutes each shift. With buckets and cages
the loss is not so great ; eight men at a time, lowered 1200
feet, consume 40 minutes for every shift of 100 men. An ad-
ditional loss occurs at tally-time from the reduction of the
hoisting capacit)', which, with the impatience of the men, leads
to the crowding of the cage ; but in most States the limiting
number of men permitted on the cage is named. A serious
form of accident, peculiar to deep mines like the Comstock, is
the fainting and falling, which occurs when the heated miner.
304
MANUAL OF MINING.
while being hoisted, comes into contact with the air near the
surface. There is no safeguard against it, and owing to its
frequency men never go up alone.
58. Movable ladders or man-engines, invented by D'Orrell,
of Clausthal, were instant!)^ adopted as acceptable substitutes
to the methods previously used, and now are very popular
in deep mines. Mr. Lorn, who introduced the engine in
Cornwall, was handsomely rewarded by the Royal Polytechnic
Society, which declared it a "great boon to miners." Its in-
troduction involved the addition of some machinery, but it
was easy to operate.
Two rods, of decreasing cross-section from top down, re-
ceive at the surface an oscillatory motion
from balanced bobs, operated by an engine
having a fly-wheel and other regulators.
The dimensions of each rod at any point
must be such that it will liave the requisite
tensile strength to support the weight of
the part below it, loaded with men. They
play between roller-guides 50 feet apart,
and are provided with wings and catches,
after the manner of the Cornish pump-rods,
which may, in fact, be utilized as " Fahr-
kunst " rods without much extra power.
Each rod has a small platform. Fig. 109,
about 12" X 12" or 18" at every 12 feet
— double the length of the stroke. A
handle four feet above the platform gives
support to the miner, who is carried up 6 feet
on one rod, which brings him opposite a
platform on the companion rod ; upon this
_, he steps, to be lifted 6 feet more, to meet a
plat on the first rod, which has been coming
down to receive him. A miner stepping
from one to the other is carried up or down
at a rate of from 48 to 96 feet per minute
(each rod makes 4 to 8 double strokes, delivering one man each
IIYGIKXIC COXDITIONS. SO?
time, those at the Calumet and Hecla make five strokes). As
there is no hmit to the depth at which these may be carried,
and as they are capable of working alike in slopes as in shafts,
it is not surprising that they " take" so well. They replace
bolsters, and require little additional power or space. Tools
and supplies cannot be carried by the miner, but may be de-
livered by the cage or bucket.
A single rod is also used, its companion being replaced
by stationary platforms attached, 6 feet apart, to the shaft
timbers. Upon these the ascending men wait during the
down stroke of the rod. The single-acting man-engine re-
quires chains and counterpoises at intervals to balance it, and
to prevent the shock incurred at the end of the strolce.
From the fact that a misstep would be fatal, it would seem
as though man-engines were extra-hazardous, yet the accident
record does not confirm this fear. Some confusion is caused
by a man missing his plat and riding on, to the annoyance of
those following him ; but this is of rare occurrence unless his
light goes out, for there is a halt of several seconds at each
change of motion. Out of an average of 100,000 men em-
ployed for ten years (in Prussia), onl)' 57 were injured on the
man-engines; in Cornwall, 17. This is more than compensated
for by the increased length of life of the miners using them.
The cost of machinery, etc., for a 1200-foot man-engine is
$18,000, upon which interest and depreciation may be figured
at $2500, — amounting to 10 cents per man daily, on a gang of
100 men. The running expenses at the Dolcoath mine are 4
cents per man, 2400 feet.
59, We now arrive at the consideration of a theme which,
sad as it is, should suggest the lines of improvement. Deplore
as we may the immolation attendant upon mining, tlicrc
seems no way, by legislation, threats, or punishment, of ini-
pressing the necessity of vigilance upon the miners, who by
long inurement to peril that is imminent have become oblivi-
ous of the unavoidable sources of danger.
The statutes make stringent requirements of the operators
and of the employees, enforce frequent thorough inspection.
3o6
MANUAL OF MINING.
by competent men, impose fines and penalties for negligence
or non-compliance, and our appliances are useful, durable, and
modern ; yet the benefits that should accrue are not realized —
the death-rate continues deplorably high. The percentage of
accidents in steep vein-mines is less than that of iron mines,
and only half that in coal-mines, where 3 out of every 1000
employees are injured annually. Bituminous collieries are
more dangerous than anthracite or lignite mines. The rate
has been decreasing somewhat, as might be expected, though
the increased depth of working tends to make mining more
hazardous ; and, assuming equal conscientious announcements
by the authorities reporting the casualties, it will be found
that the safety of life in our mines bears satisfactor}' compar-
ison with that in European mines. Generally, the accident
statistics are compared with the output tonnage, and it maybe
said that for every 200,000 tons of coal mined one life is sacri-
ficed and two men injured. That this proportion is diminish-
ing is patent to any one inspecting the reports of inspectors.
Though it is difficult to get a trustworthy comparison of the
number and class of accidents, the following table is given,
showing in percentage the fatalities and casualties. The mis-
cellaneous accidents vary from 2 to 27 per cent of the total
number.
Pennsylvania, 1889 :
Anthracite
Bituminous
Illinois, 5 years
Ohio, 1874
" i88g
Iowa. 1889
Missouri, 1889
Nova Scotia, 5 years.
Comstock
Missouri, zinc
Colorado, ore
Illinois, l88g
Italy, 1889
Falls of
Roof
and
Coal,
/*
45
6^
63
61
76
64
50
62
In
Haulage
Ways,
Fire-
damp.
64', 18
12I
45I
60
67 13
61 24
13' 6
25
Powder,
Tons per
Accident.
34,Si7
102,414
66,200
4,844
128,322
52,400
111,173
167,083
52,140
8,376
19,460
42,988
$42,400
Tons per
Life Lost.
-Q
105,764
397,612
215,5491
108,9191
330,529'
98,620
222,347
238,697
238,450
$152,993
342
585
716
412
6ig
321
514
618
539
752
* Columns headed /are fatal accidents ; those headed s, serious.
HYGIENIC CONDITIONS.
PERCENTAGE OF FATALITIES,
307
Enijland, 1851
18S8
Prussia, 1852.
1889.
France, 1853.
18S9.
Belgium, 1S61
18S8
Falls.
34-3
53-0
50.0
40.0
40.0
30.0
36.7
35-3
Lad-
ders.
Fire-
damp.
Pow
der
In
Shafts
'•7
30.0
21.2
2.3
5-4
13-5
4
8.5
20.4
2.0
12.8
=;
10.
20. 1
3
6
21.4
1.5
28.6
I
14-3
2. 1
10 3
3
I
13 4
1-5
16.0
2
8
8.2
Tons per
Life Lost.
63,562
194,430
83,051
109,528
37,346
i'7,i05
51,840
106,110
Em-
ployees
per Death.
222
600
600
365
260
53S
422
571
But the talcs which these fij;uics tell must be noted. First,
that notwithstanding" the frequent holocausts, with the reports
of which we arc shocked, the loss of life by explosions and fire
is not by any means as great as by the more numerous unpub-
lished accidents to individuals resulting from the caving of roof
b\' reason of insufficient timbering. Fully one third of the
deaths are frcjm this cause, — and the percentage was the same in
the'50's as now — and neither the operators nor the bosses are re-
sponsible always for them, as subsequent investigation reveals.
The crushing of men b)' the fall of coal upon them is an equally
common accident. Many casualties are caused by the indiffer-
ent miner, anxious to make a big turn-in, neglecting to support
the roof of coal with the timbers right at hand ; in fact, I
have seen instances where a crush had caught victims who were
compelled to crawl over a supply of props in order to reach
their work. It is an incontestable fact that the miner will take
too many risks, and an accident ensues solel)' from his own
carelessness. It w ould be unjust to attribute all accidents to
«'ilful neglect, for mining is precarious ; but surely many calam-
ities might be avoided if the miner would exercise precau-
tion. It is not sufficient that he is the victim of his own wil-
fulness, — for the evasion of the law carries its own penalt\', —
but he endangers the lives of his co-laborers, and the property
of the employers who have invested heavily in measures for his
protection. The sudden dislodgment of the roof or sides of a
breast or stope, or the unnoticed yielding of the pillars, is due
3o8 MANUAL OF MINING.
The various grades of underground accidents which occur
in collieries and in metal-mines bear nearly the same ratio to
one another in the two classes of workings, though the aggre-
gate number of accidents and fatalities may not be, in the two
cases, the same. A comparison of the lists of fatalities of tlie
earlier periods of mining in the current century with the lists
which are published annually at the present time demon-
strates the great improvement which has been effected in
underground conditions; many of the evils surrounding a
miner's life in the early days have been removed, while the
consequences of the other sources which remain have been
lessened to an extent that makes the occupation of a collier
more than tolerable ; indeed it is no longer the most hazardous.
That coal-mines are more hazardous than metal-mines is
commonly but erroneously belie\'ed. For, while the number of
injuries or fatalities is small in the latter, yet it must be borne
in mind that the number of employees is also smaller, thus
making the proportionate number of injuries from accidents
in coal-mines lower than in metalliferous mines. The latter
class of mines are under less rigorous inspection than are those
of the former, in which the danger from explosions of fire-damp
has been so far reduced as to ahnost eliminate this cause.
The sudden dislodgment of the roof or sides of a breast
or stope, or the unnoticed yielding of the pillars, is due to so
many causes, that it is impossible to prescribe rules for its
prevention. Horses, sigillaria, balls of ironstone, rock creviced
naturally or by excessive blasting, are threatening conditions
that demand a liberal supply of precautionary timbers or filling
placed before the movement begins ; otherwise, once begun,
no amount of subsequent support will save it : the ensuing
damage is out of all comparison with the insignificant item of
props judiciously used. Moreover, without a better system of
illumination of the underground workings the miner cannot
discern the condition of the overhanging rock, and props, to
be opportune, must be placed at once. The substitutes of iron,
steel, and masonry for wood must conduce to a greater safety,
as also the increased facilities for the more expeditious removal
of mineral.
HYGIENIC CONDll IONS. 3O9
Falls of roof are responsible for the great inajority of lives
lost underground, whether in coal or metal mines; and, while
this class of accidents is most frequent in thick seams and
steep seams, nevertheless the occurrence of weak spots and
" bell-moulds," suddenly liberating masses of stone without
warning, are equally frequent. The fall of coal from the side,
during the long-wall or pillar and stall working, also raises the
mortality in coal-mines, the remedy for this, as for the others
just mentioned, being a plentiful supply of tiinbering set with
their joints at right angles to the lines of cleavage, and limita-
tions in the size of the excavation. If the miner would be
more watchful and promptly set the timbers this grade of
accident would diminish. It is always the so-called safe roof
of overhanging rock which causes the trouble. Men, who
would never think of opening a safety-lamp will continue to
labor under a roof which, they think, will stand till night.
The sole remedy, in the opinion of the author, lies in the
issuance of an order for the unconditional dismissal of any
employee wlio fails to prop loose ruck, and a rigid, instan-
taneous enforcement when the discovery is made.
A brief study of the table of deaths in the mines of tiie
United Kingdom during the history of coal-mining verifies
the conclusion that is quoted of our Pennsylvania Mine
Inspector, that accidents from this cause and " from cars are
regular and uniform items in the death and injury lists,
whereas those resulting from blasting or gas-explosions are
sporadic and irregular."
Arranged by decades, a similar table of accidents for the
anthracite fields of Pennsylvania would give equal results,
though to attempt the comparison of accidents with other
countries is difficult, because of a difference in statutory
requirements, the lack of uniformity in the definition of
" fatality," and the imperfect classification of accidents.
Mine inspectors give preference to the place of occurrence
rather than to the cause of accident in their classifications and
reports.
3IC
MANUAL OF MINING.
AVERAGE NUMBER OF ACCIDENTS IN MINES OF THE UNITED
KINGDOM IN SEMI-DECADES.
Numbe
of Em-
Average Annual Fatalities.
Total.
Death - rate per
1000 Persons, all
plo>
Causes.
_6
0.
>
S.
i2
li
u
>
>
u
rt tn
m
<
Ix.
CO
231
i
CQ
<
ra
<
1851-55
. 182.427
47,047
368
235
lOI
Q37
47
5.149
1.012
1856-60
. 208,763
53,832
385
187
257
135
964
53
4.628
0.994
1861-65
■ 237,779
61,314
406
159
146
IS6
SgS
68
3-791
1. 1 05
1866-70
• 269,813
69,574
426
142
306
1 96
1 07 1
87
3-995
1.256
1872-75
• 399.397
111,584
470
174
195
225
1066
99
2-736
899
IS76-80
. 424.586
117,876
480
134
341
190
1 147
100
2.709
0.847
1881-85
443,502
116,688
491
116
181
236
1025
99
2.312
0.848
I S 86-90
• 477.633
126,654
482
93
152
247
975
117
2.042
0.913
1891-95
• 571,463
150.804
457
III
141
270
979
123
1.705
0.822
Accidents in and about the traffic-ways are being reduced
by the use of safety appliances, previously referred to ; by gates
and doors at the mouth of shaft and level ; by a small drift
cut in the hanging-wall, for miners to pass around instead of
across the shaft ; by whitewashed safety niches at every 100
feet in a gangway ; by care in signalling ; and by having a space
2 feet wide between the "loaded " cars and the side of the
heading.
The effects of sudden changes of temperature experienced
by those coming from a hot portion of the workings to the
surface may be remedied by prudence on the part of the
miner, and by railings around the cages. The new Pennsyl-
vania law requires hand-rails on cages. Dr. G. C. Swallow,
Mine Inspector of Montana, suggests an excellent idea to pre-
vent the mutilation of men riding on the cage. A coiled wire
screen, which may be drawn down at the sides of the cage, is
fastened below, and prevents the contact of men with the tim-
bers. Except in fainting, men caught between cage and tim-
bers have only themselves to blame for accidents on cages.
Miscellaneous accidents in shafts arise from materials fall-
ing therein, or from over-winding, or the breaking of hoist
rope or chain. The only remedy for this is the maintenance
HYGIENIC CONDITIONS. 3II
of fences at the surface, and a careful daily inspection of
ropes, with a simple and unmistakable system of signals.
Accidents caused by premature blasts are more frequently
the result of carelessness, though many unaccountable explo-
sions have occurred. Electric firing of cartridges, the pro-
hibition of loose powder, and the avoidance of firing in
collieries while much fine dust is afloat materially diminish the
casualties.
After all, neither legislation nor appliances will avail if the
men do not have an ever-present realization of impending
danger, and a corresponding caution. Doubtless many of the
charges of carelessness are unjust, for only at the critical mo-
ment may have come an instant of abscntmindedncss, when the
fatal act was committed. The only hope is for a change in
human nature, for until men willingly obey the laws, and on
occasion deny themselves of some slight fancy, accidents can-
not entirely be prevented. All precautionary measures should
be announced, rigorously enforced, and the offender, in no
matter how slight a particular or what the plea, discharged. It
is nnt tin: visitors who are the victims : it is the old hands, in
the pockets of whom pipes and matches arc presumptixx- evi-
dence. These, with fuse, tobacco, etc., should be contraband
goods, and subject the miner introducing them to r.iie.
The great mortality in metal-mines, as compared with
coal-mines, is unquestionably from carelessness when we find
on the list, among the common causes of accidents, "thawing
frozen dynamite," " igniting too many blasts at one time,"
" drilling into unexploded cartridges," " using iron tamping-
bars," and " tampering with the metallic caps."
Before a recent Austrian Government Mining Commission
(1897) evidence was given that, of the accidents that have
occurred there 60 per cent were caused by the victims or
their mates as the result of carelessness or incompetence; 30
per cent were caused by circumstances over which the men
only had control; and the remaining 10 per cent were of the
non -preventive class. This general deduction would likely be
verified by those cognizant of the facts in other districts.
312 MANUAL OF MINING.
But as to the character of accidents which are to be termed
preventable we are not assured. Perhaps only those not
anticipated are non-preventive.
The causes enumerated thus far involve usually only the
direct instrument of the accident, or the mines in the imme-
diate vicinity of the accident. But there are causes more or
less preventable which, when casualty does occur, involve a
multitude of lives; chief among them may be enumerated as
follows :
I. In the opening out of a seam beyond a fault. This fre-
quently gives rise to a slip in the ground, if soft, and always
the evolution of a large bulk of gases. 2. The working of a
piece of coal in advance of the face, which like\\'ise delivers a
heavy outpour of gas in the shape of blou'ers that are liable
to be converted into dense accumulations at any time.
3. Walling in gases. It was a very general custom to wall in
the gob in many collieries, but the result has been that with
a sudden and extreme change from high to low barometer a
great volume of gas was released into the mine. Moreover,
as air could not be entirely isolated from the chamber, it was
impossible to prevent the formation of a mixture more or less
explosive. All such works were performed at great risk , and
the present system, therefore, is to leave all those places open,
keeping them constantly clear of all accumulation. 4. Shot-
firing in main intakes. The danger here arises from the
quantity of dry coal-dust usually produced not only by the
blasting, but also pulverized and distributed by the' cars. A
thorough wetting of the surrounding surface will afford the
necessary protection before firing each shot, unless flameless
explosives with the use of electricity be used. 5. The firing
of goaves. In these spaces the coal-dust, slack, gas, and
pyrites are stored; and \\\\\\ the inevitable spontaneous com-
bustion that follows, a pressure ensues with greater or less
" breathing," by which much gas is exuded through the
fissures in the bottom, at the roof, or from cracks in the side
walls. When this source of gas is not recognized, the danger
ensues from the impoverishment of the air, even if the tern-
HYGIENIC COiVD/riONS. 313
perature of the mass within the goaves does not reacii that of
the point of ignition of the material contained therein.
Undoubtedly the goaves should either be imperviously
walled up or entirelv removed. 6. Approaching waler. The
nearest distance that it is safe to work towards water varies
according to the thickness and the nature of the seam, the
width driven, the width of the place containing water, the
difference in level of the two places, and the pressure and
volume of the confined water. Defects in the shaft-tubbing,
the breaking of the strata under a reservoir and above the
mine, and the cutting into the old workings filled with water,
cause man)' accidents under the general name ijf inundations.
The irruptions from abandoned works arc the result of a
breach of rules regarding reservoirs and bore-holes, or are due
to old inaccurate plans. A remedy for this is a due precau-
tion in the establishment of barrier-pillars. Any seepage or
appearance of " bleeding " at the face should be traced.
Spontaneous combustion can be obviated only b\- an active
air-current, or b)- change in the method of mining to one
involving complete removal of the coal and a substitution of
clean ^vaste. Gob-fires and accidents therefrom are eliminated
by removing the aggravating source, oxidation.
A sudden disengagement of gas into abandoned workings
not copiously ventilated, or into those in which the air is stag-
nant, may lead to fire by spontaneous combustion, or to ex-
plosion if the necessary conditions are present. The means
calculated to prevent accident from such irruptions of gas
comprise two classes of measures: those having for their
object the prevention of the outburst, and those intended to
protect the men from the disastrous consequences of the out-
burst. A gas-tight dam or bulkhead is often built as a
stopping to goaves. Bore-holes in advance of the work,
required by law in many States, constitute one means of
safety for the mine by giving timely warning of danger.
Nevertheless the diiTiculty of boring them in disturbed, and
consequently infested, portions of the seam is not easil_\'
overcome. The practice is sharply criticised b}- many.
314 MANUAL OF MINING.
Bore-holes from the surface to the gaseous portion of the
seam are of common occurrence in the several coal-fields of
Pennsylvania. This is the most effective of the remedial
measures. When several seams are simultaneously worked,
the least gaseous one is driven in advance of the others.
Another remedy is based on the discontinuance of heavy
blasts of explosive after the men have vacated the mine.
These dislocate the measures, cause fractures therein, and
tend to release the fire-damp. If the danger is not great, the
metliod is recommended as economical and admits of a rapid
advance of working-places.
The measures which may preserve men from the conse-
quences of sudden outbursts of gas include the use of safety-
lamps; the use of vertical air-partitions dividing the two cur-
rents coming directly from the downcast or going immediatel}'
to the upcast; and the installation of a plant for tlie rapid
evacuation of fire-damp by wide and multiple galleries and
large fans. A service of compressed-air pipes led into the
numerous districts and supplied with cocks and taps is a
perfectly rational method to employ for the increased safety
of the men.
The explosion of gas, with or without dust, which follows
its ignition is second to " falls" in the number of men
involved. The nature and extent of some of the most
prevalent conditions preceding it have long been understood.
Nothing but eternal vigilance and anticipatory action can
decrease the magnitude of the fatalities from this source, and
the disaster following it can only be guarded against b)' an
active air-current, and the exercise of precaution by stout
primary and secondary doors properly hung. A liberal
interpretation of, and a willing compliance with, the section
requiring two outlets will bring its own reward. But co-
operation must be had from the men, as neither laws nor
improved appliances can counteract the effects of their reck-
lessness.
The average percentage of accidents from this cause for
the past twenty years in Pennsylvania is 0.35 man per thousand
HYGIENIC CONDITIONS. 3 1 5,
employees, with a marked decrease during the second decade.
Some seams give off very little fire-damp, and consequently
a very moderate supply of fresh air is required to dilute it.
But even such seams as are said to be " non-fiery " should be
worked with safety-lamps, unless, they give off sufficient
water to moisten the atmosphere and prevent floating dust.
In the first annual general report of C. Le Neve Foster, for
Great Britain, his classification as to causes of explosions of
fire-damp or coal-dust during 1894 shows that out of a total
of 189 persons 152 were injured by explosions due to naked
light or imperfect lamps, 16 by shot-fire, and 14 by the acci-
dental or spontaneous ignition of mineral or other material.
Tlie causes which have led to the gradual decrease in injuries
and fatalities from explosions are, no doubt, better ventila-
tion of the mines, both by the increasing- volume of air
obtained by mechanical means, and a better application of the
air to the various faces; but there remains much to be done
to diminish the frequency of explosions, by further use of
bonneted lamps carefully inspected and of safety explosives.
The disastrous explosions of recent years which have been
caused by shot-firing are due to the secondary ignition of the
gas by the flame blown out from the blasting-agent, the ex-
plosion being more or less aggravated by the presence of
floating dust. The reduction in the amount of blasting dur-
ing the past years, and the almost entire cessation in the use
of black powder in some mines which are liable to produce
gas, has led to a steady diminution of fatalities in those
districts. Mr. Foster has very graphically shown in the
report quoted above, by a series of diagrams, a marked
decrease in the death-rate per thousand empIo}-ees, not only
from explosions, but also from all other causes which involve
underground employees in the mines of the United Kingdom
from 1851 to I 894.
In an article by Mr. Garforth on the recovery of coal-
mines after explosions, he remarks that it seems somewhat
strange that the mining world does not to-day possess a code
of rules which would be of practical use in the time of great
3lt> MANUAL OF MINING.
excitement and confusion, such as usually follow a colliery
explosion. Among the suggestions for precaution to be taken
by the manager before the accident are the following:
I. Consider the quickest and safest mode of descending
into the mine when the usual winding arrangements are use-
less. 2. Plan for the installation of a special winding engine.
3. Connect water-pipes from the surface to the mine, with
branches for use in case of fire. 4. Arrange for the fitting of
an extra engine and fan for the emergency. 5- Keep the
tracings of all working plans to within three months of work,
showing all roads then open, the position of overcast, doors,
and brattices. 6. Accustom the men periodically to travel
certain roads which they are not in the habit of talcing, Xvaw-
ing finger-boards showing the direction of the upcast pit.
7. Keep on hand all safety apparatus, including Fleuss ma-
chine, a quantity of light air-pipes, and ' 'first-aid ' ' appliances.
8. Appoint, during ordinary working of the collieries, some of
the leading officials to act as emergency officers at the time
of accident, drilling them in their duties.
Suggestive rules for guidance after the explosion are also
presented by Mr. Garforth:
1. Send for the emergency officers, assign to each his
duty, and appoint some one as deput}^ in the event of serious
accident to the manager. 2. Examine all old connections
with the shaft and arrange to repair broken stoppings. Pre-
pare stretchers and stimulants and arrange for a hospital.
3. Provide exploration parties of five with leaders, supplied
with safety-lamps, mine-plans, restoratives, cylinders of
oxygen, and a stout cord. On no account must any one
enter alone, even on the shortest journey. 4. In advancing,
the party should move in single file, the leader of each search-
party alone testing for gas. Do not let a safety-lamp be the
final guide as to the absence of after-damp. 5. Loss of life
to explorers may, perhaps, be avoided by remembering the
dangers: («) after-damp, (/') falls of roofs and sides; (r)
underground fires and consequent risk of a second explosion.
6. If the force of the explosion has blown out the separation-
HYGIENIC CONDITIONS. 317
doors and overcast, they should not be restored because of
the possibiUty of undiscovered fire. 7. Main intake air-ways,
blocked by falls, must not be traversed except by carrying
with them an unrolled brattice-cloth, which will admit of a
double current of air through the air-way. The brattice
should be non-inflammable. 8. To discover the existence of
fire, restore the ventilation and examine the return air-ways
every hour for [a] firc-stink, and (/;) a rise in temperature.
If the former be noticed, that section from which it comes
should be explored first, and its firt extinguished if possible,
or it should be closed off b)' stoppings, or, in extreme cases,
the pit entirely closed. 9. Parties should Ijc caiuful not to
go too far at once, even when taking air with lli^-m, as the
force of the explosion will have forced the after-damp into
the interstices of tlie goaves, whence it will gradually exude.
60. The causes of fire are quite numerous, and cannot be
always avoided. If the surface plant is not placed so precari-
ously as to imperil the shaft, the causes, primary and second-
ary, are careless blasting, insecure safety-lamps, inadequate
ventilation, and floatmg dust. The first three are most fre-
quently responsible for much of the danger. Explosives
whose temperature of detonation is less than 1000^ F. are
incapable of igniting lire-damp, unless the holes are badly
stemmed. Unfortunately very few available compounds real-
ize this condition, unless it may be ammonite. So the only
security lies in an almost instantaneous mixture of the defla-
grated gases with an ample supply of air, which after all is
the only preventive of fires. One of the consequences of the
replacement of the hewers by machine is that blasting, as the
other operations of mining, falls into the hands of a specialist.
This diminishes the accident rate from " shooting." A fuse
burning without flame is essential ; a means of lighting it, with-
out the fear of sparks which are first thrown off, coming into
contact with the air, is obtained in the Heath & Frost lamp.
The powder flame cannot be entirely suppressed, even by
tamping with water. So the substitution of electric firing, at
tally times, for the practice of single shots, is about the only
3l8 MANUAL OF MINING.
other means of lessening the risks. It is in the driving of the
main levels, winzes, and upraises (preparatory works) that the
dangers of the fire-damp are the greatest, because the escape
■of gases is strongest from freshly cut coal ; capillary fire-damp
is not difficult to manage, b*ut that under pressure at great
depths is serious. Often, near clay veins, the danger of ignit-
ing blowers by shots may be avoided by drill-holes, kept in
advance of the drift.
It is now conclusively established that soot is a provocative
of fire. The effect of the {presence of coal-dust has been a sub-
ject of trial and many experiments ; the most recent — those of
Wm. Hall at the British Home Ofifice agreeing with those of
the Prussian Fire-damp Commission — show that, without a fierce
flame from a blown-out shot, coal-dust in absence of fire-damp
might not explode : that it could not alone originate an explo-
sion, though, if initiated by fire-damp, soot may aggravate its
effect. This will depend upon the degree of its fineness, the
readiness of its diffusion, and its chemical composition.
Coal dust presents conditions but little less perilous than
"damp" in mines, but precautionary measures for it are
simpler than for gas. It intensifies and extends an explosion
oricrinated by gas. Without any floating dust, the flame from
a blown-out shot does not travel more than 25 feet, but soot
may convey the flame even 200 feet. A means of laying the
dust, developed in some diggings, is by a spray continually
delivered to the air-current from i" or 2" pipes under 50
pounds pressure, and a stand-pipe 3 feet high at every 50 or
70 feet. The spray is delivered through lead plugs, slit as
desired. No other jet or fibrous material gives an equally
fine spray.
Our knowledge of the influence of coal-dust and its effect
in the mine on explosions is very meagre, no important com-
mission having been appointed to supislement the investiga-
tions of the two great bodies which have already conducted
such valuable researches in this general line; but the following
brief account of the rise and progress of the coal-dust theory
is summarized from tlic Final Report of the Royal Commis-
HYGIENIC CONDITIONS. 319
sion, which, after discussing these various points seriatim, and
giving details concerning several of the great explosions that
have taken place of late years, reaches the following conclu-
sions:
I. The circumstances of many explosions, and especially
of explosions on a very large scale, and covering a great
length of the workings, cannot fully be explained by refer-
ence to fire-damp or gas alone.
II. The presence of coal-dust, and especially of fine dust,
may be the sole cause of an explosion.
III. If the coal-dust is in sufficient quantities it will cer-
tunly extend the effect and increase the intensity of an
explosion caused by any other means.
IV. Fire-damp in small quantities, so small as not to be
dangerous per se, may be highly dangerous in the presence
of coal-dust.
1. The danger of explosion in a mine in which gas exists,
even in very small quantities, is greatly increased b}' the
presence of coal-dust.
2. A gas-explosion in a fiery mine may be intensified and
carried on indefinitely by coal-dust raised by the explosion
itself.
3. Coal-dust alone, without the presence of any gas at all,
may cause a dangerous explosion if ignited by a blown-out
shot or other violent inflammation. To produce such a
result, however, the conditions must be exceptional, and are
only likely to be produced on rare occasions.
4. Different dusts are inflammable, and consequently
dangerous, in varying degrees, but it cannot be said with
absolute certaint)- that any dust is entirely free from risk.
5. There appears to be no probability that a dangerous
explosion of coal-dust alone could ever be produced in a mine
by a naked light or ordinary flame.
Some mine-fires are started in the stables, pump-room, or
at oiling-stations. The prohibition of naked lights, a care in
handling the oil and waste, and a liberal use and renewal of
clean sand and gravel absorbent are recommended.
3-2^ MANUAL OF MINING.
Sometimes, when blowers of marsh-gas ignite a mine, wet
cloths will beat out the fire. But when it has attained such
headway as not to be overcome by ordinary means, it may be
effectually confined by cutting off the air-supply and building
masonry dams, completely stopped up, if the superincumbent
strata are not porous, or the mine is not so shallow that air is.
admitted or the gas escapes. This failing, the burning portion
is hermetically sealed, and then drowned with water, or
better, CO„ . For extinguishing the fire at the Calumet and
Hecla (supposed to have been communicated to the shaft
timbers by the friction due to the binding of the rollers on
which the hoist-rope rested) all sorts of plans were resorted to :
among others, the surface was kept frozen to stop leaks ; fin-
ally, the shafts were sealed and CO, injected. For the manu-
facture of 350 cu. ft. of CO, there were used 1200 gallons of
sulphuric acid and 4500 lbs. of limestone. Water is the sim-
plest quencher, but it has happened that the water could not
reach certain portions of the mines above the foot of the shaft,
because of the compression of the air which could not escape.
Until it was consumed, the fire continued to rage above the
water-level, perhaps for a long time. On pumping out the
water the conflagration might break out again. A pipe leading
from the face of the burning portion, up the shaft, would re-
lease the air and permit quenching.
At the Anaconda mine, Montana, steam was injected into
the burning stope, but it failed to quench the fire.
For penetrating a very impure atmosphere aerophores of
different makes are to be had. They consist of a portable bag
or cylinder carrying enough compressed air or oxygen for the
respiration of a miner and his lamp while making repairs or
exploring. The oxygen is inhaled by one tube, while through
an exhaler is ejected the C0„ , which is absorbed by caustic
soda, leaving the N only to return to the bag. Fleuss' appa-
ratus looks like a knapsack, weighs 28 pounds, contains a 4-
hours' supply of oxygen, and has besides a self-contained illumi-
nator — a lamp burning methylated spirit, heats a plug of lime
and renders it incandescent, Fig. no.
HYGIENIC CO/WIIIONS.
'ill
The Fleuss diving Ivnapsack, Fig. no, consists of a
cylinder and a cell in four compartments with a perforated
false bottom. The cylinder contains oxygen at 240 pounds
pressure, and delivers the gas to the nostrils by a tube. The
carbonic-acid gas is exhaled by the diver into the cell, where
it is absorbed by caustic soda. The entire combination
carries a four hours" supply, and has done excellent service
to rescuing-parties after accidents arising from fire, inbursts.
of water or flood of gas.
The following references are cited:
Amer. Inst. M. E.: Accidents in the Comstock Mines and tlieir
Relation to Deep Mining, John A. Church, M. E., VIII. 84 , Tlie Hy^neue
of Mines, R. W.' Raymond, Ph.D., VIII. 97 , An Account of the Explo-
322 MANUAL OF MINING,
sion of Fire-damp at the Midlothian Colliery, Chesterfield County,
Virginia, Oswald ]. Heinrich, V. 148; Fires in Anthracite Coal Mines,
T. M. Williams. III. 449, An Analysis of the Casualties in the Anthra-
cite Coal Mines from 1S71 to 1S80, H. M. Chance, M.D., X. 67; The
Geologic Relations of the Nanticoke Disaster, Charles A. Ashburner.
XV. 629; Hill Farm Parish Mine Fire, F. A. Hill, XXI. 632.
Amer. Inst. M. E.: Fire-damp Report, R. W. Raymond, XXIV. 902;
Underground Fires and How Dealt with, T. M. Williams, III., 449,
Ricliard P. Rothwell, IV. 54 and Henry S. Drinker, VII. 159.
Coll. Guard.: Accidents in British Mines, editorial, Dec. 1896, 1117;
To Managers, Precautions before E.xplosions and Guidance after Explo-
sions, Mr. Garforth, June 1897, 1084; Causes of Death in Colliery
E.xplosions, Dr. N. W. Haldane, June 1896, 1220; After-damp, Rules
for Guidance after Explosion, Mr. Garforth, June 1897, 1084; Fleuss
Breathing Apparatus, G H. Winstanley, 1897, 114, An Unrecognized
Danger in Dusty Coal Mines, Jas. Ashworth, 1897,409; The Coal-dust
Theory of E.xplosions, , 1896,203; The Limitations
or Localization of Colliery Explosions, Jas. Ashworth, Dec. 1895, 11 15;
Mines, Quarries, and Factory Accidents, [uly 1895, 78; Mine Accidents
through Falls, Royal Commission, Prussia, 1897, 1186; Accidents in
Mines, C. Le Neve Foster. LXXII. 1155 ; Fencing Abandoned Mines, A
Correspondent, LXXI. 29.
Eiig. &^ M. Jour. : Ladders, Strength of Table, etc., R. G. Brown,
Inne 1897, 602; Fellow Aid in Mining Accidents, G W. King, Aug. 28,
1897, 244.
Rep. of the Twin Shaft, Pa., Colliery Disaster by Mine Inspectors, 1896,
fF. Peiina. Cen. Min. lust.: What are the Causes of Mine Explosions,
Thos. Hall Van Meter, 1896.
Rc-ft. of Mine Inspectots: Coal-dust Explosions, Kansas, 8th. 171;
Coal Dust and Gas, C. Le Neve Fibster, ist Annual Report; Coal Dust
as an Explosive Agent, C. J. Norwood, Kentucky, 1895, p. 171 ; Accidents
in Mines, H. A. Lee, ist Rep., Colo., p. 26; Accidents in Metalliferous
Mines, Frank Reed, Bull. Western Australia.
///. Min. Inst.: Coal Dust and Explosions, William Giles, II. 44;
Daily Examination of Coal iSIines, James Freer, III. 181.
Resume Conclusions du Rapport Final Commission Autrichienne
Grisou, M. Rene Grey, 1892.
Trans, of the N. of Eng. Inst. M. &^ M. Eng.: The Prevention of
Accidents in JMiiies, Austin Kirkup, XLV. part i, 2.
Coll. Mgr.: Underground Fires and How Dealt with, G. ]. Binns,
Feb. 1S94, 35, 37, 35, 52 ; Comments on Safety Lamps by Mine Inspectors
M. S. jNIartin and J. Robson, 1894, 24; Enforcing Laws, Prohibition of
Powders, etc., Protection of Abandoned Mines, Magisterial decision,
Dec. 1896,622; Accidents and How to Prevent them, Dec. 1896,610;
The same, by H. R. M. mine inspectors, 1894, 24; Tlie Physics of
Explosions, Jan. 1895. 14.
Coll. Eng.:^ Spraying Roads, "easy lessons," )uly 1896, 285;
Approaching Gas Accumulation in Mines, "easy lessons," Feb.' 1896,'
163, Difficulties in Mining, D. E. Davies, 1892, 73; Accidents froni
Falls of Roof or Sides, editorial, Oct. 1894, 60; Prevention of Roof
Falls, Joseph Hemingway, Nov. 1894. 77; the Luke Fidler Mine Fire,
Baird Halberstadt, XVI. 6; The Limitation or Localization of Colliery
Explosions, James Ashworth, XVI. iii.
Amt-r. Mfr.: Safeguard against Falls of Roof, William Jenkins, Mine
Insp., Pa., Jan. 1897, 83.
F»ART II.
PRACTICAL MINING
CHAPTER L
SHAFTS.
6i, Shafts: their location, dimensions, and shape; round 7'.f. square; sump
and subsidiary shafts ; equipment, number, and size of compartments ,
single and double entry shafts or slopes; sliafts for railroad tunnels;
mode of sinking, progress, and cost. 62. Timbering shafts; various
modes of cribbing by wood, masonry, and iron ; shaft pillars ; slope
timbering; Hollenback shaft ; walling of circular shafts. References.
61. Shafts may be sunk for permanent or temporary ob-
jects, and they may be intended for one especial purpose only
— of hoisting, travelling, or ventilation ; or their size may be
sufHciently large to warrant division into a number of com-
partments, one each for the pumping and ladder wa)', the re-
mainder for hoists, according to the output. Collieries require
additional communication with the surface for ventilation. The
large area required for, and the foulness of, the return air de-
mand a separate outlet for upcast, as also for the intake,
which should never be interfered with by hoisting.
The numerous drawbacks to single-entry compartment
shaft or slope are so fully recited in I, 5, that onl}' in \'ein.
mines should the development be thus risked. Certainly the
ventilating ways should not be in adjoining compartments,
because the bratticing could never be kept tight enough to
prevent a leakage of fresh air into the upcas';. Only the
expense of sinking in hard, or the difificulties in soft or watery,
323
324 MANUAL OF MINING.
ground preclude double entry. WJiere a prospecting drill-
hole has tested the ground the shaft should not be carried
down along on it, for the drill-hole will eventually be of
greater service as a ventilator and a ropeway than it could
be capable of during sinking.
When it is desired t3 remove the mineral quickly, several
shafts are sunk, their positions being a matter of indifference.
Ordinarily, however, the location of a shaft and its equipment
is a matter of vital import. The configuration or nature of
the surface affecting transportation may govern the selection
of a site ; but, cistcris paribus, the principal shaft should be so
located as to reach the lowest point of the workings. This is
not at the outset always possible to do, so we are accustomed
to see one shaft after another abandoned or relegated to
secondary uses. Instance the numerous illustrations from the
Lake Superior region. The Calumet and Hecla has eight
shafts, each over 3000 feet deep, and four of looo feet with a
complete plant over each one. Nor is it the exceptional case.
The prospective depths of shafts are not limited by considera-
tions of a mechanical nature. Hundreds of shafts now
exceed lOOO feet in depth where in 1880 there were few.
Shafts sunk to facilitate the execution of long tunnels are
best located with their axes in the plane of the tunnel, afford-
ing better alignment, and only because of the difficulty of
supporting the shafts at the tunnel level is it the common
practice of placing them to the side. Shafts are, however,
losing their importance for this work, since the introduction
of the rapid, ventilating, drilling-machines.
As regards form, the rectangular is the most common
(Fig. 1 1 1). Its timbering is easily accomplished, and the best
adapted to loose ground. Where brick or stone is used
instead of wood for lining, the sides are arched to give great
strength, and this perhaps led to the round or elliptical
shapes, which are such favorites in Europe on account of
their greater resistance, and particularly because of the loose
soils and watery strata encountered. That their entire area
cannot be utilized is, however, an objection (Fig. 112). The
timbering of the polygonal (12 to 16 sides), used in Belgium
SHAFTS.
325
^5^""
, TT
w
h -— -- >
and the North of France, is not so easy to fit as is that in the
hexagonal or octagonal shafts.
The dimensions of the shafts, governed by the number of
326
MANUAL OF MINING.
compartments, should be carefully studied to meet all require-
ments of strength, output, and escapement for a prolonged
period. The scale increases as the depth and output is large.
Outputs of lOO tons were regarded as large not so long ago ;
but now many hundreds of shafts have a capacity of looo tons
daily. They are larger on the Continent than in Britain, and
colliery shafts demand a greater area than do those in metal
mines, which have less traf^c, besides being restricted generally
by the distance between the walls. The size of the compart-
ment is determined by that of the bucket, skip, or cage, its
length being the width of the shaft, the length of which is
governed by the number of divisions (see 1,23 and 27). Com-
partments placed side by side make a stronger shape than if
arranged in a more compact form (Figs. 113 and 114). The
compartments for metalliferous
cars are about 4 ft. X 5 ft. :
tliose for the coal cars, from
G ft. to 8 ft. wide, by from 10
ft. to 12 ft. long, measured in-
side of the timbers. The com-
X 38 ft., and 12 ft. X 24
i
Kiii. 113. Fig.
mon sizes for coal shafts are 10 ft
SHAFTS. 327
ft., with wall plates of some even 50 ft. long. In the Lake
Superior iron region the shaft dimensions are about 9 ft. long
and 20 ft. wide. In Montana and Nevada smaller sizes pre-
vail, while in Colorado a single compartment suffices for the
small outputs of high-grade mineral. The largest shaft yet
begun is a nine-compartment shaft 38 ft. X 42 ft. in the clear.
Circular shafts for buckets holding about 1500 lbs. are 8 ft. in
diameter; for cages 13 ft. The sizes of the ventilating shafts
are a matter of indifference, so that they transmit the neces-
sary volume of air with the minimum resistance, and at a
current velocity not exceeding 1000 feet per minute. The
upcast shaft is therefore usually round, and the downcast a
walled rectangular. Neither should be housed, though the
former for a furnace ventilator may be provided with a
chimney high enough to prevent the distraction of the current
by surrounding buildings; or with traps closing tightly and
quickly if a fan is used. An area of one square foot for every
eight men employed is a good basis for the upcast of a
moderate-sized mine.
The features governing the selection of site have already
been examined on p. 20; so there remains to consider the pro-
cess of sinking. In a soft-ore lode the shaft section should
reach from wall to wall, and massive shaft pillars be maintained,
else it is sure to succumb. In hard-rock lodes the shaft should
preferably be on the foot-wall ; on the hanging-wall heavy
supports are necessary, especially if the country rock is por-
phyry.
The sinking of shafts is laborious, because of the difificulty
of putting long angling shot-holes. Small shafts are sunk by
hand cheaper than by power drills, and almost as expeditious,
unless perhaps the continuous system (see No. 91) is used ; and
the loss of time in removing all the implements for each shot
bears a large ratio to the total. Even in drifting, the actual
drilling heat is not more than half of the whole time. The num-
ber of men depends upon the size of the shaft opened ; only
two miners can drill to advantage on an area of 20 sq. ft. A
larger size gives more room proportionately to each miner, and
328 MANUAL OF MINING.
permits faster work, and in a shaft lo ft. X 1 1 ft. there is room
for three pairs of miners. This space will accommodate two
machine-drills, which in ordinary rock can make 5 ft. of advance
per day (divided into three shifts of 8 hours each), A shaft
long in proportion to its width, sunk by two or four machines,
has two centre-cut ranges of holes (see 90), which are inde-
pendently fired. The cost of sinking is from $5 to $18 per cu.
yd. Below lOO feet the rate increases each 100 feet almost as
the square root of the depth. Rziha says that in Europe the
cost of excavating shafts is from 50 to 100 per cent higher in
wages, and the cost of putting in timber 15 to 30 per cent
higher in wages than the estimate for the same amount of
tunnel-work. In the Lake Superior region one lineal foot of
average shaft costs as much as a lineal yard of gangway and a
cubic fathom (216 cu. ft.) of stoping. There is nothing but a
local criterion for the means of calculating the cost of any kind
of rock-work.
Through the first score of feet the progress is quite rapid ;
the dirt is thrown up to the surface from platforms ; beyond
this, small shafts can be carried quite satisfactorily for 90 feet
or so by windlass, but as an engine must ultimately be used, it
were better to place it at the start. The entire section is
attacked at once, a small corner sump being carried in advance
for drainage and for "bearing in " while shooting. Often a
hood is provided for the protection of the miners against fall-
ing of small rocks, and trap-doors at the surface too, unless the
ventilation is poor. If a shaft is to be prolonged while the
upper part is still in use, safety is obtained by opening only
that portion of the shaft area not under the hoistway for a dis-
tance of 12 or I 5 feet, and then widening it out to the entire size
of the main shaft. This leaves a roof of rock (" pentice "), Fi"-.
Il5,thatshieldsthemen. When another lift has been sunk, the
pentice is cut away, and another started for the next drop.
Hoisting is by underground engine or bucket and windlass.
A box-pipe, projecting -some distance into the air, from over
a stove or burning torch, will furnish almost as good air as a
SHAFTS.
329
small fan or the air from the power-drills. Except in the
neighborhood of oil and gas lines, no especial precautions are
necessary against fire-damp.
Fig. 115.
62. There is neither safety nor economy in the practice of
leaving the shaft untimbered, even if the two walls are hard
and self-sustaining, and shoot clean. To resist the thrust of
330
MANUAL OF MINING.
the country, timbering or lining is urgent (see also notes on
hoisting). This may be done simultaneously with or subse-
quent to the sinking, according to the firmness of the ground.
Each timber set is supported on its stulls, resting in notches
(" hitches ") in the rock ; or sections rest on heavy reachers at
every 25 or 30 feet of depth. Sometimes the timbers are
hung from an upper frame by spiking one set to the other.
The timbers are preferably dressed, though hewn logs are
much used for solid crib-work where plenty of help and room
is had. Their size is not a matter for calculation, as in frrm,
non-decomposing ground they experience little pressure, and
stability rather than strength is sought, the latter being se-
cured by ample shaft-pillars. Under such conditions a lining
with stiff guide-planks is suf^cient. This may consist of 3"
planks cut with shoulders in sets of four pieces, two wall-
plates and two end-pieces (Fig. 116). If cut by template or by
::^
5E^^
Fig. 117.
Fig. 116.
machine similar to Fig. 195, they need not be matched in
height. This casing is placed ia position, lined by plummet
at the corners, not spiked or joined, but simply held up to
bearings by waste rock packed close between it and the rock.
Each 30' section is held on a pair of 10" stulls. Two men can
complete one section of a 5' by 9' shaft in four days, with a
helper at the packing. The men are supported on a cradle,
suspended by a rope from the upper stulls. In very good
ground this casing will suffice for three compartments, but not
for cage use, unless perfectly backed. In bad ground a casing
of larger timber, say 8", is not infrequent (Figs. 94, 117, 118).
These are laid " skin to skin," with their ends shouldered.
SHAFTS. 331
The wall-plates are stayed by " buntons " (Fig. 1 19) bolted
or gained into them. The longer the wall-plates the stouter
the buntons, the interior side of which and of the end-plates
carry the cage-guides. The travelling and pumping ways are
partitioned off by planks nailed vertically to the buntons.
Another method, which is still better, is to have the wall-plates
break joint with the end-pieces instead of arranging the four
in a horizontal set. The reachers are hitched into the floor
and forced down against the hanging-wall. None of these
plans are practicable with inclines, which will require framing.
In framing vertical shafts the stuUs are inserted into both
walls horizontally. On the reachers four sticks are placed and
framed to the studdles or struts at the corners and at com-
partment portions. On these struts a similar set is framed 6'
above, to in turn support another parallelopiped, and so on up.
Planks ("lagging ") are driven in around these trames, and the
spaces to the rock filled with broken waste. Tlie joints of
each timber are of the pattern shown, Fig. 120. Fig. 121 is
Fig. 119.
FT
-4i>
Fig. 121
better carpentry, and quite standard. The end-pieces and
struts are usually scjuare, 8", while the wall-plates are laid 8"
vertically and 10" or 12" horizontally. The buntons art-
stouter as the wall-plates increase in length (Fig. 122). Fig. 20
332
MANUAL OF MINING.
SHAFTS. m
illustrates another form of timbering rectangular shafts with
vertical corner-plates and horizontal lagging.
Shafts such as the Comstock, 6 by 24, for prolonged, rapid,
heavy hoisting are fitted with timber as much as 14" square,
and lagged with 3" plank. Where triable rock is penetrated,
the frames are braced by inclined struts that i^revent settle-
ment. When the ground is friable, marl}--, or wet the methods
approach a caisson character. Another plan comprises a stout
framing as described, inside of which is another strong planked
cribbing, between which clay is puddled to exclude surface
water. The B. & O. shaft at Taylorsville, Ind., was thus suc-
cessfully carried through quicksand ; the outside crib was of
12", the inside of 10", timbers, with a 4" puddled wall. The
famous Hollenback shaft, 45' 4" X n' 6" inside, has a 12" clay
wall for 31 feet deep (Fig. 122). It was designed for a daily
output of 2500 tons of coal.
If the timber shows signs of giving way, other means of
securing the shaft must be invoked. With expert timber-men
the joints may be strengthened or the frame replaced, but it is
preferable to reinforce them by sets closer together. Where
the expense would warrant it, and the diminished area is not
objected to, the insertion of a second lining may secure the
works. In the Lake Superior region, after futile experiments
with other accessory modes, iron caissons were invoked. In
stiff ground they were forced down inside or outside of the old
timbers; in soft, they sank by their own weight with the under-
mining. The cylinders were in segments and sections, bolted
at the surface, keeping pace with the progress, averaging a foot
a day. A cast-iron cylinder 15' diameter, i|-" thick, was forced
down 84 feet at a rate of 2 feet per day in morainal matter.
Forepoling, a form of sheeting (see Fig. 208), is also quite
successful, but requires much timber. When the ground is
treacherous there is a constant contention against the rising of
the bottom. In the event of this happening, the simplest
plan is to floor and brace the bottom, advancing the small
opening by forepoling (Fig. 104) and subsequently enlarging
the shaft to its full dimensions.
For circular shafts the framework descends with the shaft
334
MANUAL OF MINING.
in sections, whicli, however, are built upward from reachers,
bedded whenever suitable foundation offers; or the "curbs"
rest on a properly dressed ledge of the rock, and are firmly
wedged against the sides. The timbers, assuming the charac-
ter of voussoirs, are hooped with iron and called " curbs." The
timbers composing the curbs may be mere wedge-blocks, or
are long enough to form a regular polygon, when they are
held by dogs. In ordinary ground the sets are held apart by
props, and the solid-packed lining backs them. Otherwise they
may be formed into a solid walling, often suspended from a
heavy frame at the surface by iron rods. In any event the
Fig. 123.
joints and fitting receive the greatest care, and many of the
old shafts are high types of the carpenter's art.
The increasing scarcity and cost of large timbers, the ex-
pense of fitting and maintenance, their short life, and, finally,
the corrosion of spikes and splice-plates, with the consequent
leakages, have caused the abandonment of wood tubbing, and
the adoption of iron and masonry for all permanent ways.
The effect of the heavy, hot atmosphere of the mine upon
timbers is a decomposition, that is not always detected on the
SHAFTS.
335
surface, but once begun, only better ventilation can delay ulti-
mate destruction. Dry timbers should be frequently probed ;
alternations of wet and dry are exceedingly destructive ; wet
timber will last longer than dry. Preservatives have been at-
tempted, with much success. In salt-mines steeping in brine
gives great endurance. The sulphates and chlorides of zinc
have proven excellent antiseptics ; and a grand opening offers
to the discoverer of a means of freeing the lead ores of the
Western States of the obnoxious zinc, and at the same time
utilizing it as a preservative.
The use of masonry for the walling of shafts involves
but one disadvantage it presupposes ground that will stand
safely for a couple of weeks without much support. Before
the permanent structure can be introduced, a considerable
depth must be reached, to obtain a sure foundation upon
reachcrs, or upon a ledge, from which the masonry is erected,
the temporary timbering and bracing being gradually removed
as the construction proceeds. When a very secure ledge or
base cannot be had, a wedge-shaped chamber is built for some
distance back into the rock from which the solid crib supports
the walling.
If the pressure rom the walls is not great, the brick or the
lode-rock is built up in plane walls, packed behind by waste.
Often the mine water carries matter in solution that cements
the whole into one solid, mass. When great pressure is ex-
pected, the sides are arched toward it ; and in very bad ground
all four sides are curved, or the circular form is adopted. The
arc should be such that its chord is perpendicular to the
direction of pressure. In such event, the foundations for the
sections are curbs of overlapping timbers patterned to the curve,
or of late years of cast-iron, with slabs of wood at the joints.
The packing behind is carried up with the brick or masonry
until the ledge of the upper section is reached, when it is
removed gradually and the two sections united. In some in-
stances the masonry compartments are built at the surface and
lowered into place. Brick is well adapted for quick arch-work.
The wall of a shaft 13 ft. in diameter is four half-bricks thick;
336
MANUAL OF MINING.
the labor of laying it from a staging is one and one-half days
per M. The masonry is supported by rods, b (Fig. 124),
from beams a, a, buried firmly in the walls.
Fig. 125.
Masonry is heavy to support, and not any cheaper now
than iron, with which many shafts are successfully curbed.
Rings of I beams or channel-bars form the curbs, upheld at
proper distances apart, by struts of wood or iron, and backed
by heavy planks or -^-^ sheeting (Fig. 112). English engmeers
use old railroad iron similarly. Prepared at the surface, the
curbs may be lowered into place and quickly set, with little
labor. A packing of concrete is used at Saarbruck, giving
increased strength and durability. It is estimated that the
SHAFTS,
337
iiiituii cost of lion lining in place is twice that of wood and
equal that of masonry, but the cost of maintenance is one
Fig. 126,
third that of wood
the shaft is dry.
Fig-. 126 illustrates the mode of
timbering a shaft in firm ground by
sets of unhewn timbers at 3 to 6 ft.
apart, lined with vertical planking.
The following references are
cited :
Pa. Mine Iiisp. :
Bleu'itt, 1885, pocket ;
Co//. Eng.
W. Stewart.
Fig. 127.
and nearl}' tlie same as with masonry, if
Shafts, Patrick
;md 1 086, pocket.
Laying Out Shaft ISottonis,
Dec. i8q6, 18S; Timbering
Fig. 128.
Brout
B. H'.
h, Dec.
Brouali
TS96,
Dec.
Leith Coal Sliaft, H. L. Auchmuty, ,^ug
1S96, 3 ; Sliaft Pillars, W. Stewart, Dec.
1896, 1S9; Shaft Sinking,' and Equip-
ment, J. T. Beard, 1894, Sept, and Oct.,
27 and 51.
Co//. Guard.: Deep Shafts of the World, B. H.
1170; Deep Mining, Decreased Capacity of Shafts,
1S96, 1170; Shafts, Safety Props for Cage, C. B. Smith, Dec. 1896, 1 1 23 ,
Sinking and Lining a Shaft at a French Colliery, M. Ainie Gardon,
LXXIf, 868; Mining at Great Depths, B, I-f. Brough, 1896, 1170,
Making Good, after a Fall, a Shaft at the Lievin Colliery, M. Desailly,
Oct. 1895, 6S3 ; Adaptation of an Air-sliatt for Winding, M, P, Van-
hassel, LXXfl. 1010, Shaft Smking m Germany, H. Huhn, LXXlf.
932.
Co//, ilgr.: Tiiribering .Shaft, Coal Mmes, Wm. Bradford, Nov. 1896.
Jour. Assn. Eng. Soc: Tnnbcring Shalt, Poe, XV., 20,
Min. Inst. Scot.: Notes on the Sinking of Shafts and the wav iliev
are fitted up for Winding and Pumping, Robt. Beith, Vfff. 234.
E. &^ M. Jour.: Electric Light in Shaft Sinking, |as. Baird, L\'l.
393; Deepest Shafts in the World, Tamarack, editorial, LVll. 505;
Sliaft Sinking and Timbering at Bertha Zinc Mines, W, H. Case, LVI.
474; Progress of Shaft Sinking, H. H. Webb, May 22, 1897, 507,
CHAPTER II.
SINKING IN RUNNING GROUND.
63. Precautions taken to exclude water ; tubbing ; description of and
estimates for Triger's metliod. 64. Kind and Chaudron process of
tubbing and sinl( i 1 ft. was sunk through 26 ft. of
quicksand, the frozen wall enveloping it being 7 ft. thick, at
a cost of $190 per foot.
References follow:
///. Mill. Ins/.: Sinking through Quicksand, Peter Jeffrey, II, 90,
230, 240.
N. of Enj^'. M. &^' M. Ins/.: Tubbing, widening, and retubbing,
XLVI., Part 3, 38.
Coll. Gicard.: Dealing with Water during Sinking, Institution of
Civil Engineers, j. B. Simpson, May 1897, 995; Freezing-process Sliaft-
ing at Anzin, M. F. Schmidt, July 1S97, 149, LXXI. 561 ; Sinking and
Tubbing Simultaneous, Leon Thiriart, Feb. 1S96, 272; M. Aime Gardon,
Nov. 1896, 868; Nov. 1895,925; Sinking with Congelation, 1897, 149.
Coll. Mgr.: Sinking through Quicksand, Prof. Lupton, 1894, 77;
Poetsch System, 1894, 91 ; Cast-iron Tubbing, A. Lupton, |an. 1S95, 16.
Coll. Efii;.: Triger's Method of S'nking, XV. 18; Water Dams in
Shafts, XV. 42; Freezing Water an .\id to Mining, XV. 86; Freezing
Process, Gobert, XVII. 171.
The School of Mines Quarterly : Sinking of Shaft " B," Barnum
Mine, Ishpeming, Mich., R. H. VoikI\-, May 1882, 277 ; Shaft-sinking in
Quicksand, Rich. A. Parker, XVI. 34.
Amer. Inst. M. E.: A New Method of Shaft-sinking through Water-
bearing Loose Materials, James E. Mills, XIII. 216; The Kind-Cliandron
Process for Sinking and Tubbing Mining Shafts, Julien Deby, C. E., V.
117.
E. &^ M. four.: Saclise Process of Sliaft-sinking, LVII. 320; Shaft-
sinking thiough Quicksand, LVII. 30; Shaft-sinking with the Aid of
Divers, Prof. G. Nordenstrom, LVII I. 57.
CHAPTER III.
TIMBERING.
65. The use and preservation of timbers ; for jointy rock, horses, and
disintegrating rock ; consumption of timbers in mines ; selection of
timbers. 66. Props, sprags, stulls, and their plates ; formulae for
strength and the calculation of their dimensions ; variety of joints.
67. The construction of setts, frames, etc., for various conditions of
roof, walls, etc. ; timbering for levels, gangways, gob-roads, and for
support of vein, gangue, etc. ; in salt mines; lagging; wood, iron,
and masonry for levels. 68. Square setts, joints, and sizes of parts;
full account of the American method ; cribs for rooms ; timbering of
mill-holes, underground chambers, plats, and winzes; timber-man's
tools; framing-macliines. References.
65. When one examines the story that the accident-tables
of page 306 tell, it becomes manifest how the neglect of a few
simple rules endangers life and property ; and in no respect is
this more painfully impressed than by the mortality record of
unpropped rock. Excavations, even in the " rock of ages,"
cannot be left open any great length of time without support,
which, if introduced in time, will prevent disastrous results.
Successful superintendents personally watch the timbering
and the face-rock diligently, and guard against any springing
of the walls. All the effects of pressure are intensified by
neglect, and the secret of success is to place timbers before
movement begins. Supports are not for bad roofs only; while
"awaiting a weak spot, the good roof, so called, catches him,"
and his stope or room is lost. The eagerness to quickly win
the face, while pardonable, promotes avarice, parsimony, want,
and then provokes collapse.
Though the conditions underground are such that very
34S
TIMBERING. 349
simple timbering is required compared with that on the sur-
iace, the tendency of the time is toward the employment of
special timber men to n:al%?;:i^^^''<:^X;^^'^^x/X^:>^^
t-_
J^l
^.^
T^
\^^^
=-S
n
M
\
\_
\
<'-|t
/"^^
\
\
t\ ! ■ 1 1 i \-.
394 MANUAL OF MINING.
ceding the main work. It is of \" plates, 12" a 24", riveted
togetlier by means of flanges ; and when a cut has been
excavated into the heading large enough, one of the plates is
placed and held by props (often the plates are held by com-
pressed air during the work), on each side other cuts are
made for two more plates, which are riveted to it. Rings of
the pilot are thus successively completed.
Around this, in small terraces, and considerably behind
the pilot, the main shell, 17' in diameter, is finishing in a simi-
lar manner, the plates being propped from the pilot-tube,
wliich is always braced from the masonry that lines the shell.
With its progress the rear rings of the pilot tube are removed
and their plates shifted to the front end. The masonry con-
sists of six courses of brick laid in cement. To reduce the
volume of the tunnel that is kept under the compressed air,
brick bulkheads, 4' thick, provided with two air-locks, are
built every 400 or 500 feet. Only the two nearest the work
are maintained.
What'^ver the procedure, the masonry is built on centres
and by template, for invert and walls. The centres should be
made of light, small, easily-framed sticks, that are not so close
as to interfere with work, yet strong enough to support the
thrust that may fall on them when the tunnel-timbering is re-
moved. Its shape may be whatever is the most convenient for
the traffic. The elliptical linear arch is, however, the form most
commonly adopted, the side and roof comprising the upper
part of the ellipse, which is closed below by a segmental in-
vert arch, with the springing lines on horizontal faces. In
stratified rocks, the strongest form for the roof is that of a
pointed arch. Sometimes in solid lock the horse slioe form
is used for the top and sides, the floor being level
In preparing to tunnel silt, both the weight and the vertical
pressure of the overlying material and the lateral movement
of the loose paste are to be resisted. The first is a matter of
determination, and the abilit}' of the completed structure to
withstand this is also a matter of mathematical calculation;
but the second is the difficulty to be apprehended. The
i:r^ive is fired, the tension of its gases acts in
all directions upon the confining rock. Where the resistance
is least, a tendency to rupture takes place. With powder the
gases find time to concentrate their pressure upon the line to
the nearest external point, and, perliaps, may break off a cone
of rock. The high explosive, on the other hand, is so instanta-
neous that a concentration of force is not effected, and the rock
will break any^vhere as soon as at the weakest line.
The placing of holes should have due regard to the struc-
ture of the rock. Whether of igneous or aqueous origin, it is
444
MANUAL OF MINING.
traversed by a congeries or by systems of planes which rive the
rock into more or less regular blocks. These rifts, cleats, or
seams constitute the lines of slight resistance which are advan-
tageously employed as lines of rupture. The quarrymen
endeavor to select them on which to split the stratified rock
by lewising or wedging. In the work of removing the more
massive rocks, even in a fractured condition, the crevices or
free faces may avail.
Under no condition can the miner arbitrarily select the
lines of fracture, except it be in " tight" ground and massive
rock. He then depends upon the shortest vent from the ex-
plosive chamber to the surface, and is guided thereby. Any
clay seam, gouge, or fault is hailed as a welcome accessory.
By "tight" ground is understood that which presents only one
free face, — containing no protuberances or cavities.
In each case the line of least resistance is the objective.
The shorter it is, or the more brittle the material, the less or
the weaker may be the disruptive agent. To secure this with
the minimum of drilling requires the instinct which experience
imparts, but a few rules may assist the judgment.
A hole should not be on the line of least resistance, though
it may be in its plane. If a known gouge, fault, or crevice
traverse the rock, the direction of the hole should be normal to
that plane, and for the reason that the explosive will find vent
along it the hole need not be carried down to the seam. The
hole will break to a. Fig. 2 19, if the powder is disposed wholl}'
within the bottom layer. Sandstones and liiTiestones are
better split by weak powder; a
strong one may pulverize a large
portion of it without breaking-
stone. The roof holes are usually
fired first in driving; a face through
strata pitching toward the men
(Fig. 199); the bottom holes pre-
cede the uppers in a reverse pitch. With sufficient explosive
the amount of material removed is measured by the entire block
of stone from the face to the plane of the holes (Fig. 220).
Fig. 219.
BLASTING.
445
Colliers avail themselves of the cleat in coal, which comes
away with great freedom if properly attacked. Generally it
has one direction only, sometimes two, producing cubical or
rhombohedral coal. In flat seams the trend of the main cleat
determines the direction of the attacking breasts and, cor-
respondingly, the order of mining. The most important gal-
leries are run with the cleat, and the headings perpendicular to
it are called butts. In pitching scams the dip is of more im-
portance than the cleat.
Homogeneous rock, and particularly massive rock, has no
crevice or seam to assist the miner to its displacement, and an
additional element is added to his work. He must consider
not only the volume of the rock to be re-
moved, but also the state in which the shot \
will leave the face. In otlier words, each
blast is a " bearing-in " shot for the next
succeeding (Fig. 221). In stratified rock or
seamy ground the shooting is to the joints,
and the stone breaks well, just as if the scams
are open faces. Porphyry and quartz is al-
ways "tight" ground, i.e., there is no scam to
shoot to ; there is only one natural face for
attack. The careful and experienced miner wi
to benches which will offer favorable opportunity to displace
large masses with little powder.
Where simultaneous firing is practised upon several neigh-
borine holes, less heed is paid to this matter, for one cannot
foretell the shape or volume of the cavities opened. Generally,
several holes looking toward one another are fired merely as
bearing-in holes to facilitate blasting. For this same reason,
the procedure by machine is entirely different from that b)'
hand ; all the required number of holes decided upon are
drilled in one heat before any blasting is attempted, and it
does not signify if a hole or two too many is drilled ; so the
cost of dynamite is naturally higher than by hand, of steel
consumed, more, and of labor, much less.
Manifestly, with single holes, the miner must drill the hole
see to break
446 MANUAL OF MINING.
with some reservation as to future needs, and so place it as to
accomplish as much as possible with the explosive. The two
forces to be considered — the strength of the powder and the
resistance of the rock — may be known, the first, accurately, the
second, varying with the cohesion of the rock approximately.
The drilling resistance is not the same as the shooting resist-
ance. Trap, granite, and syenite are firm and brittle ; they
are hard drilling but easy shooting. Pink quartz neither drills
nor shoots well. Dolomite, amygdaloid, limestone, and por-
phyry drill easy, but break short. In other words, the com-
ponents of the rock may be hard, but if the grain is open it is
not difficult to work. Drinker's " Explosive Compounds"
gives a table of relative resistances of different materials and
the coefificients of their toughness. Having, besides, the co-
efficient of the rupturing effect of the explosive upon a certain
material, the excavation may be ascertained from the formula,
W= CL\
in which W is the weight in ounces of the disrupter ; L, the
distance to the face in feet ; and C, the charging coefficient
dependent upon the rock. In a given mine, the value of C
may be experimentally evaluated by repeated trial. And the
rational loads in any other case are thus fixed with a moderate
degree of accuracy. Thus, if a 27-inch hole shows an average
of 0.5 oz. of dynamite No. i, C" is 0.38. A subsequent 40-inch
hole, under like conditions of rock and agent, will require 3.3
oz. The volume of rock thrown is estimated to be approxi-
mately equal to the cube of the line of least resistance, though
it will be greater with several open faces. Against one face
only a shot breaks out a funnel approximately conical.
The relative position of the line of least resistance varies
somewhat with the position of the hole and the condition of
the face. It is the line of general throw and rupture, and
extends from slightly below the centre of the explosive to the
nearest external point (line ab, Figs. 222 to 225), measured
perpendicular to the free face or to the direction of the hole.
BLASTING.
447
In soft rock, with a moderately slow explosive, the line
may be quite long comparatively, but the same powder in
tough rock cannot get far awaj' from the face, and ab is small;
Fig. 222. Fig. 221. Fig. 224. Fig. 225.
while with medium rock it may be three-quarters the depth
of the hole.
If the hole be placed as shown in Fig. 226, the hole
becomes the line of least resistance, and a "pop" shot
Fig. 2-h. ].■,,;. ;.2j.
results, no matter what the rock. So, too, d. Fig. 227, fails
to break; e has a very short line to break, while f is about
rieht, in the average rock.
Fig. 229.
With common powder the holes cannot exceed an angle of
45^ with the flush face. With dynamite, 60° is a limiting
.angle for almost any variety of rock. A larger angle is advised
448
MANUAL OF MINING.
only when a free face offers a hollow or bunch (Figs. 228 and
229). Such an exigency, while it may require a deeper or a
shallower hole than that of the average hand work, increases
the efificiency of the blast. In Fig. 229, hole 2 will displace
more than hole i with equal powder and work. Fig. 203 illus-
trates an unfavorable hole. If very deep it will blast out to ks.
A hole, oin, will do proportionately better for the same
l"ir:. =v- Fig. C32.
weight of powder and much less drilling ; but tlien the subse-
quent removal of the block of ground biiisk will require nearly
as much powder as for the original hole, ok, the line of
resistance being the same.
Blasting in homogeneous material is more satisfactory than
in short fissured rock, which can only be worked with shallow
holes. It is also true that drilling uniform rock, even if hard,
is preferable to putting holes in variable rock. In large galena
BLASTING. AA9
veins, deep, narrow holes do great execution ; so " squibbed "
holes in the flint-zinc-lead beds of Missouri. The direction of
the holes relatively to the earth has no influence pro or con.
Vertical or horizontal holes are equally effective, other things
being equal, except that in shelly ground horizontal holes are
preferred because of smaller liability to caving in.
Occasion arises when it is desirable to have deep holes —
the ground maybe brittle and coarse-fissured ; or, occasional!}',
a deep hole maybe desired in hard rock, and sufficient powder
to do the work cannot be crowded down into the hole. In
such event a chamber is prepared by exploding a light charge
of giant under heavy tamping. Into the cavity tlius created
is tamped ample explosive for the purpose. This process is
called "squibbing."
Expanding bits are also used to accomplish the same pur-
pose (Fig. 231). When the desired depth has been reached, a
pair of cutter-wings are forced out (Fig. 232), and in rotating
cut out a hemispherical chamber. In soluble rock, acid poured
into the hole will eat away a space for the powder.
When a streak of rich and brittle, or soft, mineral is to be
recovered from an extensive exposure, it is blasted separately
from the rock, which has a different degree of tenacity. Long
lightly loaded holes are drilled in or alongside of. the ore. On
this account hand-work is more economical than machines in
mines of high-grade thin ore streaks. In shafting it is seldom
that any attention is paid to the reservation of ore, so that
the methods more commonly adopted are similar to those
used in driving. In a shaft long in proportion to its width,
two centre-cut craters are separately fired.
The following references are cited :
Trans. M. &= Af. Eng.: Experiments with Safety Explosives, Berg-
assessor Win kliaus, XLVI. 17; Safety Explosives, Bergassessor Wink-
liaus, XLV. (2) 141 ; Dangers of Percussion Fuses, XLVI. 41.
Coll. Eng.: Flaineless Explosives, Report of Committee, A. C. Kayll,
.\pril 1896, 20S ; Detonators, Dec. 1895, Blasting in Fiery Mines, Franz
Brzezowski, April 1896, 209; Relative Cost and Efficiency of Powder,
May 1897,459; The Eflfects of Different Explosives on Coal-dust, Wink-
haus, 1S96, 39; Explosives for Coal Mines, Vivian B. Lewis, XVI. 150;
Modern Development of Explosives, V. B. Lewis, Mar, 1895.
450 MANUAL OF MINING.
Coll. Guard.: Electric Ignition of Blasting Explosives, Oct. 1896, 792 ;
Electric Ignition of Blasting Explosives, B. Heise, Mar. 1897, 598:
Electric Firing, J. von Lauer, Jan. 1897, 161 ; Dynamite, Accidents and
Prevention, James Ashworth, Nov. 1896, 937 ; Higli Explosives, W. J.
Orsman, Jan. 1897, 168 ; Explosives, W. J. Orsman, Nov. 1894, 835 ; Ex-
plosives in Belgium, Victor Watteyne, Jan. 1897, 208 ; Belgium Regu-
lators, Belgian Royal Decree, Jan. 1896, 209; Percussion Fuses and their
Suitability in Fiery Mines, J. von Lauer, 1896, 258; List of Flameless
Explosives, Copy of Orders, June 1897, 1129; Prevention of Accidents
from High Explosives, James Ashworth, Nov. 1896, 927; Explosives,
Henry Louis, Feb. 1897, 302 ; Water-cartridges in Blasting, L. Jaroljmek,
LXXI. 162 ; Influence of Diameter of Holes in Blasting, J. Daniell,
Dec. 1894, 1088; Elements of Defectiveness in Shot-firing, reprint, Dec.
1894, 1088; Diminished Use of Explosives in Belgian Collieries, Victor
Watteyne, Aug. 1895, 299; Experiments for Ascertaining tlie Com-
parative Effect of Explosives, Bergassessor Winkhaus, Sept. 1895, 539;
Nature and Use of Industrial Explosives, ]. Daniell, Mar. 15, 1895, 497 ;
Dec. 1894, 10S8 and 1134; Explosives and Detonators, J. House, Mar. 22,
1895, 546.
Coll. Mgr.: Shot-firing by Electricity, P. Mehers, 1894, 241 ; Use and
Value of Explosives, C. J. Thomson, Jan. 1896, 15 ; Explosives, J. S.
Martin, Nov. 1896, 582.
Bureau of Mines, Ontario: Use and Abuse of Dynamite, A. Slaght,
1895. 285.
E. &^ M. Jojir.: Smokeless Powder, LVI. 117; Report on Flameless
Explosives, A. C. Kayll, LVIII. 556; Testing Explosives for Coal Mines,
LXI. 567; Negligence in Blasting, LXI. 186; Explosives in Belgian
Collieries, Victor Watteyne, LIX. 364; Manufacture, Use, and Abuse of
Dynamite, Harry A. Lee, LXI. 182.
CHAPTER VIII.
DRILLS AND DRILLING.
85. Channellers and quarrying machines ; cost, economy, and use ; tools
needed; steam and pneumatic power. 86. Percussion drills ; requis-
ites for a good drill ; construction ; valves and improvements ; de-
scriptions of the different drills in the market. Rand, Sergeant,
Ingersoll, Burleigh, Schram, and Darlington. 87. Rate and length
of stroke in hard and soft rock ; drifting, sinking, and stoping by
machme; relative cost and progress by machine and hand labor;
shapes of bits, tools, connections; column -c's. tripod. 88. Diamond-
drill; description of machine; operation; gear and hydraulic feed;
solid and annular bits ; consumption of stones. 89. Rate of progress;
economy, cost ; its function as a prospector; mode of keeping its
record; Brandt's drill ; electric drills; perforators and entry machines.
90. Size and depth of holes; system of arranging holes; Mt. Cenis
and St. Gothard system; the .'\merican "centre-cut" system. 91.
Brain's radial system ; progress, cost, and ratio of cubic foot broken
to the foot of hole ; Gen. Pleasant's method of long hole or continu-
ous drilling by diamond drill. 92. Coal-cutting machines ; discussion
of the types ; comparison of the work done, with hand-labor ; account
of the Harrison, lefifry. Sergeant, Lincke, Winstanley, Marshall, and
Frith's machines ; electric cutters. References.
85. The successful substitution of machinery for hand-
labor has proved a most important advance in engineering.
The extraction of fuel, ore, and rock is more economically
and rapidly accomplished with greater comfort and safety to
laborers ; hard rock is no longer an obstacle, and very long
and large tunnels are rendered possible. The time spent on
preparatory workings is shortened, and this element of time is
an important consideration in the rapid opening of, and quick
returns from, mines. As machinery never " strikes for wages
451
452 MANUAL OF MINING.
or time," irregulaiities and "shut-downs" are less frequent
than formerly.
Every form of hand-labor tool has been successfully imi-
tated and extensively introduced. The quarry methods of
lewising (p. 429), "jumper "(p. 41 iV saw, chisel, pick and
auger, find their counterparts in the channeller, percussion-drill,
coal-cutter, and diamond-drill.
In days of yore the quarrying of dimension-stone was ac-
complished by the trenching along lines decided upon. Car-
ried often to 10' depth and wide enough for a man to operate
his pick, these trenches wasted much good material. The
channellers and gadders now used dig these trenches as deep
as desired, but only 2" or 3" wide. These machines are
mounted in different styles, and cut perfect!}' true lines at any
angle with or across the strata.
For extensive quarries these machines are mounted on a
portable sliding carriage, with boiler, rails, etc., and a feed
which automatically moves it with the progress of its channel.
A set (gang) of five cutters i-eceives a reciprocating motion
from a steam-piston, through a connecting-rod, or through
some yielding contrivance from the crosshead of the engine.
The latter gives an elastic blow to the cutters. Automatic con-
trivances keep the cutters to their work. Machines are also
supplied for cutting two channels at a desired distance apart ;
these are known as "double-gang machines," and cost from
$1200 to $2000 complete. With 3 men and 400 lbs. of coal, at
I 50 strokes per minute, they cut from 75 to 400 sq. ft. of stone,
—the former in marble, the latter in soft lime, — and replace 50
men.
Many quarries employ, instead, a steam or air drill, mounted
on and traversing longitudinalh- a long stout bar, which lines up
the work. This frame is comparatively light, and is adjustable
to a high or low position and for vertical or horizontal holes
(Fig. 2; 3). With this a channel is cut to the length and deiuli
desired ; or an X-bit drills round holes, at certain distances apart,
to full depth, the partitions between to be broken down by a
broaching-bit(Fig. 233), or shallow holes are drilled for plug and
DRILLS AND DRILLING.
4S3
feathers. 300 linear feet of 2' holes arc "put " in 10 hours, or
70 sq. ft. of channel ; in granite, 28 sq. ft. of channelling is done.
The U. S. Census Reports show the cost and progress in quarry-
ing to be very varied, with a marked improvement over hand-
labor in both respects. Moreover, the value of the stone is
enhanced, being less shattered, as also the value of the quarry,
because all the stone is saved. In Vermont the Ingersoll per-
cussion and the Sullivan diamond-drill are used.
A tripod can be had arranged with a slot movement to the
drill body, so that, with one setting, three parallel holes can be
drilled for " complex lewising."
In limestone quarrying 5-foot beds, 23 holes of 7" depth
can be done per day by hand, and 400 by machine. In blue-
lime, steam-power drills are seven times as rapid and one-fifth
as cheap as hand-work.
86. Power-drills depend upon percussion for penetration
of the rock. A steam-cylinder, sliding in a guide bed-plate,
mounted on a tripod or column, and a cutting-tool clamped
454 MANUAL OF MINING.
as an extension of the piston-rod, comprises the mechanism,
which has attained a simplicity of parts that has made it the
" chief element of mining success." C. D. Lawton, Commis-
sioner of Mineral Statistics of Michigan, says that " in the prog-
ress of Lake Superior mining two forces must be allowed to
have the precedence before all others — the air-drill and giant-
powder."
Its comparatively small weight, 200 to 350 lbs., makes it
portable, and yet it has enough metal to withstand the extremely
hard usage it must receive. It occupies a small space, and can
be set up in a stope or room without greatly interfering with
the removal of broken rock, and will drill holes in any position
or direction.
Steam is the motor fluid above ground, and compressed
air below, with an ordinary pressure of 50 to 80 lbs. per sq. in.
The horse-power of the drill is estimated as a simple steam-
engine, with the important difference that the ratio of the area
of piston-rod to piston is larger. Again, the steam-engine does
its work throughout the entire stroke, but the drill-engine
only at the end of its stroke. Hence it can never work ex-
pansively. The air enters the cylinder and propels the piston
to the end of its stroke, and the attached drill strikes the rock.
At that inoment the piston reverses the valve, which admits
air at the lower end of the cylinder, while a ratchet and spiral
device slightly turns the tool, which is being drawn back for
the next blow. As the work to be done on the return-stroke
is merely to lift the tool, the annular area of the piston is but
half that on the other side, and little power is consumed. At
the proper, point in the up-stroke the valves are again reversed
and the operation repeated.
The rapidity of the blow varies with the ability of the ma-
chine, and is altered to suit the hardness of the rock. The
speed averages 200 blows per minute. A short stroke, light
blow and rapid rate give the best progress in hard rock, and
a hard blow is best in soft rock, provided the drill does not
" stick " in the hole. High speed may be desirable to attain
rapid penetration, but kinematic difficulties place a limit to the
DRILLS AND DRILLING. 455
speed. A maximum of effectiveness is obtained when the full
air-pressure is exerted at the moment of the blow. So the
valve should not reverse until that instant, and then instantly,
without " dancing "; nor should there be any back-pressure on
the lower side of the piston. To do this rapidly and accu-
rately was the problem.
It is in the solution of this, the predominant feature of drill
mechanism, that the Sergeant, Rand, Ingersoll, and Burleigh
types have survived the active competition, in this country ; the
Darlington, the English favorite, accomplished it in a different
manner ; while on the Continent the successful native machine
is the Schram.
There are two systems of moving the valves, — the tappet,,
requiring levers, and the duplex, requiring a fluid. The
first has long retained its place. In all the early forms of drills,
except the Wood, the valve was operated by means of an ex-
ternal rod from an exposed three-arm tappet, moved by a pro-
jection on the piston-rod. This is the principle of the steam-
pump, but its slow speed does not give rise to the trouble that
was found with power-drills, in which the numerous and violent
shocks caused the breakage of the moving parts, particularly
in a cold atmosphere. During the progress of the Hoosac
Tunnel, so continual were the repairs, that a perpetual stream of
men was passing, carrying some piece of the machine.
These repairs, the loss of head and of power, because the
valve is reversing before the piston has completed its stroke,
the danger of knocking out the cylinder-head if the tappet
fails, and other early objections to the tappet, were gradually
overcome. The tappets were concealed, the arc of their motion
■yvas reduced, and the form of the machine was rendered more
compact. Many of these disadvantages were inseparable from
the form, but the fact that a positive valve movement is ob-
tained and that it is safer in the hands of unskilled labor, ex-
plains its retention.
In the Burleigh, the piston operates two rockers, which in
turn oscillate the valve. This requires more dead-space and
consumes more steam than the improvements adopted in the
4S6
MANUAL OF MINING,
"Little Giant," Fig. 234. Its valve is thrown by a centrally
located three-arm rocker, that insures a positive motion. The
•durability was increased by separating the spindles from the
Fig. 234.
valves and tappets which they connect. The Sergeant tappet
has the valve and the rocker in one three-armed piece. In
both, the movement is effected by contact with the inclined
planes on the piston.
DRILLS AND DRILLING.
457
The other valve mechanism is that adopted in the " Slug-
ger," Sergeant, Ingersoll, and Schram. It embraces a steam-
moving valve, which admits of
higher rate of speed. The
" Eclipse," Ingersoll (Fig. 236),
and the Rand "Slugger" (Fig.
235), are of similar action. Twe
port-holes connect the annular
groove in the piston with each
opposite end of the valve-chest,
and are opened or closed by
the piston passing over them ;
the supply for one end, and the
exhaust to the other end of the
valve-chest, are simultaneously
opened. The annular groove,
therefore, is a general e.\haust-
outlet for the valve steam, while
the motor steam is e.xhausted by
the valve connecting the inlet
passage with the exhaust-pipe.
The sectional views (Figs. 235
to 237) show the connections
clearly. When the piston and
cylinder wear away slightly, the
steam-pressure works to the
wrong end, the exhaust becomes
imperfect, and the valves fail
to act properly.
In the Sergeant (Fig. 237),
the piston-valve is moved by ex-
haust steam from the opposite
ends. An auxiliary slide-valve
moves over the arc of a circle
by shoulders on the piston,
opens and closes the ports, and is a trigger regulating the
movement of the main valve. There are no openings in
DRILLS AND DRILLING. 459
the side of the cyhnder, and no ports for the piston to close;
the exhaust remains open at one end till the blow is struck,
when the valve reverses immediately.
An account of the Schram and the Darlington drills is to be
found in "Andre's Mining Machinery," from which the follow-
ing is taken : " Schram's consists of a slide-valve and a slide-
rod that admits steam to the cylinder for raising the piston
and drill. When the piston passes a certain front port-hole,
steam enters through it into the back of the valve-chest, at the
same time that the front valve-chest, through the other port
and the hollow circular groove of the piston, communicates
with the exhaust-pipe. Steam then works full pressure on the
slide cylindrical rod, which, with the slide-valve, is forced to-
wards the front valve-chest, so that the back steam-passage is
open to the cylinder, and the front steam-passage connects with
the exhaust pipe. The piston moves forward, and, when it
passes the back port, allows the steam to enter the front valve-
chest at the same time that the back valve-chest, through its
back port and the circular groove of the piston, communicates
with the exhaust. The slide-rod is forced back, the front
steam-passage opens, and the back passage communicates with
the exhaust. The slide is in the form of two spindle-valves, so
that it remains in position without recoil, and the annular
groove of the piston is always in communication with the
exhaust.
" The Darlington has only two working parts, — an extreme of
simplicity: a cylinder and its cover, and a piston and its rod.
The piston is made to operate as a valve. The inlet pipe, hav-
ing open connection with the cylinder, akvays furnishes the
pressure to lift the drill, which rises whenever there is no press-
ure on the back. On its way up, the piston first covers the
exhaust (above the inlet), and then uncovers an equilibrium-
passage, by means of which communication is established
between the front and back ends of the cylinder. Then air or
steam enters and operates over the greater area, at the back,
and first checks the upward movement, soon overcomes it, and
finally produces a forward motion. The propelling force, now,
460 MANUAL OF MINING.
is dependent upon the Jifference of area between the back and
front of the piston. On its way down it soon cuts ofl the
equilibrium-passage and the air can only enter at the inlet ; the
steam operates by expansion for a short space, till the piston
has passed and uncovered the exhaust-port, when a discharge
takes place as the blow is being struck. One fact is noticeable,
that the amount of steam used is only that necessary for the
down stroke ; for that used to raise the drill escapes by the
equilibrium-passage to the top."
87. The drill-tool is of steel, with an X, I, Z or S cutter,
the first three forms being more common, because more rapidly
dressed to a shape ; but they must be very regularly turned, or
the hole will be " rifled " (cut triangularly instead of circularly).
The S is the surest for a round hole. If there should be a
tendency to rifling, try a change in the form of the bit. Each
bit is of specific value. The flat cuts homogeneous rock well,
but will not stand long. In sandstone, the bit should be bluff,
and in some silicious rocks even have a slightly flattened edge,
a " stub." For rocks that do not crush, but chip, a sharp edge
will be needed. The steel used is from |" to \\" diameter,
according to the percussion to be imparted to the rock. The
smallest is for a 2", and the largest mentioned for a 5" piston,
corresponding to a blow of about 200 lbs. and 1200 lbs. respec-
tively. The drill steel is obtained in sets graded according to
the amount of the feed of the drill with which they are to be
used. Each bit has a life of about 275 feet of holes, of mod-
erate depth each, provided the machine is not too powerful to
handle long steel. The average mining size is the 3" piston,
with a I J" to i" steel, feeding 20" to 24", and having 8 pieces
to the set ; the longest for a hole of about 10 feet. Ordinarily,
a bit will drill 3" before requiring sharpening; and in chang-
ing the tool care should be taken that the follower has an
€dge narrower by ■^-^" to \" than the one withdrawn.
The shank of the drill steel is inserted into the enlarged end
of the piston-rod and clasped by a split-chuck lock-ring (Fig.
234), or it is keyed or bolted.
The rotation of the drill through a small arc, each stroke, is
DRILLS AND DRILLING 461
accomplished by about the same apphance in all patterns, —
a fluted bar and nut constituting a rachet. The rotation must be
perfectly regular, to prevent rifling. The Burleigh has a
spiral feather on the piston-rod, recessed into a groove-piece
in the cylinder-head. It is toothed and held by a detent,
which permits it to turn on the forward stroke, but prevents
turning during the up stroke of the engine. In the IngersoU,
a grooved bar fitting into the back of the piston turns it on
the back stroke, and is itself allowed to rotate on the down
stroke (Fig. 238). The Dar-
lington device is like the
Burleigh. It turns the piston
and drill on the up stroke,
and itself turns during the
down stroke. In the Schram,
an auxiliary piston turns the
drill.
In whatever the pattern, the cylinder and its tool slides in
a guide-way which, being rigidly mounted, carries the drill-
point forward more or less rapidly as the cutting is fast or
slow. This must be done simply, and may be b)' hand or
automatically. For mining purposes, and whenever the small
sizes of drills are employed, an automatic feed is of little value,
and a man is employed instead. Irregularity in the nature of
the rock implies a varj-ing rate of penetration, and, hence, a
variable feed. If a fissured rock or cavity is encountered, the
drill would suddenly give way, and the uncompromising regu-
larity of the blow would result disastrously. Only a prescient
feed would obviate this liability to excessive stroke. In the
larger sizes of drills the piston strikes a knuckle-joint at the
bottom of the cylinder and revolves a nut that feeds the drill
to its work. This saves one man as each machine would
otherwise require two.
The percussive effect improves as the full steam pressure is.
obtained at the moment of the blow ; and what is called a per-
fectly " dead blow " is highly desirable ; but it is inadvisable,
on account of the shock to the machine and the consequent re-
462
MANUAL OF MINING.
purs. The piston is, therefore, caused to terminate its stroke
on elastic buffers, or against an air-cushion in the clearance-
space. The latter consumes motor fluid, but is less expensive
than the repairs due to a dead blow. In several forms of drills
the piston is cushioned by the exhaust, instead of live air, as is
the case with the plain slide-valve patterns.
A rigid support is an essential adjunct to the drill, and
several types of mountings are provided, each having a special
end in view, though a machine can be shifted from one style
to another. In tunnels and shafts where the ranges of holes
have approximately parallel directions, it is clamped to a
stout hollow cylindrical column (Fig. 239), or upon a project-
J-L
ni.
Fig. 239.
ing arm, as in Fig 226, which admits of drilling several holes
from one position of support. The arm on the bar gives an
eccentric range to the drill. Jack-screws at one end clamp
the column, which terminates in claws that bear into blocks
resting on the rock. These can be had 6, 8, or 10 feet long,
weighing about 30 lbs. per foot, at $60 to $90.
The tripod form is the more advantageous support for sur-
face or for stope work, where it is expected to be an acrobat
DRILLS AA'D DRILLING.
463
^Fig. 240). It should have a universal joint, be strong, and
easily set. Each leg rests in a moiled-out hole.
This machine, as described, has no intricate mechanism to
watch and manipulate, and should operate from the " go."
Steam gives a little trouble in starting, because of the unequal
heating of the parts, but, by proper throttling, injury is avoided.
The drill should always be started on a square face. Glancing
blows are ruinous. Holes should be started at short, light
Fig. 240.
strokes ; the short stroke is obtained by feeding the cylinder
close toward the rock.
It is admitted on all hands now that the power-drill has
passed its tentative stage, and can do more work with the
consumption of less powder, steel, and smithing than can
hand-work, and in anyplace that can accommodate a "double-
hand " gang. One would not undertake to discuss the com-
parative excellences of the different drills on the market.
There are several styles, doing all manner of work at shafting,
tunnelling, and stoping ; Figs. 239 and 240 illustrate the manner
of their use. Personal observation among, and discussion with,
operators in various districts fail to reveal any formula by
which the makes m?y be gauged. In one camp the Rand, in
464
MANUAL OF MINING.
another the Rand, Waring, and National, are indiscriminately
used ; still another prefers the Burleigh ; while in others out
here the Ingersoll excludes all others. One region prefers
the " Little Giant," and another mine will discard it for the
" Slugger ;" in like manner preferences are displayed for the
"Eclipse" or the "Sergeant." They are all highly com-
mended, and their employment in a particular locality may be
a matter of accident or of natural selection, the rock happen-
ing to be most suitable to the given form which has then
survived the periods of test.
Certain it is that the author's experience favors the fluid-
moved valve-drill for hard rock, the Slugger and Sergeant
being adapted to our Rocky Mountain material ; but whether
or not they are under all circumstances the best, one would not
dare to aver. Each miner must determine, from the nature of
his rock, the proper air-pressure, rate of speed, and proportion
of rotary motion required for the most effect. The manufac-
turers can give great assistance in this regard.
The comparative tests announced by different makers are
of too short a duration, and are conducted under conditions
too limited to avail the engineer. As a matter of fact, it
becomes a question of the survival of the
fittest, and that is determined by the
success with which the essential attributes
are supplied. A stated air-pressure will
accomplish a certain penetration in an
ideal drill, but the various patterns will
approach this amount more or less satis-
factorily as the frictional resistances are
less, if the blow is uncushioned, and if the
reversing-valve is perfectly accurate.
Of course, the heavier the impact, the
greater the effect ; but the blow is de-
pendent upon the pressure and the drill
weight. For hard rock, therefore, either
the pressure should be high or the mov-
ing mass large. The former is inexpedient for economical rea-
sons explained in No. 93, so a heavy striking mass is imperative.
Fig. 241.
DRILLS AND DRILLING. 465
On the other hand, power-drills should be portable, necessitat-
ing a light frame and guide. A high piston-speed may be
desirable and advantageous, but the kinematic difficulties
render it unadvisable.
Besides these qualities, however, are those which never
figure in the comparative tests, so called, the convenience in
handling, and true automatic rotary and feed appliances. If a
machine is capable of a variable stroke, so as to start the hole
on a light, short stroke, and will "mud" well, it meets two
very important features that are not always possessed. A
long stroke conduces to quick mudding.
In remote camps the dominant attribute is a simplicity of
parts to assure a "lasting-capacity" as well as a "boring-
capacity." The early pattern is said to have had 80 pieces in
it, and its repairs were so numerous that each drill was built
over every two years, and it re uired five machines to keep one
going. Now continuous ^\'ork is maintained with one drill in
the shop wliile two are working, its average life being 8 shifts,
corresponding to about 400 lineal feet of holes. In a certain
Lake Superior copper-mine the cost of blacksmithing is about
64 cents per drill per 24 hours. The amount and cost of
breakages are too variable for any precise estimate. A mine
employing 22 drills constantly allows for $60 annual repairs per
drill. These two items, amounting daily to 85 cents per ma-
chine, may seem an unfavorable comparison with hand labor,
where 55 cents was the allowance per daily gang ; but a reduc-
tion to the relative progress will prove more equable.
A recital of a few of the comparative tests may be of
interest. About Silverton, where 7 inches of hole will dull 14
to 20 drills, a machine cut 2 feet, the length of its lead, in 12
minutes. Three men will drill three 30-inch holes in 10 hours,
while a machine does seven holes of 5^ feet each. An average
of nine neighboring mines, in the conglomerate, showed machine
drifting and stoping to be, respectively, 22 and 36 per cent
cheaper than hand, and sinking 4 per cent dearer, with a prog-
ress 60, 54, and 38 per cent more rapid, the latter gain in sinking
compensating for its increased expense. In the iron-mines,
machine lab.jr is one fourth as expensive as manual. Three
/
466 MANUAL OF MINING.
men on a 6 x i6 shaft did 0.37 feet daily, while two machines-
advanced 3.4. H. S. Drinker, " Explosive Compounds," quotes
an average daily progress by hand and black powder, in 21
tunnels driven in solid hard rock, of 1.441' in heading, and 1.96'
in the bench ; and of 58 tunnels in easier rock, 2.55' and 2.62',
respectively. With machines and nitro-glycerine the progress
was five to seven times as fast. The recently completed
Cascade Tunnel made 2 lineal feet per 24 hours with 17 men
on the heading, and 6.9 feet with 5 machines.
An eleven-months comparison of hand, Schram percussion-
drill, and Brandt's rotary drill, gives an efificiency as to speed
of I :4.73 • ^'^'^ 5-26, relatively ; and as to cost, i :o.62 ; and 0.60.
The consumption of fuel and air per drill may be calculated
as in any ordinary steam-engine. The cost of the ordinary
mining-drill is about $325, and of a complete plant of 6 drills,
with a 16 X 24 compressor, etc., is $7000. A smaller outfit
for 3 drills was recently delivered in Denver for $3700.
There are several patterns of percussion-drills operated by
electricity, but the results give as yet insufficient proof of its
value for reciprocating machinery. In Fig. 241 is shown the
Edison drill.
The average depth of holes in tunnels rarely exceeds
twelve feet; in stopes and narrow work, four feet. A ver)?
deep penetration cannot be obtained; the impact of the blow
would be destructive to a long line of rods, and the drawback
power of the piston is small.
88. M. Leschot has the credit of the first application to the
miner's art of rotary diamond-drills, which have since steadily
gained in favor and increased in range of utilit}'. Several
diamonds are forced into sockets on the end of a steel tube,
and on a rapid rotation abrade the rock. The cutter-face is
entirely covered with diamonds in such manner that no con-
centric circle fails to touch one, and one or more projects
transversely beyond the tube. The bit may be annular (Fig.
242) or solid convex or concave face (Figs. 241 and 244).
The first is more commonly used, as by that means a cen-
tral core of rock is uncut, and maj? subsequentl)^ be with-
drawn for inspection. The debris is carried away by means
DRILLS AXL> DRILLING.
467
of a stream of water passing down inside of the tubes, washing
the drill-face and carrying the cuttings up outside. The solid-
head bits are preferred for mere drilling, except for large holes,
the concave surface being better than the convex. The wash
water escapes through the holes in the face.
The diamonds used on the face are of the black or deep
red variety ; on the outer edges, borts ( imperfect diamonds).
" Theoretically, too many carbons cannot be put in ; there should
be never less than 12," and as many as 20 may be mounted
on a bit. Recesses are accurately prepared for them, into
which they are set and secured b)' metal hammered up around
them. In some cases a firm setting is obtained by forcing the
stones forward through small holes in the metal b\' means of a
screw, or by hydraulic pressure. A later method consists in
forcing the stones nearly through the metal, and subsequently-
grinding the steel down until the stones are exposed. The bit
is coupled to the tube, which is added in 8-foot lengths as the
hole deepens. The diameter of the hole is a matter of indif-
ference where prospecting or the long-hole drilling is intended.
Those of ordinary depth are up to 3 inches
diameter, and those of great depth taper from 5
inches down. The tubes are of slightly smaller
diameter, if inch tube is used in \\ hole, and
weighs 3.4 lbs. per foot. Figs. 245 and 247 show
the guide, which is just the size of the hole, and
maintains the bit in the direction in which it
started ; the spiral grooves allow the water to
escape.
At the upper end of the drill rod is a joint or
swivel, through which the supply of water is forced by means
Fig. 245.
468
MANUAL OF MININC.
of a pump. Above is the connec-
tion with a rotary and feed motor
operated by a steam-engine, the ca-
pacity of which varies with the
amount and size of drill-tube to be
manipulated. An 8-horse-po\ver en-
gine is suitable for a looo-foot bore-
hole. The running-gear should be
firmly framed and supported, that
the weight of a great line of rods
may be easily handled; looo feet
will weigh from 4500 to 6000 lbs.
A very light temporary shed will suf-
fice for cover.
Two methods avoiding a positive
feed are in vogue for driving: one,
a spur-wheel feed ; the other, the
hydraulic. The former is so adjusted
by differential gear that its friction
shall equal a desired resistance ; and
when this is exceeded, because of
undue strain below, a regulation is
obtained. Stratified rock changes
so much and so rapidly in structure
that a uniform feed is impracticable
in deep holes, and inferior to the
hydraulic feed, of which Fig. 246 is
a section. It is a simple motor,
which by means of hydraulic pres-
sure on the piston produces a
pressure which is maintained con-
stant. Both ends of the cylinder
are connected with the pump, and
suitable cocks admit of a perfect
control by the operator, who gives
any variation or reversal of speed
within the limit of the pump and
piston-area. Gauges indicate the
-T
Fig, J46.
DRILLS AND DRILLING
469
pressure. Only the hardness of the rock determines the rate
of feed, and this rational system saves all parts of the machine
from danger of breakage. Fig. 247 shows the feed-cylinder as
the extension of the drill-tubes. The connection between the
tube and the feed is by some form of chuck, which may be
Ftg 247.
loosened at the end of the feed-stroke and run up to the top
for a new grip.
The pressure exerted by the feed is just sufficient to pro-
duce abrasion, not to cut the rock. The tube is partially sus-
pended by friction-rollers at the surface, so that it is subjected
470
MANUAL OF MINING.
to very little tension. The power producing rotation must be
less than the torsional strength of the rods. This would place
a limit on the possible depth of explorations, while the regu-
lating power of the feed limits the capacit}' of the machine.
In addition to the integral parts mentioned, a steam-engine,
gear, and hoisting-drum are compacted upon a rigid mounting,
varied with the purpose of the borer. It may be bolted to a
heavy frame bed placed on wheels, with portable boiler, or
mounted as in Fig. 247 for underground work. One foim is
Fig. 248.
of gun-metal and steel, and weighs only 400 lbs., yet can bore
150 feet with ease. The drum is added for hoisting the drill-
tube without altering the position of the machine, which remains
in place till the bore is completed. A high derrick facilitates
the addition or disjointing of tubes.
The rate of revolution of the tube and its bit is from 400 to
800 per minute, and the progress is remarkably fast, averaging
a penetration of 13 inches to 2 feet per hour, stops inclusive.
The drill bores only about one half the time. The use of the
annular bit does not increase the speed, for the rods must be
raised every 10 to 15 feet of advance to examine the core,
which is broken from its place by the core-lifter (Fig. 249), and
raised with the tube. In uniform rock the tool
need not be raised as frequently as in strata of
varying texture. Should the hole ha\'e penetrated
a soft layer between two hard ones, the core would
twist off and grind it away, and its existence '^"^ '•"'
would not be made known in the core. Again, the tendency
of the core to turn in its tube would give false information as
to the dip of the strata. For this reason, also, a flat, not round,
hoisting-rope should be used. At best the core is only a par-
tial guide. A slime-box receiving the cuttings would indicate
the presence of the soft rock, but many causes combine to make
even this examination unreliable. A careful measurement, an
DRILLS AND DRILLING.
4/1
allowance for wear, and frequent raisings are the only checks.
Shales and clay slates give smooth sailing, but fire-clay chokes
the barrel. In such cases the full pressure of the pump will usu-
all)' wash it out ; if not, the tube must be lifted. With holes of
a moderate diameter there is no necessity for tubing the hole.
Accidents are rare. A diamond may fall out, and, if it can-
not be recovered, must be chopped up at once, or the water
supply must be reversed to wash the stone up the tube. A
chopping-bit is used to break up hard nodules or boulders.
89. Holes may be bored in any direction, though the
machine is best adapted to vertical ones. Fig. 247 shows the
472
MANUAL OF MINING.
machine drilling at an angle; the "Little Beauty" (Fig. 250)
drills 70 feet horizontally without trouble. The friction of
the tube on the rock limits the length of flat hole that may
be drilled.
In Fig. 251 are exhibited explorations in the Silver I.-l: '
mine by the use of an underground machine. For prospecting
territory, for drilling a deep sump-hole to drain a mine, for
rapidly sinking a connection through which to pump out a
drowned mine, to sink a tail-rope bore-hole, etc., the utility of
the diamond drill is generally recognized. The Poetsch method
(p. 253) depends upon it, and the long-hole process is possible
only by the use of it. It is suitable in hard or the hardest
DRILLS AND DRILLING. 473
rocks, and, remarkably enough, will perform in granite better
than in soft stone, according to the report of the Superintendent
of the Hope Mining Co. Doubtless many properties owe their
existence to the result of diamond-drill discoveries, and its use
has frequently saved expense in various ways. But it is not
considered infallible in its indications as to the presence or
absence of the ore body sought. Though it is true that tun-
nels have been carried by the long-hole process at home and
abroad, the percussion-drill is cheaper in tunnel and for short
holes. The cost of drilling varies materially. An average of
29 2-inch holes, 400 feet each, was $2.35 per foot in a Lake
Superior iron-mine ; 16 holes, aggregating 5877 feet, cost $1.97
in the Pennsylvania coal measures; and 24 holes, averaging
18.9 feet per shift, with a total of 9902 feet, cost $2.22 per foot.
In the Mariposa estate, the cost of prospecting holes 74 to
231 feet deep, in 34 to 146 hours, averaged $1.10 per foot,
including diamonds ($0.32). The actual drilling time was
about one half the total.
There is a great difference in the item charged to wear and
tear of the diamonds, varying from 21 cents to 56 cents per foot.
Experience has determined that the diamond is practically use-
less after 6 settings. Manufacturers say that there is a remark-
able difference in the qualit}', hence in the wear of the stones.
The borts and black stones are tougher than the vitreous.
The item does not refer so much to the wear of the stones —
as that has been found to be inappreciable after drilling 400
feet, but rather to the loss due to the falling of the stones out
of their sockets. Ground charged with pyrites is especially
bad, causing the stones to crumble.
Comparing it with other methods, the diamond drill is
rarely cheaper in deep soft rock than the Mather and Piatt
system (p. 397); in hard rock it supersedes all others, except
where water is very scarce. Tubing in conjunction with it is
troublesome, if not out of question, for deep holes, and reaming
is not easily done.
Cost of drill and outfit for lOOO feet of 2" rods, $3872,
Two drills require 5 men.
474 MANUAL OF MIXIXG.
For underground work a 3-horse-power electric motor is
"mounted on a truck, with drum, drill, and pump, and permits
core-drilling to advantage in small spaces. In many mines 1"
-cores in sections of 5" to 20" are cut for 80 feet depth, and a
great deal of prospect'ing has been prosecuted with this com-
pact machine, which makes 1.60 feet per hour at a cost of 68
cents to $1.03 a foot. Fred. G. Bulkley, of Aspen, Colo., has
devised a graphic representation of the results of borings by
plotting them to scale on a cross-section paper, which picto-
rially conveys the information as to seams, faults, etc.
Rotary perforators for tunneling-out the full area of head-
ings and entries are offered on the market. At one operation
a series of cutters on a rotating boring-head grinds away the
whole face for a core from the heading some 7 feet in diameter.
One was used in the Mersey subaqueous tunnel. It travelled
at the rate of 39" per hour, and executed its work satisfactorily
in the argillaceous chalk.
Brandt's borer, which is highly esteemed in Prussia, is a
hollow cylindrical steel bar, on the end of which are formed
five teeth. Rotated by a pair of small hydraulic engines, it is
forced against the face of the rock, and cuts a hole the core of
which is cleared away by the continuous stream of water es-
caping from the driving-cylinders.
90. Since the advances made in the manufacture and use
of the machine-drill, the systems of drilling and of blasting have
had to undergo corresponding changes. In hand-work, the
object sought is as much to secure a good bench for the next
shot as to break ground with the present. With simultaneous
shooting, and particularly in tight ground (on faces of drifts
or shafts), all of the holes are drilled more or less axially, and
the blasting operations are conducted differentl)', because the
inconvenience of handling machines supersedes the gain from,
attention to the lines of least resistance, and it is not always
possible to drill holes with the machine in such a way as to
conform to the fundamental principles.
According to the mode of arranging holes, we have three
systems. The first was employed with the earliest experi-
DRILLS AND DRILLING.
475
mental work on the pioneer machines at Mont Ccnis and St.
Gothard tunnels. Eight perforators were mounted on a car-
riage, and bored holes at different angles covering an area of
250 square feet. When the requisite number of holes was
drilled, the machine was shifted to another space, where it
4/6 MANUAL OF MIXING.
repeated the pe-'formance. It was run away when the firing
was to be done. A centre hole was surrounded by a ring of
eight rupturing-holes, outside of which were 3 full and 2 seg-
mental concentric rings of holes. These were fired in volleys
after the first central set. With 18 holes of 3 feet to 5 feet
each, charged with if lbs. dynamite, the progress averaged 18
feet a day through schists and gneiss.
The second system is very popular, and known as the
'centre-cut," which was introduced in the Musconetcong
Tunnel, increasing the progress from 89 feet to 116 feet per
month. The American method of tunnelling was in process
(see Figs. 201 and 254, and p. 388). The face of the heading
was 8 feet high by 26 feet wide, and had six machines operating
on it, drilling 36 holes of \\" to 2J" diameter. The holes are
drilled in vertical rows of four each, and a depth according to
the location. The two central rows " look toward " each other,
and meet at the bottom (Fig. 252). The next two rows on each
side of the axis also point inward, but less so than the central
or cutting rows ; while the outside rows are parallel to the
axis, or incline slightly outward. Roof holes and corner
squaring-up holes complete the drilling, and should trim up
the profile of the tunnel at once. The positions of these holes
are variable. In very hard rock the holes of the two central
rows are in pairs close together ; sometimes they are single, but
large, 4" diameter. In firing the two central rows (i, i. Fig.
253), first break out an entering wedge, — not to the bottom of
the holes,- — which facilitates the work of the next two rows (2, 2),
which shoot toward the walls, after which the advance is squared
up. The breaking-in is done with electricity, but the enlarge-
ment and squaring-up is done by fuse and a lower grade of
explosive.
The depth of the holes and their distance apart depend
upon the rock and the advance desired. Advances of 14 feet
have been made, but there is a limit to the capacity e\'en of nitro.
glycerine, and 10 feet is quite sufficient. To secure this, clean
the two central rows of holes are \o\ feet deep, the remainder
12 feet, except the six roof-holes of 8 feet each. In a narrower
DRILLS AND DRILLING.
477
tunnel of say 1 1 to i6 feet wide, an 8-foot advance will suffice.
Four machines can easily operate in a double-track (27 feet)
tunnel — six can be arranged by placing two on each of the two
central columns. Three machines in a single-track tunnel, and
two in an ii-foot heading, will give progress as rapid as the
shovellers can handle the dirt. Out of an average 8-hour shift
the actual drilling heat is about 5-2- hours ; the shifting of tools,
Fig. 253
etc., takes |- hour; loading and blasting and removing rock,
about an hour each.
As illustrations of progress we have : the heading of the
Haverstraw Tunnel, 9X 16, requiring 20 holes of about 8.4 feet
each, was completed in 20 hours; weekly progress in 8x27
South Penn Tunnel, 74 feet of sandstone; two machines in
Washington Tunnel, 7^X11, progressed 8.26 feet per day in
solid rock, with 26 holes of about 10 feet ; the Cascade Tunnel,
16 feet wide by 22 feet high, progress 200 feet per month, with
two faces of attack, 20 to 23 holes 12 feet deep, by 5 machines;
in medium hard basaltic rock, average 6.9 feet per 24 hours;
four machines in the Vosburg heading, 8 X 27, made the advance
478
MANUAL OF MINING.
in 10 hours, with 26 holes (8 centre and 18 sides); in the D. &
R. G. R. R. Tunnel, two machines made a complete drilling:
round of 20 holes, 9 feet deep, in 7 hours ; the aggregate depth
of the 36 holes in the Musconetcong Tunnel was 408 lineal feet,
the firing of which gave nearly 10 feet advance ; one shift drilled
and broke a cut or a side round with six macliines.
The consumption of powder varies. 7 lbs. of Giant No 2
was used in the centre cut of the Washington Tunnel 5^,- for
each side round hole ; the Musconetcong consumed 0.4 lb of
nitro-glycerine, and 4 lbs. of Giant No. 2 per cu. yd. broken ■
on the Mariposa estate, in very tough rock, 7 lbs. of Hercules
No. I and 10 lbs. of No. 2 per hneal foot of drift ; in the
Vosburg, 100 to 120 lbs. of Rackarock per advance.
The bench of the tunnels is attached in one (Fit^. 25^) or
two (Fig. 254) sections, A and B\ two wall holes, one or two
DRILLS AND D K 1 1. LI .\ t: ■ AT^
transverse rows of 4 top holes downward, and half a dozen
bottom holes, lift each bench with every other shift. Fifty-
four feet a week is the record on a very hard sandstone bench,
14 X 27. This work is not only more rapidly accomplished,
but also with a powder consumption per cu. yd. of rock of about
one half that in the heading.
91. Brain's radial system is employed in headings too small
for more than one machine, and, like the "centre cut," is
equally applicable to shafts. The design is to drill all the
holes from one position of the machine, and thus minimize the
time lost in shifting. The holes are shallow and \'ary greatly
in length, those making the smallest angle with the face being
the longest. Four ranges of holes are drilled, and in a certain
case the machine, from a position 4' 8" from the bottom, 2'
from the top, and 2' 6" back from the face, put 29 Jioles w ith
a total length 70', advancing 3' with an average of 2.4 cu. ft.
broken rock per lineal foot of hole. Sometimes a few e.vtra
squaring-up and lifting-holes are necessary to trim the per-
iphery of the drift, but, ordinarily, the firing of the most ang-
ling holes first breaks out the rock to daylight and opens a
face for the other successive rounds. The advance cannot be
large, for neither deep nor angling holes are possible in a nar-
row drift. In a drift 8' wide, two settings of the machine are
sometimes made drilling from, near each wall, and thus forming
a modified centre-cut plan. In some mines a practice pre\'ails
of cutting a horizontal range of bottom holes, two ranges of
holes looking downward, and a top row to break out horizontal
instead of vertical wedges ; this plan requires a bar-mounting
for the drill, and a drift say 7x8 feet.
Gen. Henry Pleasant's method of shaft-sinking is a novel
and eminently successful application of the diamond drill.
One or more diamond drilling-machines are set up over the
site of the shaft, and bore vertical holes as deep as the shaft is
to be carried. The machines are moved to new positions and
additional long holes bored. The operation is continued until
the entire area of the shaft is pierced by holes at suitable dis-
tances apart. The St. Clair shaft of the Reading Coal Co,
480 MANUAL OF MIiVlNG.
had 35 holes drilled to a depth of 200 feet; 25 holes covered
the space 13' 10" X 16' of the Norwegian Colliery shaft. An
average of three machines in six weeks bored 35 holes through
300 feet of hard rock over an area of 25' 8" X 13' 10".
When the " continuous process " is completed, the machines
are removed for the blasting. The holes are filled with sand
or water for the full length, except in the upper 3 or 4 feet,
which are treated like short holes, charged with dualin and
fired, — the central ones first. When the debris has been cleared
away, the shaft will have advanced 3 or 4 feet. A few feet
more of each hole are cleaned out (sometimes the bottom
plugged with clay), loaded and fired. Thus each section ad-
vances with an alternation of shooting and hoisting. Herein
lies the secret of the success of the method. The operation of
boring is continuous to the end, and the other operations may
■be uninterruptedly prosecuted. Though it is not always
cheaper per cubic feet, it effects a great saving in time, and
quick access underground may prove the element essential
to the success of the undertaking.
92. The undermining of coal is accomplished by ma-
chinery of two types, one dependent upon abrasion produced
by a saw and chisel cutter, the other upon percussion. Of
the first variety there are three general classes of machines
using either a rotary bar, a rotary wheel, or a chain. The
motor power for any of these types is electricity or air. The
competitions in the coal trade have prompted many an
engineer to turn his attention to the direction of an appliance
which might, in some degree, tend to decrease the cost of
production without in any way increasing the risk to life or
property. These machines, of whatever type, it must be
admitted, do the work of undercutting the coal to a moderate
depth in a narrow groove as expeditiously as can be done by
manual labor, removing therefrom the severer forms of the
miner's toil, and rendering his occupation less laborious. The
manual effort of the digger, exerted under the unfavorable
conditions in a constrained attitude, is most wastefully
applied, with the production of an excessive amount of waste
DRILLS AND DRILLING. 48I
dust and small eoal, and thus affects seriously the output of
the mine.
The machine which is to replace manual labor must
occupy little room, be low and light, capable of being handled
by two men, and of a size small enough to admit of working
around and between the props. It should be capable of
starting in the corner of a pillar or loose end, and of cutting
clean to the walls of the room, right handed or left handed,
and to any height. It should be equally suitable for a ver-
tical shearing of the coal, as well as for holing. During the
year 1896, over fourteen per cent of the total bituminous coal
tonna^"e was mined by machines in eighteen states of the
Union. The U. S. Geological Survey announced the use of
1139 machines in 115 mines in fifteen states; but with the
addition of other known cases, the aggregate number in use
jnay be safely placed at 11 50 machines in 120 mines produc-
ing [2,000,000 tons of coal. During 1891, the machine
output was but 3.27 per cent of the total.
The machine does not dispense with the lab®r of the
miner: it only more efficiently accomplishes the most arduous
part of his work. The chief value of the change lies in the
subdivision of the labor formerly imposed upon one man, and
the consequent celerity and safety resulting from the atten-
tion of each man to his own branch of the work.
In Illinois the Legg machine is used in driving the rooms;
elsewhere, the Harrison, Jeffrey, Yock, Lechner, and Sergeant.
The Lincke is used to some extent in the Avestern country;
the Marshall and Frith is the old-style machine still in vogue
in Europe.
The rotary or chisel-cutters are always accompanied by a
positive feed which advances the machine ; in this class are
the Lechner, Jeffrey, Marshall, Hurd and Simpson, Baird and
Lincke. In the percussion class are included the Frith, Har-
rison, and Sergeant, each of which, except the Frith, must be
moved after the bearing under hole has been drilled. The
Harrison machine is the most popular in Ohio and Illin(}is,
and is illustrated in the accompanying cut (Fig. 255), which
requires no explanation.
482 MANUAL 0/< MINING.
The valve-motor is a single-cam rotary device. It; is
compact, light, and will " bear in" about 80 lineal feet of 31-
foot holes in ten hours, allowing two hours lost in changing
bits and positions. In twenty minutes it will cut along the face
to the width of its board. 10 cu. ft. of 70 Ibs.-air, at a rate of
200 blows per minute, is the average consumption. The several
sizes of machines differ only in power and depth of groove.
The kit of tools (three pairs of augers 2', 4', and 6' long,
and one pair of 18" extenders) is dulled every day, and refaced,
by the blacksmith. Each bit is refiled by the blaster after use.
With two machine-men, it employs five loaders and a blaster.
The Sergeant rock-drill has been adapted also to coal-mining,
and gives eminent satisfaction in the South.
Frith's machine imitates the miner, working a 75-lb. pick
by bell-crank lever. At a rate of 70 blows per minute, 11
square yards of a 2" groove are cut 42" deep per hour. The
simplicity of these patterns enables them to be readily handled
in thin seams.
The other class of machine is represented by the Jeffrey air
and electric, of which the latter style is shown (Fig. 256).
In 6 minutes it will cut a groove 39" wide to full depth ;
can be reset to position in 9 minutes, and moved into an ad-
joining room in 20 or 30. It therefore undercuts a room in
about 2 h. 10 min. ; 60 amperes at 250 volts will operate it. It
occupies an area of 2' X 7' 6" and weighs a ton.
The Lincke cutter is a revolving axle 3' long, like the
Jeffrey, and gives nearly equal satisfaction. The Lechner is
similar.
The Winstanley is a rotary toothed disc capable of being
turned under the carriage or out against the face, revolved by
two oscillating cylinders working at a pressure of 30 lbs., and
cuts 70 square feet per hour. It is mounted on a carriage
moving along a track longitudinal with the coal-face ; and
weighs 1500 lbs.
A chain carrying several chisel cutters is the device in Mar-
shall and Garret's machine on wheels. It is braced to the roof,
and the cutters are so set that they carry the scrapings out-
\ n :f
\' -r
o
3 I
484 MANUAL OF MINING.
wards. This has the advantage of keeping the machine to
the coal. Another Marshall design, also hydraulic, "cuts
into coal like a scoop into cheese."
The Jeffrey endless chain or belt carrying a number of
cutting knives and travelling horizontally about the frame of
the machine is very much used, and has largely supplemented
the rotary bar type. The action of the bar is somewhat
similar to the cross-cut saw, because it cuts the coal across the
grain, and not with it. The machine with the bar in front,
Fig. 229, can be used conveniently only in headings, as it
requires so much free space between the coal-breast and the
timbers, for use in mines working by the long-wall method,
the bar of the machine projects at right angles from the frame
and because it is in closer contact with its work exerts a
greater force than does the rotary-wheel which is frequently
used. Both classes of bar machines have a great disadvantage
in the tendency " to climb in the coal." The rotary- wheel
machines and the chain-cutters act m-ore like rip-saws, cutting
along the grain, and not across it. The rotary-wheel machine,
however, has a disadvantage during transportation, in occupy-
ing so great a space. If the wheel could be made in halves,
fastened together by bolts easily removed, the machine would
be far more acceptable in small rooms. The machines, when
properly adapted, appear to work with equal facility in rooms
or on long-wall in thick or thin seams, but the pillars are not
yet as economically robbed as by hand. Coal containing
much pyrites and bony nodules gives special difificulty to
machines of the rotary bar type, but is not so great an annoy-
ance to machines which distribute the wear and tear over all
the cutting parts equally, as in the case of the rotary-wheel or
the chain.
Chief Inspector of Mines for Ohio, R. M. Haseltine,
reports the result of a series of investigations upon electric
coal-cutting machines in the bituminous mines of Ohio, in the
course of which he states that few coal-seams are adapted to
machine-mining at all; and in a still smaller number can the
present type of standard machine be used with economy.
DRILLS AND DRILLING. 485
For profitable mining the roof must be strong and free from
slips or bell-shaped balls; especially is this true when the
props are set more than twelve feet from the face to accommo-
date the electric cutters. The floor of the coal face must be
nearly, if not quite, level to admit of the successful work of
machines. The thickness of the face has been considered as
the index by which its adaptability for introduction is to be
determined; and, with but few exceptions, no attempt at an
installation has been made except in the very thickest of faces,
for which machines builders have designed. The weight of
the machine for the thin vein must be as great as for a thick
one, if the coal fibre in each is equally firm.
In measuring the horse-power which was necessary to drive
these machines, an electric current was opened near the
machine, and meters registering potential and current were
inserted , as a result it was found that the bar machine con-
sumed from 16.5 to 22.7 horse-power, while chain machines
required from 8.6 to 18.1 horse-power. If the number of
cuts is taken into consideration, it is found that the average
horse-power required by the bar machine is 1S.7, by the chain
machine 14.4. The chain machine was found also to con-
sume less power for its own driving. The relative efficiencies
of the several machines in horse-power required to undercut
one square foot of coal in one minute, was, for a chain 4.2,
and in the bar machine, which makes a misapplication of its
power, 8.9.
The introduction of a properly selected cutter always
results favorably, though some mines have abandoned ihem
for causes not pertinent to their economy. The men do not
take kindly to them; but their efficiency is undoubted.
Though the number of mines using coal-cutting machines
exclusively in Illinois has decreased slightly between the
years 1888 and 1895, the number of machines remains about
the same, and the percentage of total coal output the same.
A few additional mines have introduced machines during 1 895 .
Naturally its most general application will be in hard mining
coal, which cannot be blasted " off the solid " as is soft coal.
4S6 MANUAL OF MINING.
Many of these machines can shear the coal as well as under-
cut. As all entry and narrow work requires shearing before
breaking down, it is evident that the scrapers and planers
have a decided advantage over the percussion-machines; but
even they are not as economical as hand-drills. The latter
progress faster, and prepare the face for the other operations
quicker than do power-drills. The hand-working miner can
shift his place of working from one narrow place or bench to
another more readily than can the machine-cuttef.
Any machine will cut 1 3 square feet in, say, 10 minutes, or
a 20' room in less than 2 hours. Making a liberal allowance of
30 minutes for shifting, 4 rooms are underholed in a day with
the employment of 2 men. This in a standard vein (4' thick)
corresponds to 45 long tons, or at least to 7 men's kirving.
As a matter of fact, the output is more nearly 70 tons per \o
hours. On this, with 2 men to a face, 1 1 rooms would have
to be kept open to equal the supply of one machine. A mine
producing lOOO tons of screened coal (1300 tons of " run of
mine ") could obtain it from 28 machine-rooms, or "jj hand-
rooms. The operations are therefore more concentrated, —
less territory has to be kept open than in hand-work; and
this is an important feature, recommending the " iron man."
In the comparative cost of coal produced by the percus-
sion-machines and that by the rotary-bar or chain per ton
of run of mine coal on the 60-foot scale, it was found that a
ton of run of mine, exclusive of power, costs 27.7 c, while a
ton produced by pick-mining costs 39 c. ; by the rotary-bar
and chain machine, exclusive of power, the cost per ton was
29.7 c. as against 39.6 c. in the same mine, produced by pick-
mining. Though this comparison indicates the apparent
advantage in the use of projectile machines, it will be largely
reduced when the number of tons which each type of machine
produced daily is taken into consideration. The amount of
slack, dirt, sulphur, etc., which is allowed for in machine-
mining is, as a rule, 30 per cent, and on this basis machine
coal costs 10 c. less per ton than hand-mined coal. The
amount of lump coal produced per ton of run of mine is fully
DRILLS AND DRILLING. A'^7
6 per cent greater in machine than in hand mined coal. Its
groove is only 2j", as against an average of 6" for even the
skilful miner, whose kirv is 9" high at the face and 2" at the
rear. Over 3 cubic feet of coal is thus gained by the machine
per yard of face, with less waste and more large coal. The
ratio of slack produced by machine and by hand is jL to \.
The per-ton amount of powder consumed in 30 machine-
mines is less than that consumed in 503 hand-mines during
1895 in Illinois, in the ratio of 113.7 tons per keg of powder
to 35.6 tons. As to the output of the machine, it may be
said to be an average annual of 12,000 tons, with two men as
runners, ten as followers, engaged in the various occupations
of timber-men, track-men, loaders, etc. The Harrison per-
cussion-machine is expected to make eight entry cuts per day.
In a coal-seam seven feet thick, worked by the pillar-and-room
method, the monthly output was 78.93 tons per man, count-
ing all men who perform the ordinary functions of the miner;
an all-hand-labor mine in an 8-foot free coal-seam produced
69.55 tons per man per month. In a 4.5-foot seam, free from
impurities, the reciprocating machine averaged 28 tons of
lump coal daily, which equals 42.5 tons of run of mine. This
represents in this vein an average undercut of about 170
square feet. A plant running 12 machines, and in all the
standard makes, will cost about $12,000. In operation one
machinist will tend to and keep in repair 30 machines, and
one blacksmith can sharpen the tools, etc., required for about
400 tons daily output. In Illinois the cost of maintenance of
one machine is not far from $20.00 per year.
In Hocking County, Ohio, during 1894 but one fatal acci-
dent occurred in producing 1,453,391 tons, 73 per cent of
which was mined by machinery. Whenever coal is mined by
machine and the records are available, the facts demonstrate
a marked decrease in the accident list, and this is due to the
fact that no men are exposed to the danger from fall of coal,
and but very few to that from the caving of sides or unsup-
ported roof. Again, the men selected to operate the machine
and to prepare the coal usually are of the higher order of
488 MANUAL OF MINING.
intelligence found among the craft, and the other duties of
the miner are assigned separately to the men, thus giving to
each a specialty in which a greater or less experience is
acquired. Accidents from powder-explosions, too, are very
rare. The fact that 12.8 men on an average attend each
machine, is a sufficient answer to the complaint of their
replacement by machines; for, while less men may be actually
employed in cutting the coal, a larger number of extra men
would be employed attending to the machine, laying rails,
putting up timber, blasting, loading, etc., and for the increased
output obtained from the machines, as compared with manual
labor. The one class of common laborers required is that of
loading coal on the cars, each machine requiring four to eight.
Again, as to the effect of the machine upon the miner's
wages, experience proves that the introduction of machines
has always led to an increase and not a decrease in the amount
earned by the miner; and this, coupled with the easier con-
ditions under which his labor is applied, must appeal to him
strongly. The disadvantages rated against the machines,
are: (i) waste of coal, (2) larger cost of plant, (3) necessity of
a thick seam, (4) necessity of careful and skilful supervision.
The introduction of machines decreases the number of
strikes, decreases the number of delays of standing shots,
requires more systematic development of the mine, giving a
steadier output, and concentrates the operations because less
territory has to be kept open for the machines whose output
exceeds that of hand labor, than in mines worked by hand
only.
To keep seven uninterruptedly at work, there are neces-
sary from three to five additional ones.
The following references are cited:
Ohio Mine Inspector : Coal-miiiing Machines, R. M. Hazeltine, 1895,
22.
Coll. Eng.: Relative Advantages of Machine Cutters, Anon., Feb.
1897, 313-
Atner. Mfr.: Discussion of Present Form of Machine Cutters, Cyrus
Robinson, Jan. 1897, 121; Efiiciencv of Modern Mining Machinery,
Cyrus Robinson, April 1897, 588.
DRILLS AND DRILLING. 4^9
Coll. Guard.: Machine Mining and the Labor Question, W. E. Gat-
foth, 1897,480, Coal-cutting Maciiines in Long-wall, England, T. B. A.
Clarke, Dec. 1896, 1078, Coal-cutting by Machine in Iowa, Foster Bain,
June 1897, 1085 ; Coal-cutting Machines tor Pillar and Stall or Narrow
Work, John Davis, May 14, 1897, 918, Coal-getting Machinery. Chas.
Latham, 1897, 133.
Eng. Mag.: Diamond-driU Prospecting, ]. Parke Channing, Mar.
1896.
Ontario Bureau of Mines : Exploring by Diamond Drill, Cost, etc.,
Archibald Blue, 1895, 221, 4th Report, 1893, 164.
Mine Inspector : Electricity in Bituminous Coal-mining, Robt. M.
Haseltine, Ohio, 1894, 18.
Fed. hist. M. E.: Notes on Coal-gettmg by Machinery. T. H. Words-
worth, VL and VIL; Blakemore, XI. 179.
School of Mines Quarterly . Diamond-drill Prospecting, Rich. A.
Parker, XVL 31.
E. &^ M. four.: Curvature of Diamond Drill-holes, J. Parke Chan-
ning, LVIIl. 268; Coal-cutting Plant, General Electric Co., T. W.
Sprague, LX. 57.
Anier. Mfr.: Machine-mining in Ohio, 1897, 193.
Coll. Man.: Application of Machinery to Coal-mining, J. Hunter,
1894, 4, Tunnels in Coal Mines, Cost of Driving with and witliout Ex-
plosives, M. Elce, Dec. 1S93, 222.
Ainer. Inst. M . E.: .\ Simple Apparatus for Determining the Rel.i-
tive Strength of Explosives, S. Whinery, XIV. 75; Cost and Results of
Geological Explorations with the Diamond Drill in the Anthracite
Regions of Pennsylvania, Lewis A. Riley, V. 303; On Rock-drilling
Macliinery, E. Gybbon Spilsbury, III. 144; The Diamond Drill for Deep
Boring compared with Other Systems of Boring, Oswald J. Heinrich,
M.E., II. 241.
Trans, of the A', of Eng. Inst, of M. ill. Eng.: Coal-cutting by
Machinery, W. Blakemore. XLV 177.
Engineering Association 0/ the South : Coal-cutting Machinery, Jno.
B. Atkinson, Pub. No. 4.
Mineral Industry : Coal-mining Machines, A. Dick, 11. 230.
F^ng. News: Electrical Coal-cuttmg, J. T. Burchell, Apr. 6, 1893,
334-
CHAPTER IX.
THE COMPRESSION OF AIR.
93. Theory and principles; lieating during compression; influence of
altitude; losses in the compression; equalizers and compound
cylinders ; construction of the machine and its requirements ; means
for rendering the resistance of the piston uniform. 94. Calculation
of the work done upon the air; tables; formulas; discussion of
the valves and forms of the principal air-compressors on the market ;
air-receivers and their form and utility. 95. Conduction of the air;
air as a motor; pipes, expanders, etc. ; theory in the operation of
the motor; tables of losses by friction ; discussion of the economy
of working with or without expansion. References.
93, Any of the machines described in the previous chapter
may be run by air or steam ; but though steam is the cheaper
motor, air has the advantage of giving cool, dry, ventilated
rooms.
When air is subjected to pressure, its volume is proportion-
ately diminished (see page 242), and, transported, its expansion
is capable of being applied as is steam. To secure 100 lbs. of
absolute pressure from "free air," its volume must be reduced
to 0.147 the original bulk ; for 200 lbs., 0.074. To obtain the
same pressure from steam, it must be superheated to 338° F.
and 388° F., respectively. By "free air" is understood air at
the atmospheric pre.ssure of 14.7 lbs. per square inch, absolute.
By absolute pressure is meant the pressure above a vacuum,
distinguished from gauge-pressure, which is measured above
the atmosphere (14.7 lbs. absolute).
Owing to the molecular repulsion in gases, a compression
of volume cannot take place without a corresponding develop-
ment of heat, the increment varying with the initial tempera-
490
THE COMPRESSION OF AIR.
491
ture, as the accompanying table shows. The last column givey
the factor of ratio between the initial and final absolute
temperatures, t and T, of the air. (^ -\- 459)/ = 7" -|- 459.
Giiuge.
Volume
Volume
Temperature,
Temperature,
Factor.
isothermic.
adiabatic.
Deg. Fahr.
Deg. Fahr.
0.0
I .000
1. 000
.6l.
90.
14-7
.500
0.612
175
6
211 .9
1.222
29.4
•333
0.459
255
I
294.2
1.375
44.1
.250
0.374
317
4
362.0
1.495
58.8
.200
0.319
369
4
417.0
1-595
73-5
.167
0.281
414
5
464.8
i.68i
88. 2
• 143
0.251
454
5
506.8
1.758
If this compressed air be immediately used in an engine, it
will return to its initial stage of temperature and pressure.
This expansion is said to take place adiabatically, — freely,
without receiving heat. At 461.2° F. there is no pressure.
The above table is based on a sea-level pressure. At
different altitudes the absolute pressure and density vary as
below.
Altitude.
Pressure.
Density.
Sea-level
14.7
1. 00
\ mile above
14.0
0.96
4 " "
13-3
0.91
3 a a
12.7
0.86
I "
12.0
0.82
li " "
ir.4
0.78
i^ " "
10.9
0.74
2 "
9.9
o.6^
The increase in temperature is an obstacle to rapid run-
ning ; it tends to expand the volume so heated, as indicated
above. If, however, the expansion is resisted, the heat re-
acts on the compressed air and increases its tension and,
consequently, its pres.sure. The increase of resistance to com-
492
MANUAL OF MINING.
pression is 0.00204 of the pressure for each degree Fahrenheit.
A volume of air which has been compressed to 73.5 lbs. has a
temperature of 414.5° F., by reason of which it would expand
to 1.78 times its original bulk, in accordance with the following
formula': 4912/ = u (491 -\- T — t), in which the volumes ti' and
u correspond to the temperatures T and t. Since, also, it is
impossible to contain the heat, spite of every precaution, and
there is no necessity for its retention, it is extracted as soon as
possible. The loss of heat begins with the instant of its
development by radiation from the conducting-surface of the
cylinder, receivers, and pipes. The cooling attachments added
to the cylinder more or less perfectly complete the dissipation
of heat and permit an isothermic compression. It may be
noted that the increment of heat is greater in the early stages
of compression than toward the final ; so the cooling is best
done at the beginning of the stroke.
Fig. 257 is a graphic representation of the adiabatic and
isothermal curves of air. The volumes of air at various times
Fig. 257.
are laid off on the horizontal line and their corresponding pres-
sures may be measured by the verticals. It will be seen that
the adiabatic curve rises more rapidly than the isothermal or
than the intermediate condition of cooling attained in the com-
494 MANUAL OF MINING
pressor. The indicator card also shows the behavior of steam
when expanding from 58 lbs. pressure at 0.3 cut-off.
If the air cools, while its volume remains constant, a fall in
pressure ensues, and the capacity for work in re-expansion is
reduced. This is a serious loss, and is greater with the degree
of compression. Rankine showed that the loss is rarely less
than 65 per cent of the work performed by the motor. For
I, 2, 3, 4, 5, and 6 atmospheres, gauge-reading, the losses are
28, 37, 46, 50, 53, and 56 per cent of the original power. That
is, the higher the pressure, the less is the efficiency of the ex-
panding-engine. It is also greater if the cooling be not effected
in the cylinder. Although the heat has been extracted from
the air, it is still under pressure, and its unrestricted (adia-
batic) expansion is yet capable of producing work ; but by no
means to the extent otherwise possible. There remains only
the potential energy of the comparatively cool air, which is
discharged at a temperature of about 180 F., amounting to
somewhat over 6000 ft. lbs. per cu. ft.
Economic work is best obtained, then, by operating at as
low pressure as consistent with the work. Again, if the air
could be cooled before compression, so that after compression
it will have the temperature of the surrounding air, better work
would be done. The storage, too, of high-pressure air is diffi-
cult. The loss would be less if the air was heated, during its
use, to an isothermic condition. This is impracticable, ordi-
narily.
Thus it becomes essential that the engine have its greatest
power during the early part of its stroke, and yet drive the air-
piston, with its maximum resistance at the end. For high
pressures the difference is very marked. Single-acting conical
cylinders have been used, but the compound-air cylinder has
proven more effective for this purpose. In Fig. 258, the
air, after a partial compression in D, is forced into the small
cyhnder G, where the operation is finished. The arrows show
the directions followed by the air. This renders the resistance
more uniform than where the compression is effected in one
cylinder. A fly-wheel, and heavy parts, are partial equalizers,
THE COMPRESSION OF AJR^
495
496
MANUAL OF MINING.
adding to the power when the steam is weak by expansion.
Tlie ratio between the air-resistance and the steam-pressure is
fixed by the relation between the areas of the steam- and air-
cylinders.
The air-cylinder is connected, directly or through inter-
mediate gear, with the steam-cylinder, or geared to a water-
wheel. It is simple or compound, and single or duplex. The
air-cylinder is said to be " tandem" to the steam-cylinder when
their pistons are extensions on the same rod ; and " crossed,"
when alongside and joined to a cross-head. Its operation is
identical with that of the steam-pump, and, substituting air for
Fig. 261
water, and dispensing with the air-chamber above, Fig. 93 may
well represent the air-compressor.
94. The absorption of the heat of compression is accom-
plished by a cold-water jacket surrounding the cylinder. For-
merly, a spray of water, injected into it, extracted the heat ; but
owing to the obstruction of the machmes by the formation of
THE COMPRESSION OF AIR.
497
!■ i^^^,
■'5r"'\'i^ir '
THE COMPRESSION OE AIR. 499
snow, in use, the plan was soon abandoned. The accom-
panying figure (260) is a section of the Rand cylinder, show-
ing the coohng-jacket space, outside of which is the air-inlet.
Fig. 261 illustrates the direct-acting duplex compressor, one
liaif of the plan, being in section. Fig. 262 is a view of the
Norwalk pattern, of which Fig. 258 is a section.
The cooling-water should be taken very cold, and the cyl-
inder-lining should be a perfect conductor of heat in order to
extract an appreciable amount of heat for the time of contact
between the water and heated air is very short. In com-
pound cylinders the air meets two currents; but even they
cannot perfectly cool the air. So, often, an additional cooler
is used, E, Fig. 259, in the Ingersoll, and F, Fig. 258, in the
Norwalk. A reservoir filled with thin brass pipes circulating
culd water offers a very efficient cooling-attachment, which
saves as much as 10 per cent of the power, and about counter-
balances the friction of the machine. Perfect cooling of 60
lbs. air would save at least 20 per cent of power.
The work of isothermic compression during one stroke of
the piston is measured by the formula
H/= />(;-+ V) hyp. logl^^Jr^, - {P' - P)v ■
in which f^and T" are the volumes of gas at /'and P' lbs.
tension per square foot, and v is the volume of the clearance.
The work of adiabatical compression per pound of air is
183.43(7" — t), T, t being the initial and final temperatures,
measured in degrees Faiirenheit. It requires about 0.19 per
cent more of work for every additional 1° F. of warmer air.
One pound of free air at 90^ F. raised to 88. 2 lbs. pressure
and to 464.8° F., requires 68,757 ft. -lbs. of woik; of air at 60°
F. to the same pressure, requires 67,171 ft. -lbs. For this
reason, and that its density is greater, the air should be
taken frnni outside of the engine-room.
Moreover, tlic air should be dry and free from dust, to pre-
vent clogging of the machines, though the work of compress-
ing a pound of dry air is somewhat more than that for moist
500
MANUAL OF MINING.
air, as the accompanying table shows ; so, too, the tempera-
ture of the dry air rises more rapidly than that of the moist.
Temperature.
Work on One Pound.
Pressure.
Dry.
Moist.
Dry.
Moist.
14-7
68° F.
68° F.
22.
133-8
94
13,300
13,200
29.4
185.9
III
23,500
22,500
36.7
229.5
124
30,500
29.000
44.1
266.7
135
37,000
35,000
51-4
300.2
145
43,200
40,600
58.8
330.1
153
48,500
45,000
73-5
383-5
167
58,500
52,500
88.2
428.9
179
67,160
60,000
One inevitable source of reduction of cylinder-capacity is
the clearance-space between the piston and the cylinder-head
at the end of a stroke. The warm air filling it is never dis-
charged, but, on the return stroke, expands and fills a volume
that should have been occupied by the fresh atmospheric air.
An increased length of stroke, or compounding the cylinders,,
are the only remedies. At 75 lbs. pressure, the single cylinder
must be over three times as long as would the compound for
equal clearance loss. Manufacturers dare not plan for a smaller
than yV' clearance. A German device for obviating the effect
of clearance consists in effecting a communication between it
and the other parts of the cylinder. Indicator-cards show an
increased efficiency of 5 per cent by the use of the contrivance
in connection with a dry slide-valve.
The valves of the compressor are of the poppet, spindle, or
ring patterns. Whatever their form, they should open quickly,
have a full lift, and be ample in size. The inlet valves offer
little difficulty, though for a short time they are subject to full
reservoir pressure. An unrestricted entry for the air is obtained
easily by the use of poppets held by springs. The Ingersoll-
Sergeant compressor admits air through a hollow piston and
rod (Fig. 232), and thus leaves more room for the discharge
valves and the cooling-surface. The Norwalk-employs a Cor-
liss valve. The inlet valves of the Rand are shown at si, s^
THE COMPRESSION OF AIR. 50 1
Fig. 260. They are provided with guards that prevent fall-
ing into the cyHnder.
The valves should be positive, and this the poppet obtains,
though the tendency to "chattering" is the serious objection to
it, particularly for discharge-valves, This arises from the two
opposing efforts — one, of the air, to open, and the other, the
spring, to close the valve. The Norwalk-Corliss pattern does
away with this trouble in the high-pressure engines ; as also
does the valve-gear shown in Fig. 233. The arms, a, b, relax
the spring-pressure and allow of the valve rising full lift without
•dancing. Poppet-valves can hardly be improved upon for low
pressures, though their springs lose elasticity and open too
soon. This reduces their efficiency, as also does any slip of
the valves. In the Norwalk pattern (Fig. 235), a positive dis-
charge is obtained by moving the valve by cams, such that it
remains at rest till the pressure is sufificient to open it quickly.
A difficulty about this, it would seem, is that, as the reservoir
pressure constantly varies (unless perfectly regulated), the
the construction of valves should receive careful attention.
This has been corrected by an automatic movement given to
their compressor-valves, which open at different points in the
stroke, as desired.
The discharge valves require careful construction, for their
leakage is equal to a large clearance-space. In order to reduce
the friction of the air passing they are made large, and, to pre-
vent inordinate loss and wear, as numerous as possible. An
excess of engine-pressure over receiver-pressure is necessary to
open the valves and expel the air. This unavoidable loss has
an important bearing upon the uniformity of speed. An auto-
matic regulator assists this to a certain extent, though, as a
matter of fact, a hand regulator is found to be equally satis-
factory for a long line of pipe. There have been devised plans
for unloading the engine, and maintaining a uniform pressure,
even under a heavy draft upon the receiver, but of their per-
formance we have yet no returns.
Thus the simple principle of the air-compressor becomes
exceedingly difficult of execution in an efficient manner. To
obtain a compact, high-speed, uniform, rapidly cooling, eflPicient
engine is not easy. These essentials are secured in various
502 MANUAL OF MINING.
ways in the Burleigh, Clayton, Delamater, Ingcrsoll, Norvvalk,
and Rand patterns. The engines are " straight-line," direct-
acting, or duplex, supplied with fly-wheels, and run by plain
slide-valve or Corliss engine, water- or electric motor. The
direct-acting and horizontal form is preferable, for many rea-
sons, though one objection to the straight-line form is its lia-
bility to centering. Fly-wheels — and some are weighted at
certain points — remedy this somewhat.
High piston-speed is advantageous for economy of steam
and capacity ; but rapid wear, the difificulties of large valve-
area, and the inordinate resistance developed, forbid a greater
velocity than 300 or 400 feet per minute, except in the larger
sizes. Automatic valve-gear, on the Rider system, are also
added now ; they entail no loss of steam, and, with the variable
cut-off, regulate the engine speed. High-test cylinder-oil is
required for lubrication ; graphite is the best lubricator.
Duplex engine connections are by cranks at quarters. The
frames are solid and well founded. For purposes of trans-
portation to remote camps, they may also be had sectional.
Water-power and wheels are admirably adapted for this work.
Two 66" Swain turbines, with 16' fall, run four compressors
24x60, furnishing air for 20 drills, 8 hoisters, and 17 pumps,
at the Republic mine. At the Anaconda, the 30x60 duplex,
with Corliss valves, is the largest compressor that the author
knows of.
The Burleigh is upright, and its peculiarity lies in the
comparative sizes of the cylinders, and in admitting steam one-
eighth of a stroke before the air. Its air-cylinder is single-
acting. The Clayton has the usual poppet-valve, and is a
compact machine, with its fly-wheel centrally located. The
Delamater has an important contrivance for dropping the dis-
charge valve from its seat. This form is very heavy. The
IngersoU, Norwalk, and Rand are the popular pneumatic ma-
chines. The Waring has a bonnet, or conical valve, like that
in Fig. 233. Its pistons are moved by a rocker on the fly-
wheel, the steam-cylinder being set at an angle to the horizontal
air-cylinder.
THE COMPRESSION OF AIR.
50,^
The discharged air is stored in a receiver, whence it is with-
drawn as required. It is simply a strong iron reservoir, of any
convenient shape, and commodious enough to meet any
draught upon it.
95. The air is conveyed to drill, coal-cutter, hoister, etc.,
by pipe, and in its transmission a great loss is experienced
by reason of the friction.
Recurring to the formula in I, 50, it will be recalled that the
frictional resistance is directly proportional to the square of the
velocity of the flow, directly as the length of the conduit, directly
as its periphery, and inversely as its area, or the square of its
diameter. As the periphery is proportional to the diameter
the resistance becomes an inverse function of the diameter.
Tables are given by manufacturers of the loss of pressure by
flow in pipes, and it will be found therein that air at 32.8 feet
per second loses 8.26 lbs. pressure in a mile of lo-inch pipe,
10.04 hi an 8-inch, and 20.08 lbs. in a 4-inch pipe. Below is ap-
pended a table giving the loss in pressure,/, for various veloci-
ties, V, in feet per second, and different diameters of pipe,
length being looo feet ; q is the volume of " free air" passing
per minute (air-cylinder capacity), corresponding to an assumed
gauge-compression of 60 lbs.; ^', the volume at 80 lbs. This is
copied from the Norwalk Iron Co.'s book.
i"
3"
4"
6"
10"
V
/
V
9'
P
1
1'
P
1}
1'
/
ressures
and any initial absolute temperature, /. Solving, as above,
7'=^ 930" absolute ^ 469° F and the work of adiabatic compression;
IVi = 183.45 (930° — 529°) 80 = 5,886,680 ft. -lbs.
The following references are cited:
Coll. Eng.: Compressed-air Haulage, Glen Lyon, Pa., Editorial, May
1S96, 226.
Mill. &>• SciciiWfic Press: Uses of Compressed Air for Mining Pur-
poses, E. A. Rix, June 1897, 501.
Franklin Inst. Jotir.: Electricity <',(. Compressed Air, Herman Haupt,
Jan. 1897, II : Compressed-air Haulage, Herman Haupt, Feb. 1897, 119.
Coll. Guard.: Air-conipressors, Test cjf a Two-stage, John Goodman,
July 1897, 165; Use of Compressed Air in Mines, M. Mortier, Jan. 22,
1897, 159, Compressed Air at High Pressure for Tramways, " M. E."
July 13, 1893, 6i , Compressed Air Plant at a Colliery m Saxony, reprint.
May 3, 1895, 844.
THE COMPRESSION OF A IK. 5O9
Engineering Mag.: Uses of Compressed Air, Historical Data, Curtis
"W. Shields, Dec. 1896, 516 ; Jan. 1897, 657.
Eltc. ling.: Electricity vs. Compressed Air in Colorado, L. Searing,
Nov. iSg6, 528; Will Compressed Air Rival Electricity for Tramways,
Wm. Baxter, Jr., Sept. 30, 1897, 32S.
5. of i\[. Qiui?t.: Air-compressors, R. Peele, XVIII. 196.
Cal. Mitieralogist : Compressed-air Plants, Water Power, 13th, 706.
E. J-» HI. Jour.: Uses of Compressed Air, Chas. A. Bennett, LIX.
100; Ecorioniy in Air-compression, Frank Richards, LIX. 269, Chas. A.
Bennett. LIX. 290; Air-compressor Plant, Nottingham Colliery, LVII.
125; Coal Consumption for Air-compressor, L. de Munmont, LVI. 618.
CHAPTER X.
MINE EXAMINATION.
96. Examination and evaluation of mines ; sampling and measuring
tiie deposit; features to be noted; capitalization; "ore in sit;ht."
97. General remarks regarding the treatment of ores; factors
determining their value; deleterious substances; various milling
processes; cost of mining; formulae for mine valuation. 98. The
mining-labor problem; variety of skilled labor employed; selection
of men; necessity for regulations and their enforcement; conven-
iences, liygienic and otherwise; number of shifts and their length ,
mode of paying; necessity for reciprocity; day's pay vs. tribute
system; contracts and the mode of letting; pay by the output or
progress; dead work; leasing mines. 99. Retrospective. References
96. The e.xamination of a property with a view to pur-
chase or exploitation will not be a difficult nnatter to one who
is cognizant of all the local economic conditions, and is familiar
with the geognesy of ore-deposits. It calls for the exercise
of sound judgment and technical instinct which we endeavor
to cultivate : these faculties are self-taught ; observation and
caution will strengthen them. Vigilance and prudence pre-
vent many of the fatal mistakes to which hasty conclusions of
the human mind are prone. You cannot foresee or predict in
detail the future of a mine. Your only basis is the general
canons. To apply these to the selection of a system and plant
you must collect and investigate all data in any degree
suggestive.
Proceed to a careful study of the survey maps of the
district, for they will assist in your determination of the trend,
frequency, extent, and size of the ore-shoots. Close investi-
gation of any idle mill or abandoned works in the vicinity, and
the commonly received opinions regarding the causes of their
510
MINE EXAMINATION Srr
i'ailure, may prove valuable as a guide. Converse with the
miners, as they are in possession of valuable details, and may
be able to furnish the history of similar enterprises. Consult
all convenient sources before visiting the mine, then "sort"
out the prejudices, "screen" the ignorance, "jig" the balance
by technical knowledge, and examine the "concentrates" for
probabilities.
On visiting the property proceed systematically with the
geological examination of the enclosing rocks, the character of
the vein matter, and its irregularities of thickness or pitch.
Look closely for faults or slides. Collate the data thus
obtained, and determine if the deposit be gash or fissure,
pocket or bed. Note the toughness and hardness of the vein
matter, the security of its walls, and the width and softness of
the ore-streak with a view to calculating the cost of mining.
The dimensions of horses, partings, or barren ground and the
cost of their removal should be considered; as also the quality
and quantit)' of the other available materials for support.
Wherever the mineral is exposed, samples are to be taken
for assay to ascertain its value and quality. Every variation
in the dimensions or character of the ore body should be
sampled in a line across the entire exposure. Each streak or
bench may differ and require sampling. In every case describe
in the note-book the appearance of the face, its location, and
the width of the streak. Take the precaution to arbitrarily
select the spots for tests, and collect a sufficient quantity of
each constituent mineral of the ore for its separate assay.
Obtain freshly blasted or picked material. Examine closely
for any evidences of concealment by plastering or timbering
up of poor faces. Take " grabs" from the cars or stock piles.
It would not be amiss to sample the dump. A sheet of paper,
cut into snips, is thrown to the winds. Grabs are taken where
they alight on the dump. The size of the dump will convey
some idea of the amount of the work done. Seal all bags
immediately upon filling, and leave no opportunity for injec-
tion in them of strong solutions of mineral, or other "salting. "
Take all measurements that will serve as guides in estimating
5i2 MANUAL OF MINING.
the area and extent of the vein or bed, the amount or value of
mineral capable of extraction, and the amount and value of
that to be left for filling, mined or unmined. Be cautious, and
secure results as accurate as can be measured. In estimating
the "ore in sight," it is fallacious to be too liberal. Include
only the mineral in the blocks exposed on at least two if not
three faces by the connected drifts, shafts, or stopes. Be care-
ful, then, in the use of this term. It is often reactive. In
computing the body of mineral remember that all is not sold.
A portion is not mined out, some is buried in the waste, some
discarded in sorting, and some lost in the concentration. The
ratio of the volume sold, as per smelter and mill returns, and
that of the work done, will prove a reliable guide. Likewise
with coal : of its actual volume every acre will sell about looo
tons for each foot of thickness of the bed. Mines only slightly
developed are not readily estimated ; but by comparison with
the records of neighboring properties a rough estimate may be
made, bearing in mind that in veins, a proximity to profitable
mines is of less monetary value than in beds. From the
calculation of the volumes of mineral and their several assay
values, the property may be evaluated. While enormous
reserves and untold wealth may thus have been found, a great
deal of hard systematic work must be done before the mineral
has been mined, shipped, and drawn against. Several mines
may be quoted carrying large bodies of i^ ounces of gold,
which are absolutely worthless because the ore is rusty. So
with a 55 per cent sulphurous iron ore, a 46-inch coal vein with
5 partings, or a 20-foot zinc bed with pyrites. For this reason
the term " ore in sight" should only represent its net value.
The quantity of coal in an acre of bed is found by the con-
tinued product of 100, the number of inches thickness, and the
specific gravity of the coal. For bituminous coal it is 1964
tons, and for anthracite 1775 tons per foot of vein-thickness
per acre of area.
The cash value of a mine is that which will net a given
annuity to the investors. The amount of this dividend should
increase with the risks run. At best mining is somewhat pre-
MINE EXAMINATION. 513
carious because of the variability of its dependent elements,
and a greater return is expected from it than from U. S.
bonds. So the annuity should be 10 to 30 per cent in addi-
tion to the legal rate of interest. Moreover, the deposit not
being inexhaustible, the life of the mine becomes a matter of
mathematical calculation, which must needs enter our esti-
mate. Against this depletion, and the wear and tear of the
machinery, the sinking-fund must provide. The yearly con-
tributions to it must create a new capital within the period of
its life, which unfortunately is often limited by the impatience
of the operators to extract the ore in the shortest possible
time. The mine is not a permanent source of revenue, and
for the period representing its life should return an adequate
income.
On this account a partly opened mine is depreciated by the
amount it has shipped, but, on the other hand, this develop-
ment work has more or less demonstrated its value. Prospects
are mere speculations, and their values are inversely as their
chances, which must be carefully weighed. The probable con-
tinuity of the ore-shoot to a reasonable extent may be quoted,
but only as a speculative guide. Every mine, till its value has
been assured by a steady output, is a business speculation, and
must be considered as such. It may only be compensated for
by the high prospective rate of interest. True, the security is
not invariably as good as under some other investments, but
safety and income are complements — in fact, reciprocals of
each other. Those demanding security must content them-
selves with a moderate interest. So be explicit and frank in
your estimate, that your client may be assisted in judging of
the risks as well as the returns. Better recommend it for the
cultivation of mushrooms than indulge in any imaginative
representations, or juggle with figures.
Investigate full)' the condition and security of timbering,
filling, pillars, and other supports of an abandoned mine with
a view to the cost of their reinforcement. The cost of reopen-
ing it may exceed the estimated value of the deposit. The
causes for its abandonment are numerous. It may have been
due merely to the inflation of its stock beyond a fair dividing
514 MANUAL OF MINING.
basis, or to a lack of ready means of communication which
time has improved. The exhaustion of means with which to
prosecute work may liave been the cause of shutting down.
Discord among the co-owners is a very common cause of fail-
ure. Be careful in accepting the testimony of their books.
Tlie permanent-improvement account is often delusive, because
it is frequently made to cover awkward expenditures. Take
no cognizance of those entries appearing upon the permanent-
improvement account dated subsequent to the moment of
actual production.
If the results of the examination do not prove sufficiently
positive, or the information regarding the geology or extent of
the deposit be insufificient to satisfy the expectancy of a good
annuity, duty to your clients requires a full, frank statement,
overrating neither the difficulties nor the value of the prospect.
A six-months' working bond and option may be advised, or
the diamond-drill may be resorted to. Before recommending
purchase or exploitation, be sure that the enterprise has a
raison d'etre. Then proceed to a consideration of the capital
required.
A justifiable capitalization is one necessary for the proper
equipment of the property commensurate with the prospective
annuity. This depends upon the scale upon which the property
is to be operated. The amount of exposure and the number
of faces for attack fix the number of men that may be employed,
and either they or the hoisting capacity, the output. For rea-
sons of economy it is advisable to open large areas for attack.
This regulates the quality and quantity of the product, and
reduces the per-ton working expenses; but maintaining much
open ground is expensive, and large capital is needed for the
extensive equipment. The choice between this plan and con-
servative work depends upon the commercial results antici-
pated. Having figured the amount of capital requisite to
properly complete the plans laid out, do not accept any com-
promise with the parsimonious efforts of the directors, and
attempt to work on less than what is deemed necessary for a
successful issue. It is simply inviting failure and disappoint-
ment. One canon must be distinctly laid down — that some
MINE EXAMINATION.
5'5
time must elapse before returns can be realized. Be not over-
sanguine in prophecy.
97. All the material coming from the vein must be either
valuable, worthless, or injurious, and a metallurgist's skill is
requisite in figuring upon the disposal of the ore constituents.
The ore is either milling, concentrating, or smelting. A simple
ore may be hand-dressed to advantage, though often the gangue
is acceptable as a flux, and is not removed w^ith the deleterious
matter. The average smelting ores are silicious, and a basic
gangue is acceptable if it is not a sulphide. A bonus is paid
for an ore with a basic excess. Pyrites injure the quality of
coal, iron ore, galena, and gold ores. Coarse auriferous pyrites
may be cheaply stall-roasted to advantage. Otherwise wash-
ing is the only means of elimination. Blende is objectionable
in smelting, and if argentiferous, in roasting. It interferes
with amalgamation in pans. Jigging will separate it, and that,
too, clean enough to be salable. The roasting of blende and
pyrites at the mine for the manufacture of sulphuric acid is
suggested as a means of rendering all the constituents market-
able without great additional expense. Do not forget, how-
ever, that some of the valuable mineral is lost in the operation,
and in order that the proper system be adopted to minimize
the loss, the assay value of each constituent mineral should be
ascertained. Very frequently the blende of an argentiferous
ore has all the silver. Concentration under these circum-
stances would be useless.
Gold and dry ores m^y be treated by lixiviation, or smelted,
and a few with little zinc and lead are better treated by pan
amalgamation. These ores are rarely concentrated. Iron
oxides with from 25 to 60 per cent of metal are treated as ores.
Those with titanium, phosphorus, or sulphur are rejected.
If intermixed with clay or loam, they are washed and picked
at slight expense. Coal is everywhere acceptable, and is mined
with profit if the bed is over 30 inches thiclc. Whether for
gas, coke, or fuel, purity and calorific intensity are prereqm'sites.
Coals are classified by the fuel ratios of their fixed carbon to
5l6 MANUAL OF MINING. .
volatile and combustible matter. Clay is frequently washed
and dried.
Hence it follows that every new mining company has this
problem to solve, — how and where to treat the ore. A smelter
may be built, when the ore is unfailing in quantity, but a va-
riety must be at hand. On a big scale, and in close proximity
to fuel, it is a most successful method. A concentration-works
may be built. Such a mechanical treatment is applicable to
almost every variety of ore. An amalgamation or a leaching
mill may be erected, but fuel must be cheap and smelting
charges and transportation high before competition with smelt-
ers will pay. The unchangeable character of the ore is essen-
tial to the success of any mill. Before laying the foundation
the mine must be fully opened to at least a two-years' reserve,
as otherwise another sad mistake may be added to the long
list of monuments to similar folly that grace our gulches.
Nothing is so certain as the uncertainties of vein continuance.
Instances are not rare of sudden changes — a lixiviating ore to
a heavy lead-zinc mineral ; galena to bornite ; free-milling to
smelting ores ; etc., etc. Proceed cautiously in this matter,
minimize the risks, and limit the capitalization. Many a com-
pany has been brought to an untimely end by the bane of min-
ing — ill-advised surface improvements. Extensive plank-roads
may be dispensed with till there is something to ship.
Several investigators have prepared algebraic formula
which, after the substitution of the values for the variable fac-
tors in a particular instance, will give the price to be paid, or
the capital required. Amadee Bruat, Miller, R. W. Raymond
and Prof. P. H. van Diest have contributed to this line of
mathematical research. While in the hands of a proper man-
ipulator these equations may be satisfactory, it is not safe to
entrust the novice with the solution of so intricate a problem
as the evaluation of mines by an inflexible rule, into which
cannot enter fully all the varied local conditions.
It is unfortunate that in this recital of facts the cost of
mining cannot be quoted. The reasons are easily understood.
In the Lake Superior region it varies from 94 cents to $3.40
MINE EXAMINATION. 5 '7
per ton of copper rock hoisted. Gold is mined and milled for
from $2 up. All the expenses of iron-ore extraction are not
over $2.iO per ton in some localities. The cost of coal-mining
varies from 62 to 90 cents per ton. In one section of Colorado
a $25 lead ore pays handsomely, while a similar $40 ore near
by is unprofitable. No constant proportion exists between the
labor and the other items. The ratio of dead-work to ground
opened varies considerably with the anxiety of the operators
and the proportion of gangue. Ordinarily, the cost of stoping
per cubic foot will be one tenth that of drifting, a thirtieth of
the sinking, and a fifteenth of the upraises.
98. Besides a familiarity with the practice in vogue among
his neighbors, the engineer must have an intimate knowledge
of human nature, that the mine-labor problem may be success-
fully cqped with. The large number and variety of men em-
ployed, the selection of men and their treatment, are intricate
■questions, delicate of adjustment.
Besides the foreman, boss, or " viewer," who is the chief
officer, parallel with the superintendent of the metal-mines,
we have captains, " butties" or contractors, timbermen, shaft-
men, masons, hewers or miners, trappers to look after the
doors, trammers or " putters," drivers, engineers, etc. The
adjustment of their pay and hours is a difficult matter, and is
the primary cause of strikes and lockouts. The design should
be to secure a mutual interest of miner and employer, in the
g-ettins of the maximum of ore in the minimum of time.
Good miners are essential to the success of the property, and
an ability to judge of their competency is a trait which only
long experience can form. A good miner can strike right or
left handed, knows the mode of carrying on the work without
further notice, and a single-handed man is worth the best
wages going. An inexperienced miner is of no earthly ac-
count. He will drift off from the vein into the country be-
cause it happens to be softer, or from ignorance he will shoot
mineral and gangue together and necessitate extra sorting ; his
consumption of steel and powder will be excessive, or his
shots will " pop ;" he cannot hold well for the striker, or he
5 1 8 AfJ NUAL OF MINING.
will bruise his mate ; and he is likely to leave a bald face for
the next shift to break from. In all, the greeny costs more
than he brings.
The men being scattered in little gangs throughout the
mine, the whole force cannot be under the superintendent's
eye, and the grossest dereliction of duty may escape his notice.
For these and other reasons a uniform pcr-diem wages is
an unsatisfactory solution to the problem of pay. The old
hand certainly should command more than the tenderfoot.
The quality and quantity of his work deserves better remuner-
ation, and yet troLible is engendered by attempting to grade
the clay's pay of laborers on the same class of work. No one
but a saint would undertake this.
Some form of contract system remains as a solution to this
problem. Dead-work can readily be arranged for at a meas-
ured rate of pa)'. Contracts by the foot or fathom can easily
be regulated to mutual benefit ; and the plan of fixing a certain
minimum and maximum of earning has universal favor in the
Lake Superior region. The mode of letting contracts by
" shift option" is common. Shift or gang No. i has the first
bid, No. 2 the next, etc. ; after all have given their bid, a chance
is offered to any one to underbid the lowest. Besides dead-
work, the mining of rooms or stopes in ore of uniform grade
and quality is also contracted out in this manner on short
times. During the winter, when shipments arc slow or impos-
sible, the contracts for dead-work are best let.
In the case of contracts there is an incentive to labor, but
the interests of the two parties are not identical. The em-
ployii has no more interest in the ore than has the day's-pa\'
miner, and is liable to waste mineral. His sole object is to
show as large a measurement as he can.
In coal, iron, or other bedded mines the pay is by the
car or ton extracted, and the tramming may or may not be
paid for separately. A certain face is let out to a butty and
his men, who may work it in one or two shifts. This plan
requires constant supervision to prevent the admixture of
slate. A certain reasonable percentage of slate or clay is
MINE EXAMINATION. 519
allowable, but an excess over that forfeits the entire car.
What with this trouble and the disputes over weights, the life
of the " tipple boss" is not a happy one. The practice of offer-
ing a bonus to men who exceed a certain given output meets
with happy results.
One difficulty with this class of contracts is that the tim-
bering and track-laying are very apt to be inefficiently done.
This is effectually obviated by active supervision, a subdivision
of the different departments of labor, and their assignment to
specialists. While no system can be devised to perfectly meet
all cases arising from and under it, contracting, in one form or
other, offers a stimulus to intelligent work and fosters habits
of observation. This is particularly true in vein-mining, where
feeders would otherwise be ignored, while their pursuit might
lead to valuable finds.
In the "Missouri flat zinc-beds is maintained a system of
dividing the ground into plots of 200 feet square and leasing
them to operators, who for a definite period of time extract
the mineral therefrom and dispose of the ore to the highest
bidder, through the owners, who retain a certain royalty and
have supervision over the workings. If the work has been done
properly, this plan conduces to the benefit of all concerned.
Without this, adverse results may be expected. It is a profit-
able system where a large territory is to be operated, or where
capital is scarce and immediate profits dubious. Theoreti-
cally, leasing is wrong if applied to mines owned by parties
with sufficient capital for developing ; for if its operation
will pay tlie lessees, it ought to give similar return with com-
pany work. That it frequently does not, demonstrates that
there is " a nigger in the wood-pile." It is true the lessees
will gut the mine of all the ore and will do no exploratory
vork ; but undeveloped mines, or tracts entirely in virgin
''round, have only probabilities on which to base the terms of
the lease, v/hich should be liberal as to t'lne and area. In
developed mines these probabilities can be approximately
computed.
This plan is not confined to the region mentioned. The
520 MANUAL OF MINING.
duration of the lease may be a few months or years. In Eng-
land it continues with the life of three named persons, and
terminates with the decease of the third. The period in any
event should be commensurate with the amount of preparatory
work to be done. A short term would seem to be unjust to
the lessees, particularly if a rich strike is made ; but this is
fully equalized by the custom that justifies the abandonment of
an unprofitable plot, without any forfeit. On the other hand,
the articles of agreement often allow the company to order a
stoppage of work whenever it may desire so to do. Such leases
are recognized by their nature as speculative, and are given
under terms that might be a hardship were it not that the cor-
poration is constrained to act with great honesty.
The great difficulty with this system, like to the others, is
in the adjustment of dues, company and miner rarely agreeing
in estimate. Such differences are inevitable with any form,
and a rigid policy must be enforced.
A similar form of leasing, known as " tributing," is adopted
in its most characteristic form in many of our American mines,
with beneficial results. After the preparatory works are run
and the mine has been blocked out, the stopes are leased for
a month or so on a stipulated royalty. Each gang is expected
to mine with reasonable diligence, to stope up only, to maintain
good timbering, and to deliver the ore at the level mouth.
The company hoists and markets the product and keeps the
mine dry, retaining a certain percentage of the gross values for
the privileges. Other conditions, of timbering, smithing, and
supplies, are imposed, according to locality. This plan works
admirably, except for the trouble over settlements, and is ac-
quiring universal favor.
The men are required to work over-hand, because then the
timbering is within easy inspection. Under-hand is not per-
mitted at all.
In beds and pockety mines, with ores variable in quantity
and quality, this method is profitably pursued, if the manager
is vigilant. Towards the end of the term of the lease, miners
not infrequently plaster up the face to deceive him and obtain
MINE EXAMINATION. 52 t
a renewal on a smaller royalty. Again, much trouble is ex-
perienced in the miners on a poor stope or " pitch" helping
themselves from a neighboring richer tract.
Mines working on a high-grade mineral usually fit up a
room for the change of clothes. The amount of pilfering is
thus reduced.
The length of shift varies from 8 to 12 hours. The latter
is too long, and even a lo-hour shift accomplishes less than an
8-hour. This is so well recognized, that urgent work is divided
up into three 8-hour shifts per day. Men engaged in sinking
or in wet ground have either better pay or shorter hours.
Large mines, delivering the men below in buckets or cages,
lose too much time for short shifts, and they are run under the
lO-hourrule. Of those supplied with man engines and ladders,
the tally is taken below and some use long, some short shifts.
As to the number of shifts, this very important point is
not easily settled. For a given output, two shifts require an
area opened and a roadway maintained, of only one half that
of a one-shift mine. In metalliferous districts, somehow,
night-shifts are not in favor. Certainly, day's-pay mines re-
quire very active, conscientious oversight to accomplish as
much at night as by day-shift.
99, Attention to these economic details is highly impor-
tant. No mine can succeed without good miners and conscien-
tious labor, yet this does not constitute the sole element of
success. The vital point of the laborer's concern is wages,
the proper adjustment of which requires skill, tact, and judg-
ment. Then ability to judge of the quality and efficiency
of their work is only acquired by experience and observation.
Dereliction or incompetency in this latter respect may undo
all the economy and care in the planning and execution of the
engineering details. Under these circumstances, the largei
the mine and the number of employes the shorter the time
necessary to bankrupt the owners.
The designing and selection of the machinery is not by
any means the most intricate or even the most important of
the multifarious duties of the mining superintendent. Com-
522 MANUAL OF MINING.
bined with the matters requiring technical knowledge are the
endless details, including the supervision of ore sales, the
management of men, and the deciding of disputes. A man-
ager incapable of combating these emergencies simply tempts
ill-fortune and invites disaster.
The very nature of ore occurrences is such that the ele
ment of chance must needs figure in mining as it does in othei
business, but with the employment of an equal judgment and
discretion the result should be equally satisfactory.
The selection and choice of a competent manager is not to
be made hastily. The blunder, so frequently committed, of
sending a clerk or relative from the counting-room to " run
the mine" is responsible for the inevitable failure. Not only
is he ignorant of the principles of mining, but he lacks s}'m-
pathy with his surroundings ; nothing recommends him for the
position, except, perhaps, his consanguinity or his integrity.
The selection of an excellent foreman may counterbalance
some of the error in the management, but there is usually
nothing in common between the foreman and the manager
except the question of salar)/, which in the case of the former
is meagre compared with that of the superior officer, who has
little work or experience. The indifference that ensues soon
becomes manifest in all branches of work, and the manager has
no remedy until the funds become low, when he disappears
from the camp, leaving odium upon himself and his class.
Frequently the same superintendent has launched out into
that bane of mining work — premature surface improvements,
palatial residence, ill-advised mill or process for treatment,
and such monuments of folly as should stand out as warnings
to succeeding corporations ; but the same old mistakes follow
one another closely, and striking examples of contrasting ex
tremes are easily quoted.
Until the value of the lode has been demonstrated, neither
mill nor elaborate improvements should be erected, for up
to that time the prospect is merely a business speculation, and
may or may not prove a successful venture. Grass-root bonan-
zas are rare.
MINE EXAMIXATION.
523
' When the plans are being laid, the educated engineer who
exercises the business sense required for any other manufact-
uring pursuit will adopt the tried and true processes: not
necessarily those of the camp,— for custom is time-honored to
men, and innovations arc looked upon with suspicion, and re-
sisted, not having the seal of local usage,— but the most im-
proved methods of successful camps. To such careful, obseiv-
ing management the many mines of Europe owe their con-
tinued prosperity, after three hundred years of working. Of
shrewd business methods, the Atlantic mine (Fig. 5), with its
heavy dividends, 1890, from an ore yielding but 13.27 lbs. of re-
fined copper per ton of rock stamped, is a notable example.
In 1894, Mr. Albert Williams, Jr., in replying to the
mooted question, " Does mining pay ?" remarks that it is
pretty conclusively establislied in tlie affirmative, with certain
qualifications. It does not, if prosecuted loosely and recrarded
as a mere gamble, and if its purchase or investment is not
characterized by business precaution, or it is not opcratetl bv
one of trained experience. " Many of its operations can be
planned and estimated with nearly the same precision as
bridge-building and railroad work."
By actual and costly experience, the " practical man"
learns what the " theoretical man," the graduate, has been
taught — that to profit by the experience of otlieis is wis-
dom. Sj'stem will replace obsolete, crude hand-to-mouth
methods of yore, and many an idle mine may be quoted that
one keenly alive to the improvements in mining appliances
might convert into a prosperous property.
Such know ledge comes through the study of the ephemeral
conditions through which mining has passed. A compromise
between or a union of theory and practice, and in such man-
ner as to inculcate the fundamenta of technical knowledge
that will enable the engineer to bring the fancy of expectation
to the level of the facts of experience, is the purpose of the
School of Mines.
524 MANUAL OF MINING.
Fed. Inst. M. E.: On the Value of Photography to Mining Engi-
neers, A. L. Steavenson, I. ; Notes upon a Practical Method of
Ascertaining the Value or Price to be Paid for Zinc Mineral. H. D. Hos-
kold, IV. and V.; Rating of Mines, E. J. Castle, VI. and VII.; Notes
upon a Practical Method of Ascertaining the Value and Price to be
Paid for Zinc Mineral, H. D. Hoskold, VI. and VII.; Photography in
Mines, H. W. Hughes, VI. and VII.; The Colliery Cost-sheets, J. J.
Prest, IX.
Col. Scieniific Sac: On the Estimation of the Capital requisite for
Investment in Mining Properties, P. H. van Dicst, I. 6i.
Ainer. Inst. M. E.: Photographing the Interior of a Coal Mine, Fred
P. Dewey, XVI. 307.
E. &= M. Jou)-.: Design and Handicraft, Elements, W. A. S. Benson,
LVIII. 434; Skeleton Mining Report, B. McDonald, LVIII. 556; Prof-
its in Silver-milling, Editorial, LVIII. 4S1 ; Profit Sharing, Report,
D. F. Schloss, LVIII. 224 and 267; Engineering Methods in Bookkeep-
ing, F. .A. Perrine. LVI. 189; Cornish Tin-mining Photographs, LVIII.
130 to 29S ; Underground Pliotography, James Underbill, July 1897,
125.
Lalce: Sup. Min. Inst.: Sampling Iron Ore, T. C. Mixer, IV. 27.
///. .)//>/. hist.: Daily Examination of Mines, James Freer, i, 1S3.
Mineral Industry : Coal-mine Accounts, W. N. Page, Vol. IV. 205;
Mining Labor and Wages, , IV. 590; Cost of Mining and Depth,
A. C. Lane, IV. 777; The Economics of Coal-mining, W. L. Page, III.
149.
Aiiur. Mfr.: Evaluating Iron Ores, G. Teichgraber, Sept. 1896, 333;
Sampling Iron Ore, T. C. Mixer, Sept. 1896, 370.
Attn. &^ Set. Press : Mines, Miner's Monopolies, J. A. Edman, Feb.
1896, 104, From Mine to Mint, D. K. Tuttle, May 1S97, 453.
Mill. Industry : Buying and Selling Mines, Editorial, Jan. 1897, 10;
Permanency of Mining, Editorial, Jan. 1897, 11.
Engineering Mag.: Determining the Value of an Iron Mine, W. P
Hulst, April 1896, 91 ; Evaluating Iron Ores, Sept. 1896, 333.
Cat. Mineralogist Report : Sampling and Measuring Ore Bodies,
Kirby, 1896. 13th, 679; Cost of Mining Gold, Jolin Hayes Hammond,
loth, 852.
5. 0/ M. <2uarterly : Management of Public Works, E. B. Coxe.
VI. 251 ; Purchasing Silver, Lead and Gold Ores, H. van F. Fnrinaii
XV. I.
Coll. Guard.: Colliery Surface Works, E. B. Wain, Dec. 1894, 1076
Remedies for Mining Damages, Anonymous, 1897, 350; Laws respectui!.;
Ways and Leases, Dec. 1S94, 1025; Nationalization of Mines, lune 1897.
1 144; Metal Mining, J. H. Collins. Mar. 29, 1895,607; The Right of Sm-
face Support in Connection vvitli Mining, Judicial, LXX. 112, 205; The
MINE EXAMINATION. 52$
Wages Cost of Producing Coal, Anon., LXIX, 496; The Legai Meaning
' 155.
APPENDIX.
SAMPLE EXAMINATION QUESTIONS
FOR APPLICANTS FOR OFFICE OF MINE INSPECTOR OR
UNDERGROUND MANAGER.
1. Why are coniced drums necessary in deep shafts?
2. Explain the difference between long-wall and pillar and
room, and the relative amounts of coal produced per acre.
3. In a four-foot seam, 80 fathoms deep, what size would
you make the pillars, having regard to the ultimate extraction
of the greatest quantity of coal combined with safety to the
workmen ?
4. Which requires the largest pillars, thick or thin seams of
coal ?
5. What size and width would you drive entries, gangways,
and rooms ; and what size would you leave ribs and pillars for
safety and economy?
6. Would you mine coal by underhand? Why?
7. What effect does gob, if any, heaped against the side of
a pillar have upon its strength ?
8. Describe how you would employ the _;?/A«^ system for a
20-foot vein of soft coal, when it pitches at 80° from the hori-
zontal.
9. How would you test a steam-boiler to ascertain its
safety?
10. What kind of a hoisting-engine would you consider the
most suitable for a deep coal-shaft?
1 1. Explain fully the advantages in a deep shaft of having a
series of lifts instead of one long lift to the surface — for pump-
ing-engines.
12. Describe some of the best forms of safety appliances.
526
SA&IPLE EXAMINATION QUESTIONS. 52/
13. How would you avail yourself of a voluminous water-
fall at small head for utilizing the power?
14. Give some idea of an electric plant you would suggest
for a copper-mine with 8 levels, 1200 feet deep, and 30 stoping
faces. Ample power to be had.
15. What precautions would you take upon approachmg an
abandoned mine ?
16. If the workings of a mine are approaching the aban-
doned workings of another mine, in which there is a head of
water of 100 feet, how much coal would you leave as a safe
barrier between the two ? And if you should tap it with a two-
inch hole, what would be the number of cubic feet of water
discharged per minute ?
17. In a seam having a dip and rise of i in 6, and the direc-
tion of the plane of the coal being to fall rise, sketch what you
consider a good form of loiig-zvall \\oxV\w ■ - 1- -■ .' - J
3-42,,Sl.iit^
4. 68 Quaitz
Rotltd iron
480
; 46S
Galena. . . .
4. 82 Sandstone
Nickel glance i j68
4 82 Brick
125 to 135
iig.7
85.41099
18 . I to 16
Cerusite.. .
400
5 . 60 Clay
' IS. 7
26.2 to 22.6
Clialcociie.
1 355.7
6.30, Anthracite
Magnetiie.
....... T-,S.fj
6 , 6 1 Bituminous
75 to 83
" 75
781084
73
52-4
44-3
2g.8 to 26. 1
2g,8
28,7 to 27
30.6
42,7
50.5
Specular iron-ore.. '127.4
(> .S4 Cannel
Pv rites.. . .
312
........ 277 . ^
7 . 0^ Liijnite
Barytes. . .
S 07 Oak
Chalcopyrite ' 262 , i
Zinc t/.ende 25'j.o
8. 55 jAsh
8 . 96 Whiir pine. .......
Hematite. .
250.0
8.g6 Yellow pine
38.7
57.8
Limestone.
idS.o
13 3 ' VVocd charcoal ....
25 to 39
89.6 to 57.4
EQUIVALENTS 01
^ FRENCH AND ENGL
[SH MEASURES.
AllBRK\-|-A
rio.Ns. — M. — met
e ; cm. = cenumeter ; G. — gramme ; L. =: litre ; ft. — foot ;
lb. — pound
in = inch ; oz.
= ounce ; dwt. — pennyweight
gr. = grain ; yd. = yard ;
gal = {gallon
; T. = Troy ; A
= avoirdupois ; sec. ::= second ■
sq. — square ; cu. — cubic ;
h. u — heat unit.
I M.
3.28 ft.
I ft. per sec.
= 0.305 M, per sec.
: M,
39.39 in.
1 mile per hour
= 0.447 M.
I ft. =
0.3048 M.
I M. per sec-
= 3.281 ft-
1 in. =
0254 M
1000 M. per hour
= 0.621 mi.le per hour.
t yd
09144 INI.
1000 G. per sq. M
— 0.205 'b. per sq. ft.
I Gunter's c):
ain = 20.1168 M.
1000 G. per cu, M
= 0624 lb per cu. ft.
I mile =
1609.35 M.
I Ib. per sq, ft.
- 4S83 G. per sq. M.
1 sq. M. =
1.2 sq. yard.
I lb. per sq. in.
= yoy,oyj.o G. p'^r sq. M,
1 sq. yd —
0,836 sq. M.
I ton per ft.
= 3.333.333 G. per M.
1 sq. in, "
00065 sq. M.
I gal, per sq. ft.
— 48,905 L. per sq M
T sq. M. =
1555 2 sq in.
I L. per sq. M.
= 0.0204 S^^- per sq. ft.
I acre =
4048 sq. M.
1 G. per L.
= 70-] 16 grs. per ^al.
I cu, in. =
0.0000164 cu. M.
I lb. per cu. ft.
= 160J0 G. per cu. M.
1 cu. ft. —
0,02832 cu. M.
I cu. ft. per lb.
= 0,0624 cu, M. per todo G.
I cu. M. =
1.31 cu. yd.
I degree Fahr.
= 0.5555 deg. centigrade.
. G.
15-43 gr.
I degree Cent.
= 1,8 deg. Fahrenheit.
■ G. =
00022 lb. A.
I lb. per sq. ft.
— column of mercury 0.00359
T. gr. =
0.0648 G.
M. high.
T. lb. =
5760 gr.
I L. of normal ai
r = 19.QS5 grains.
I T. ib. ^
373.242 G.
r G. M.
= 0.-307233 ft -lbs.
lA.lb. -
453 593 G.
I ft. -lb.
~ 138.2 G. M.
1000 G. =
2 lb., 8 oz., 3 dwt
,o.35gr. T.
772 ft. -lbs.
= 106700 G. M.
1000 G. =
2 Ib , 3 oz., 4 dr..
10,473 gr. A.
I calorie
= 3.968 heat-units.
I fluid 0/.. =
0.02957 L.
I heat-unit
= 0.252 calorie.
I quart —
0.9464 I,.
I thermal unit
= 4536 calorie.
T u^lUm =
3,78543 I..
I h.-u, per lb.
= '^■5555 calorie per 1000 Ci.
^ ,'itm 'Sphere
= 760 ^
I.
I calorie per looo
G.= I 8 h.-u, per Ib.
548
MANUAL OF MINING.
TABLE OF HYPERBOLIC LOGARITHMS.
(Base 2.72.)
For Calculations ln' the Expansion of Gases.
X umber. Log
arilhm.
Number.
Log-arilhm.
Number.
Logarithm.
1 .01
009
2. 10
■741
4.60
1.526
02
Dig
2.20
7S8
4.70
547
03
029
2.30
832
4.80
568
04
039
2.40
875
4.90
589
05
043
2. 50
916
5.00
609
06
058
2.60
955
5.10
629
07
067
2.70
993
5.20
64S
oS
076
2. So
029
5.30
667
09
086
2.90
064
5.40
686
10
095
3.00
098
5.50
704
II
104
3.10
131
5.60
722
12
"3
3.20
163
5.70
740
1 I
13
112
3-30
193
5 . So
757
14
131
3.40
223
5 gij
774
15
139
3- 50
252
6.00
791
20
182
3 60
2S0
6. 20
824
25
223
3-70
30S
6.40
856
30
262
3.80
335
6.60
887
40
336
3-90
360
6,80
916
50
405
4.00
386
7,00
945
60
470
4.10
410
7.20
974
70
530
4.20
435
7.40
2
001
80
587
4-30
458
7.60
2
028
90
641
4.40
481
7.80
2
054
2
00
693
4-5°
504
8.00
2
079
INDEX.
AnANDONED mines, approaching,
i86, 2i8, 313, 5:10, 523
Abandonment of mines, 2, I2, 514
Abbot, H. L., 433
Absolute pressure, 490, 534
temperature, 493, 534
Access to workings, 20, 236, 302
Accidents, drilling, 240, 244, 312,
455. 471. 4S7. 499
in anthracite mines, 46, 307, 357
in bituminous mines, 46, 30S,
310, 357
in metalliferous mines, 48, 30S
prevention of, 51, 113, 135, 157,
443
statistics, 309, 357, 35S, 438
Adiabatic curve, 492
Adit, 20, 54. 375, 53°
Adjustable doors, 22;
fan shutter, 260
Advance in tunnels, 186, 477, 479
in shafts, 327, 329, 340, 344, 466
Aerostatic pressure, 243
Aerating gi.aves, 40
Aerial tramways, 177
Aerophores, 323
Affidavit of labor. 15
After-damp, 226, 316
Age of veins, 6
Air-bridges, 287
Air, compressed. 93, 162. 454
compression of, 491, 499
compressor, 206, 381, 49')
consumption of, 225, 231, 454,
466
current, 42, 46, 216, 224, 237, 281
2S7
drills, 327, 341, 379. 422, 452,454
expansion of, 454, 491
friction of, 233, 244. 503
measurement, 283, 491
pressure, 232, 244, 490, 494, 507
Air pumps, 507
receivers, 503
return, 237
Air shafts, 327, 285
valves, 297, 500
velocity of, 225, 243, 281, 504
ways, 24, 225, 236, 271, 274, 281,
2S5, 2S7
weight of, 546
Alignment of shafts, 323, 329
of tunnels, 323, 380
Allowance of air, 231, 281
Aloe rope, 134, 140
Alternating electric currents, 94, 96
Amalgamating ores, 516
American system of mining, 32,
48, 361, 370
American system of tunnelling, 383,
388,476
Ammonite, 425, 433, 437
Ampere, 94
Anaconda mine, 320, 502
Analysis of gases, 221, 224
of powders, 433
Anderson system of tunnelling, 393
Andre, A. A., 424, 459
Anemometers, 281, 283
Animal haulage, 53
.Annunciator, 113, 513
Anthracite coal, 26, 32
mining, 26, 40
waste, 40
Anticlinal, 530
Anti-incrusiators, 65
Apex. 14, iS, 530
Appropriateness of fan to mine,
264
-Aqueous prospecting, 526
Arches in drifts, 366
in tunnels, 392
Ascensional ventilation, 236, 238,
278, 285
Asphyxiation, 224
Assay, 511
Assessment, 15
Atlantic mine, 37, 38, 523
Atlas powder, 3
Atmospheric pressure, 217, 227, 546
549
5SO
INDEX.
Attle, sec Waste.
Augers, 39S
stem, 400, 402
Austrian method of tunnelling, 71,
371. 3SS
Automatic appliances, 106, no
brakes, S3, 102
cut-off, 73
dump, 127, 157, iSl
feed, 461
Axle, 152, 183
Babcock and Wilcox boiler, 64
Back pressure, 530
Bailing tank, iSS
Baird coal-cutter, 481
Baker, 251
rotary, 252
Balance-bob, 193, igg, 530
Band-brake, 63, 84
Barometer, 227, 232
influence of. 227
Barrel blasting, 428
Barrier pillar, 45, 530
Bar timbering, 381, 384, 530
Battery dam, 53, 531
for blasting, 507
for storage, 96
Bearing in, 40, 327. 409
Bearing-in shots, 377, 445, 476
Bedded vein, 4, 7, 17, 29, 511, 531
Bedded-vein mining, 29, 32, 40, 518
Behr's dumping device, 157
Belgian lamp, 295
tunnel system, 381
Bellite, 436
Bench, 10, 24, 49, 378, 3S6, 478, 531
Benzine, 222, 229
Biram, 254
Bit, concave diamond, 467
convex diamond, 467
of percussion-drill, 398, 410, 412,
420, 459
of rotary drill, 411, 449
Bitumen in lead veins, 8
Bituminous coal, 32
Bituminous-coal mining, 31, 40, 43,
HI
Black damp, see Carbonic acid, 224
Black powder, 424
Blacksmithing, 415, 422, 459, 465
Blake pump, 207
Blanket vein, 17, 20
Blasting, 377, 423, 531
off the solid, 26, 409, 485
precautions, 312, 428, 443
Blasting with electricity, 277, 435
a4-l
Blasting with lime, 424
with powder, 427, 443
Bleichert tramway, 178
Blende, 3, 5, 9, 515
Blind drift, 531
Blockholing. 410
Blocking out the mine, 24, 27, 32
Blocking-timbers, 359, 379
Block system of mining, 51
Blocks, 3S8
Blowers of gas, 220, 313, 320
Blowing-fans, 251, 531
Blow-outs, 10, =31
Bob, 193, 199
Boiler, 64, 206
draughts. 245
scale. 64
sectional, 64
water, 63, 65
Bonanzas, 2, 522
Bonneted lamps, 297, 29B
Booming, 10
Bord and pillar, 32, 40
Bore-holes, 187, 314, 396, 472, 479
advance, 186, 313
for prospecting, 12, 323, 386, 472
Borers, 411, 421, 474
Boring methods. 12, 341, 397, 470,
473. 479
Boring-drills, 397, 467
hand, 411
machine. 467, 473
Bowden's wheels, 156
Bowie, A. , 29
Brain's system of drilling, 479
Brake blocks, 84, 127, 166, 167, 177
steam, 84, 112
Brakes, 63, 84
Brandt's borer. 466
Brattice, 237, 286, 289, 531
Breaking ground, 402, 443
Break-through, 26, 41, 237, 287, 531
Breast, size of, 51, 531
workings, 33
Bridle-chains, 139
Brine, evaporating, 29
Broach-bit, 429, 442
Brown's panel svstem, 46
Brunei, M. I., 392
Bucket, ore, 94, 98
pump, 192
water, 187
Buddie, J., 275
Buddie panel svstem, 32, 275
air-splitting, 275
Buggy roads, 34. 152, 531
Bulkhead, 186
Bulkley, F. G., 474
INDEX.
551
Bulling-bar, 427, 531
Bull pump, 194, 531
wheel, 399
Buntons, 331, 531
Burleigh air- compressors, 501
drills, 455
Burro, 177
Butt headings, 26, 531
Butty, 518
Cables, 13, 173
Cage covers, 131
safety. 118, 133, 303, 326
Calculating depth of engine service,
120, 165
haulage capacity, 165, 172, 174
hoisting capacity, 119
power transmission by air, 503
pump capacity, 193, 196, 209
size of engine, IK)
ventilating power, 245 249, 264,
267, 269, 27S
ventilating resistances, 233, 244,
274
work of compressing air, 499
Gallon's lectures on mining, 379, 405
Calorific value of fuel, 58, 226, 248
Calumet and Hecla mine 99, 300,
305, 324
Cambria mine, 321, 371
Cameron pump, 207
Canal tunnels, 21, 1S6
Candle-power of lamps. 299
Candles, 292
Capacity of cars, 143, 171, 324, 326
of engine, 120. 165, 172
of pump, 1 96, 209
of shaft, 118, 132, 139, 324, 326,
337
of tramway, 172, iSl
Capitalizing a mine, 514
Caps, fulminating, 429, 434, 441
in lamp. 228
timber, 355, 370
Carbonic acid in mines, 218, 223,
, 542, 531
Carbonic o.xide, 217,219, 223, 435
Carriage, 24, 118, 129, 152, 358
Cars, 118, 143, 158, 326
Cartridge, lime, 424, 532
safety, 427, 434
soap, 439
water, 424
Car-wheels. 153
Cataract engine, 201, 202, 210
Carbonites, 437
Caves, danger from, 24, 26, 402
Caving system, 32, 40, 50
Cementing shafts, 185, 331
Centre-core system of tunnelling
385
cut system of drilling, 327, 388,
449. 47&
props, 317, 354
Centrifugal force of fan, 264
Centrifugal ventilators, 250, 253,. 264'
Chain, per ton, 486
Chain pillars, 25, 44, 532
Chairs, 133
Champion fan, 256
Champion ventilators, 251
Chance, H. M., 11, 46
Channellers, 28
Chimney draught, 244, 247
Chisels, 39S
Chloride of nitrogen, 425, 426, 430.
Choke-damp, 216, 218, 532
Churning of pump^ 202
Chute, 35, 53, iiS, 129, 532
Clack-piece, 190, 532
Claim, mining, 14, 16
Clanny lamp, 229. 2(}5
Clay iron, 427
mines, 29, 36
Clayton air-comjiressor, 501
Clearance. 500, 532
Cleat, 2(), 238, 445, 532
Clea\age. 20, 40, 354, 404. 409, 429,
444. 481 ^
C. Lc Neve Foster report, ^15
Clip pulleys, 76, 84, 1O7, 169, 171, 178
Closed running fans, 255
Clutches, 112, 134, 173, 177, 183, 460
Coal, 48, 422, 515, 526
beds, 32, 5 12
benches, 10, 24, 49
liorers, 41 1 , 466, 474
consumfjtion, 59, 62, 64, 163, 248,
533
cutters. 4S1, 485
dust, 227, 31S
elements affecting the quality of,
26, 48, 416, 515
in lead veins, 8
mined per fatality, 306
mining, 26, 32, 40, 50, 210, 409,
43'J. 517
physical nature of, 32
terraces, 10
Cobbing, see Sorting.
Coefficient of friction, 271
Collier's tools, 40, 406, 420, 451, 481
Column-pipe, 189, 193, ig6, 533
brass, igo
552
INDEX.
Column-pipe, iron, 189, 102
steel, 189
wood, igo
zinc, 190
Combustion of explosives, 426
Committee on explosives, 435
Compartments, 84, 235, 325
Compensation-joints, 505
Composition of explosives, 425,
437
Compound cylinders, 56, 209, 210,
212, 213
Compressed air, 95, 162, 187, 239,
287, 454, 490, 507
as explosive, 424
efficiency of, 95, 162, 494, 505,
507
loss, 494, 503, 506, 507
transmission of power by, 68, 492,
504, 507
Compression, 533
Comstock mine, 187, 215, 239, 303,
330, 368
Concentration of ores, 516
Concreting shafts, 185, 330, 336,
340
Condensers, 65, 71, 75, 210, 213
Conical drum, 59, 63, 86
Consumption of air, 248, 454. 466
of fuel, 65, 71, 95, 163, 212
of fuse, 431, 442
of powder, 378, 430, 442, 446, 47S
of timber. 35, 48, 350
of water, 64, 100
Contents of coal seams, 45, 53
Continuous system of drilling, 326,
34C', 363. 370
Contract vein, 533
work, 37S, 51S
Cooling air, 492, 499
Cooke fan, 251, 252
Co-operative drainage, 186
Copper ores, 3
mines, 321
Core, 12, 470
drill, 39S, 467
lifter, 470
Corliss engine, 73, 202, 501
Cornish pump, ig6, 201, 209, 313
Cost of drilling, 400, 421, 451, 465,
473
of driving, 23, 357, 382, 465, 476,
517
of electric plant, 165, 442
of framing, 371, 374
of haulage, 143, 152, 157, 162, 172,
182, 546
of hoisting, 62, 117, 140
Cost of illumination, 3CO
of Kind process, 341, 343
of mining, 29, 35, 38, 405, 484, 512,
516, 523
of pumping, 194, 201, 209, 213
of sinking, 327, 339, 341, 342, 346,
383, 466, 517
of timbering, 23, 35, 48, 51, 329,
374. 517, 547
of ventilating, 248, 264
Counterbalance, 56, 57, 13S, 199, 201,
477
Counterpoise, Koepe, 86, go
reel, 86
County of Durham system, 45
Coursing air, 275
Crab, 54, 193, 533
Creep, 44, 220
Crew, B. J., 12
Cribbing, 32g, 339, 371, 533
Cross-cut, 20. 21, 2S7. 289
Croton Aqueduct, 391
Crowbar, 406, 420
Crush, 44
Culm sec Waste.
Curb, 434, 436, 533
Cushier's system of pumping, 203
Cut-off, 71, 73
Dam, 186, 312, 313, 367, 36S
Damps, 217
Danger, symptoms of, 40, 48, 219
Darlington drill, 451, 455
Davy lamp, 229, 293, 294
Day's-pay mines, 518
Dead-work, 22, 25, 5t7, 533
Deane pump, 206
Decking-rages, 70, 132
Depression produced by fans, 255
Depth of holes, 398, 414, 446, 449,
465, 469, 476
of mines, limiting, 48, 239
of shafts, 120, 137, 196, 323, 327
Derrick, 28, 60, ill, 113, 114, 399
Designing of fans. 265
Detaching-hook, lit
Detonation, 426
Detonators, 435, 437
Development by shaft, 12, 22 54
161
by tunnel, 15, 21, 54, 213
of coal-mines. 32, 210, 519
of metal-mines, 32. 2ro. 519
Diagonal ventilation, 237
Diamond-drill. 12, 400, 452, 466,
479
Dick lamp, 296
Differential pulley, 89
INDEX.
553
Diffusion of gases, 228
Dimensions of fan, 259, 266, 269
of gangway, 23, 143
of levels, 21
of shafts, 22, 24, 139, 324
of slopes, 24
Dimension-Stone, 410, 414, 430, 444
Dip, influence of, 9, 22, 33, 40, 43, 53,
171. 358, 379. 3S1, 3S5, 404, 445,
. 534 ,
Direct-acting bolster, 76
pump, 201, 206, 207, 213
Discharge of pumps, 193, 196, 202,
209
Discipline in mines, 224, 225, 348,
428, 518
Discovery, 15
Distribution of air, 84, 96, 97, 272,
279, 285
of power, 165, 182
Divining-rod, 8. 13
Dogs. 135, 206
Dolomite, physical nature of, 380,
445
Doors, circ, 28t)
extra, 224 314
regulator. 277. 2S7
safety, 133, 224, 288, 328
Double-acting pump, 203, 2o5
Double entry, 23, 236, 286, 336
hand-work, 413
Downcast. 240, 327
Drag of air. 232, 244. 249. 534
Drainage, 27. 185, 231, 358
Drifts, 21, 23, 351.. 377, 379, 534
Drill accidents, 95, 399, 455, 471
Drill, steel, 410, 421, 460
tripod, 462
value of, 450, 463, 472
Drilling, 485
by diamond drill. 12, 467, 472,
479
by hand-auger, 411
by power-drill, 327, 340, 377. 384.
446, 461, 479
by spring-pole, 12, 398
efficiency of, 449. 461, 473
holes, 12, 187, 324, 396, 444, 449,
462, 472
progress, 400, 412, 465
Drinkers, H. W., 395
Drums, 80, 86, 137
Dualine, 432
Dumb-channel, 246, 247, 534
Dump, 21, 70, 534
Dumping, 126, 127, 152
Duplex compressors, 496, 502
holsters, 82, 86
Duplex pumps, 209, 212
Dust explosions, 315, 318, 319
Duty, 184, 196, 212, 534
Dynamic units, 212, 245
Dynamite, 432, 3:1
storage of, 434
Economizers, 65
Effective, illumination. 299
93, 264,
174
434 445
jiower, 69, 83, 95,
Efficiency of compressors,
504, 506
fan, 261
of drills, 449, 461, 474
of electric appliances, 93,
of explosives, 439. 442
Eissler, Manuel, 430
Electric coal-cutter, 98, 481
drill, 95, 98, 466, 470
firing, 95, 311, 317,
fuse. 439
hoister. 95, 99
lamps, 300
machines, 485
motor, 94, 165, 502
prospecting. 525
pum p, 98, 165
signalling, 95. 113. 174
terms, 96
transmission of
165
units, 96
wires, 95, gS
Endless cable, 169, 171
chain, 172, 173
rope, 161, 167, 172, 177
End-lines, 16
Engine haulage, 161, I'ly, 172
horse-power of, i 19, i'"i5
house, 69
plane, 163
underground,
2I3,'"328
English system
and French measures,
547
Entry, iS, 21, 45
double, 23, 236, 324
single, 235
Equivalent orifice, 233. 262
of fan. 262
Escapements, 135, 237
Estimating the tonnage of seams,
the value of a mine, 513
Examining a vein, 11
a mine, 510
Exhaust-fan, 98, 253
Expansion bits, 449
161, 162, 169, 171,
(.>f tunnelling , 3S3
3S3- 3S6,
554
hXDEX.
Expansion joints, 505
Expansion of air, 241, 491
of steam, 72, 243
Exploitation, 23, 534
Exploratory work, 10
Explosions, 216, 222, 226, 298, 314
guidance after, 316
precautions against, 316
Explosive, compressed air, 424
definition of, 424, 430
gas, 223
mixtures, 222
use of, 26, 423, 428
Explosives, 423, 430
accidents with, 434, 443
fiame from, 225, 424, 426
gases from, 424, 427, 431, 443
storage of, 434
External friction bolster, 82
Extinguishing fires, 320
Eye, see Pick.
Fabry fan, 251, 252
Face, 30, 45, 514. 534
Face-entry, 26
Fahrkunst, 304
Faintingin shaft, 310
Falls of roof, 46, 48, 308, 483
False walls, 6
Fan chimney, 260
velocity, 265
ventilation, 255, 267
Fans, 98, 249, 255, 267
Fault, 26, 46, 312, 535
Feather, 452, 511
Federal mining laws, 14
Ferranti electric system, 97
Fiery mines, 32, 46, 222
accidents in, 312
precautions in, 46, 317, 329, 424,
427
Filling method, 31, 40, 49, 362, 542
Fire, causes of, 69, 162, 317
Fire-damp, 220, 226, 238, 328, 535
detection, 229
in mines, 9
Fire-setting, 405, 434, 535
Firing, barrel system, 428
electric, 95, 439
needle, 427
First motion engine, 77, 430
Fissure veins, 5, 17, 479, 511
Flame from explosive,
Flameless explosive, 424, 426
Flat rope, 86, 137, 140
stopes, 35
Fleuss diving apparatus, 321
Float, II, 535
Flooding mines, 164, 320
Floor, 6, 48, 535
Fly-wheel holster, 71
on air-compressors, 494
pump, 172
Foot-wall, 51, 352, 535
Force of fans, 251
Force-pump, 194, ig8, 201, 207
Forcite, 432
Forepoling, 333, 363, 389, 535
Forfeiture, 15
Forge, 418, 421
Formula for air-compression, 391
for conical drums, 87, 89
for engine capacity, 119, 121, 133
for equivalent, 233, 263
for engine cylinders, 120, 545
explosives, 446
fan ventilation, 263, 267
mine valuation, 516
motive column, 244
pipe friction, 102, 273
pumps, 193, 196, 207, 546
shaft capacity. 1 18
stulls. 352
\'entilation, 242. 245. 272, 279
weight, volume, and tension of
air, 242, 244, 24S, 491, 541
Foster, C. LeNeve, 379, 405
Foundations for machinery, 21, 71,
193, 199, 210, 516
Frames, no, 114, 193, 349, 354, 358,,
370, 373
Framing arches, 359
machines, 36S, 374
tools, 374
Franklin Mine, 428
Free air, 382
French and English measures, 547
French measures, 491
Friction, 113, T14, 121, 161
coefficient of, 272
gear, 76, 82, 84, 167, 178
bolsters, 76
of air, 245, 274, 503
of axles, 152, 158, 1S3
of cars, T19, 138, 15S, 165, 174
of electricity, 98
of shafts, 290, 327
of water, 213
Friedensville Mine, 1S6
Frith's coal-cutter, jPi
Frost, Benjamin, 337
Fuel consumption, 65. 71, 73, 163,
210, 248
value, 65
Fulminate, 427
Furnace ventilation, 246, 261
INDEX.
555
Fuse, electric, 337, 441, 452
safety. 428, 434, 442
Fusee, 8g
Gad, 410, 535
Galena, 3, 429, 547
Galleries, driving, 24, 48, 389, 465
dimensions of, 23, 357, 3S0
timbering of, 24, 373, 479
Gallows- frame, 62, no, 113, 535
Gangue, 5, 36, 43, 515, 535
Gangway, 24, 140. 3S0, 535
centre-props, 354
Gangway, driving, 316, 357, 398
466
grades, 25, 160
timbering of, 354. 362, 389
Gas. causes of the evolution of,
40, 215. 220, 221
detection of. 222, 224, 229
in mines, 25. 48
Gases, 215, 217, 292
explosive, 219, 221, 223
extinction of flame, 223
from decomposition. 218, 224
from explosions, 226
from powder combustion, 219, 424.
427, 431. 443
Gasfi veins, 6, 29. 511, 535
Gates ore bin, 33. 152
Gauge-pressure. 174, 231. 3S2, 535
of track, 153
Gelatine, 433, 435
Geological maps, it, 375, 400
report, 395
theories, 5, 8, 400
Geordie lamp, 295
German system of tunnelling, 3S3
Giant powder, 433, 454
Goaf, 4r, 219. 220, 227, 280, 312
Gob. 3b, 40, 219
road, 40. 2S6, 359
Gobbing up, 53, 359, 535
Gouge, 444, 535
Grade of drift, 21, 25, 35, 156, 160,
163, 166, lb9
Granite, ph)sic;.l nature of, 380,
429, 44b, 473
Gravity, taking advantage of. 33,
53, 70, 161, 166, 177
roads, 35, 70, i6t, 179
Gray's lamp, 229, 296
Greathead system in tunnelling,
395
Guibal fan, 251, 255, 261, 267
Guides, 112, 127, 536
Gun -boats, iiP. 127, 536
Gu n-rotton . 425
Gypsum beds, 29, 46
Haase's system, 345
Hall, Wm., 358
Hallidie tramwa;'. 179
Hammer. 415
and wedge, 406, 409, 419, 424
Hand vs. machine, 158, 326, 348,
379. 480
borers, 411, 421
Handling the product, 33, 118, 12S,
131, 152
Hanging-wall, 352
shafts, 22, 327
Hardening steel, 417
Harrison coal-cutter, 481
Haulage, 24, 33 53, 143, 15S, 161,
i6g, 382
ways, 25, 30, 41, 151, 158, 160
Head-gear, 62, in, 114
Heading, 26, 40, 536
Heath and Frost's lamp, 229
Heat-unit, 210, 226
Height of frames, 56, no, 114
Helve, 407, 421, 536
Hemp rope, 136, 139
Henwood, W. J., 27
Hepplewite-Gray lamp, 229, 296
Hercules powder, 433
High explosive, 425, 443
Hitches, 330. 536
Hoister, best type of, 82
Hoisting, 36, 58, 115
conveyances, no, 118
economy, 36, 62, 71. 73, 94
engine, 73, irg
rope, 115, 136
speed, 59, 75, no, 118, 124, 139
Holing, 36, 40, 409, 4S0, 536
Hollenback shaft, 332, 34C)
Hooks, III, 124
Hoosac Tunnel, 337, 358, 455
Horse haulage, 62, 160, 53b
power. 62. 65, 98, 119, 174, 183,
213, 245, 253, 278, 322, 454
fforses in veins, 354, 511
llfirse-power in ventilation, 264,
27S
Housing of plant, 68, 117
Howe. H. M., 417
Howell's auger, 41 1
Hopton, 254
H-piece, 196, 201, 536
Hudson River Tunnel, 394
Hungarian system of pumping, 187
Hurdy-gurdv, 100
Huson tramway, T79
H'dr.-iillir borer. 466, 474, 483
55&
INDEX.
Hydraulic engine, 187, 194, 213
feed, 46S
mining, 29, gS
pumping, 187, 213
ram, 187
shield, 392
wedge, 410, 423
Hydraulics, 100, 187
Hygienic measures, 216, 521
Hyperian logarithms, 54S
Illuminaiion, 85, 193, 222, 292
Inclined planes, 166, r68, 179
Inclines, 22, 536
Incrustations, 64
Indicators, 112, 213,536
Ingersoll coal-cutters, 481
compressors, 499
drills, 455, 457
Injured, treatment of, 457
Inspirators, 65
Intake, 236, 285, 536
Internal friction hoisters, 80
Intersecting veins, 6, 16, 26
Iron in mines, 318, 334, 340, 356, 363,
373.415. 546
in shafts, 185, 330
in tunnels, 364, 392
lining, 330, 339, 364, 392
mines, 28, 33, 44, 350
ores, 3, 32, 515
props, 356
shield, 392
tubbing, 185
tubing, 189, 414
Isothermal curve, 492, 499, 505
Jacketed cylinders. 17, 75, 210
Jars, 342, 397, 536
Jaws, 26, 41, 278, 2S5
Jeffrey coal-cutter. 4S1
Joints in stone, 2O, ;. 54
of pipe, no, 189
of timber, 331, 351, 355, 368
Joule, 98
Journal friction, 121, 183
Jumper, 398, 412, 452
KlHBLE, 124, 536
Kicking down a hole, 396
Kind-Chaudron process, 341, 398
plug, 403
Kirving, see Underholing.
Knight wheel, no
engine, 213
Knowles pump, 204, 207, 213
Knox's system, 430
Koepe's system of '.\ in ding, 86, 90
Kutter's formula, 102, 273
Labor problem, 413, 480, 517
hand, 324, 330, 358, 379, 409.
520
machine, 379
Ladders, 201, 302, 521
Lagging, 330, 359, 363, 481
Lake Superior mines, 38, 44, 157,
234
methods, 28,44, 207, 323, 327, 333;
350, 368, 410, 465
Lamps, 215, 225, 229, 293, 294, 31-,
516, 518
Landings, 70, 134, 135, 372
Landscape rock, 4
Laths, 389, 392, 537
Laundry-box, 193. 198, 537
Laws. State mining, 14, 216, 260,
236, 424, 427
Laws U. S. mining, 14
Lawton, C. D., 454
Lead ores, 3
Leasing mines. 520
Lechner coal-cutter, 481
Leffel wheel, 100
Legg coal-cutter, 4S0
Lemiele fan, 25t, 253
Length of fan, 266
Leonard, H. W., 98
Leschot, W. M.. 466
Level, 21, 379, 537
dimension of , 23
maintenance, 24, 30, 362, 364
where placed , 25
Levels, distance between, 24
Lewising, 429, 444, 452
Lidgerwood hoister, 84
Lime cartridges, 424
Life, loss of, 53
of a mine, 21, 53, 513, 521. 523
of rope , 134, 138
of timber. 334, 349
Lift, length of. 24, 41, 50, 197, 237,
537
pumps, 187, T93
Lignite, 65, 213
mines, 40
Limestone, physical nature of, 414,
444. 446
Lincke coal cutter, 481, 4S3
Line of least resistance, 443, 446
Link-motion engine, 82
Lippman's drill, 346
Loading and unloading, 33, 41, iiS,
126, 129, 152
Location of machinery, 21, 70
mining, 14, iS, 537 '
INDEX.
557
Location of sliafl, 20, l6l, 326
of tunnel, 20
Locked wire rope, 137
Locomotive, electric, 165
pneumatic, 165
steam, t62
Lode, definition of, 5, g, 13, 18,
537
Logarithms, Hyperbolic. 548
Long-fiole process, 346, 363, 370
Long tunnels, 186, 323, 383. 442, 471,
475
Long-wall, 32. 36, 40, 44, 286, 293,
409, 430, 4S3, 537
Lubricants, 158, 213. 502
Machine designing, 21, 63, 71, 15S,
161, 174, 182, 201, 210, 267, 521
vs. hand-work, 158, 324, 327, 329,
341. 372
Magic wand, 8, 13
Magneto machine, 441
Man-engine, igg, 201, 304, 521, 537
Manganese ores, 4
Man-hole, see Mill-hole.
Manometric depression, 249, 255,
261, 267. 272, 274
Manual haulage, 158
labor, 409, 517
Mapping, 11, 358, 381, 3g5
Marsault lamp, 2g5
Marshall coal-cutter, 481, 483
Marsh-gas, 220
Masonry in mines, 186, 336, 340, 363,
367,' 372, 380, 3g4
Mather and Piatt boring system,
39S, 473, 4g7
Measuring air, 231, 247, 277
velocity, 283
Mechanical ventilators, 230, 250
Melinite, 462
Mercury veins, 4
Metal, mines, 216, 308
Methods of mining, 31-53, 523
of timbering. 42, 52
of tunnelling. 362
Mica, 4
Mill-hole, 27, 34.36. 43, 129, 373.
537
run. 537
Milling processes, 515
Mill-run, 481
Mine cars, 116, 143, 15S
definition of, 3
fires, 9, 6g, 115, 117, 162
gases, 25, 40, 215
Mineral, 3, 511
Mine resistance, 262
Miner's inches, 213, 537, 546
Miner's indifference to danger, 225.
309. 42g
tools, 8, 13,90, ig3, 348, 373,407,
411. 414, 421, 426
Mining, economy of, 2, 22, 25. 28. 2g,
46, 118, 126, 139, 156, 158, 215.
405, 413. 430. 434, 443. 445. 454.
495. 512. 518
in soft ore, 32, 42, 52
in thin seams, 32, 40, 355, 4S3
in thin veins, 32, 35
in thick seams, 31, 44, 46, 370
in thick veins. 31, 48, 359, 370
laws, 14, 216, 236, 260, 424, 427,
53S
Mining claim, 14, 16
retreating. 32. 40, 42, 49, 538
Moil, 410, 538
Monongahela system of mining, 51
Moss-box, 344, 403
Motive column, 231, 233, 244, 249
power. 35. 94, 95, 159, 165, 182
Mueseler lamp, 295
Mule efficiency, 160
Mule haulage, 35, 159
cost of. 160
Musconetcong Tunnel, 442, 476
Naked lights, 223
Narrow work, 41, 538
Native metal, 2
Natural gas, 221
gas mains, danger from, 225
Natural slope of ore, 33, 53
ventilation, 216, 239, 240
Needle blasting, 427
Nickel ores, 4
Nitro-glycerine, 425, 426, 430, 538
loading with, 434
manufacture, 431
storage of, 434
Nobel, W., 430
Norris, R. Van A., 15S, 259
Norwalk air-compressor, 4g9
Occi.fDED gases, in coal, 2ig
escape of, 221 . 223
Ohm, 94
Oil, illuminating, 222, 292
prospecting for, II, 402
Oil-well rig, 398
torpedoes, 402
Oilers, self. 144, 152, 156, 158
One-hand work, 413
Ontario mine, 186
Open-ninn'ng fans, 254
Ore dc] s l^oti. 7, 17, 538
558
INDEX.
Ore definition of, 3
in sigiit,. 512
reserves, 24, 512
shoot, 7, 48, 513, 538
treatment of, 5.12, 515
Outbursts of gas, 220, 314
Outcrop of coal, 10
of veins, m, 14, 18, 538
Outlet, double, 23, 237
single, 24, 235, 538
Output, 95, 53S
0\'ercast, 289
Overhand method, 34, 36,
Overloaded engines, 62
Overwinding, 90, ill
370
Pack-wall, 40, 363
Panel system, Brown's, 32, 46, 538
Buddie's, 32
Partings in coal, 40, 49, 64, 511, 53S
Patenting a claim, 16
Paying men, modes of, 51S
Pay-streak, 6, 25, 33, 538
Peat-mining, 29
Pelton wheel, 102
Pentice, 32S
Percussion-drill, 327, 341, 381, 422,
452
Perforators, 474
Petroleum, monograph on, 12, 292
Phosphate rock, 4, 29
Photophobia, 299
Pick, 406, 420, 452, 538
Pickets, spilling, 391
Pick-mining, 486
Picric acid, 425
Pieler gas-detector, 87, 229
Pike, see Pick.
Pillar and galleries, 48
Pillar and stall, 32, 40, 45, 221, 293
Pillars, robbing of, 43, 48, 52, 221
sizes of, 41, 45, 46, 48
waste in recovering, 42
Pinch, 6, 26
Pipe, 53S
Pipes, brass, 190
iron, 189, 197, 402
steel, no, 189, 505
wood, 190, 402
zinc, 190, 402
Piston-speed, air, 454, 465, 502
pump, 192, 194, 207
steam, 120, 174, 194
Pitman, 193, 539
Plane, 69, 161, 166, 539
Plant, mining, 21, 63, 72, 161
Platform, 132, 135, 166
Plats, 132, 134, 158, 201, 328, 373, 539
Pleasant, Gen. H., 479
Plunger, 187, 194, 199, 204, 539
Pneumatic system, 95, 162, 187, 339,
382, 454. 504
Poetsch sinking system, 339, 346,
347, 363
Pole-pick, 407, 539
Poling, 330, 363, 389, 539. 541
Poppet-valves, 500, 539
Porphyry, physical nature of, 404,
445. 446
Post and stall, 45, 376, 539
Powder, 215, 428, -13S
accidents with, 434, 443
consumption of, 26, 46, 430, 442,
487
Powder, charges of, 428
manufacture, 427, 431
storage of, 373, 434
Power drills, 327, 341, 3S1, 422, 452,
539
distribution, 84, 97, 98, 165, 1S2
Precautions against fire, 69, 117, 216,
219, 316, 341, 424, 427
Preparatory work, 24, 34S
Pre-release, 539
Preservatives for rope, 136, 13S
for timber, 190, 335, 349
Pressure of air, 244, 3S2, 454, 494
of explosive gas, 220, 227, 426
of steam, 64, 82, 196, 207
Priestman oil-engine, 214
Product of coal seams, 45, 53, 512
mines, 46, 381, 512
Prop, 37, 40, 350, 360, 485. 538
Prospecting by boring, 12, 324, 379,
402, 415, 472
by wand, 8, 13
by witchery, 13
in massive rock, 10
in stratified rock, 11
surface, 10, 538
Pump-bob, 193, 199
Bull, 192
Cook, 193
Cornish, 194, 201
duty of, 194, 196
electric, 98
force, 1S9, 198, 206
hydraulic, 1S7
lift, 1S9
rod, 189, 193, 199
rotary, 213
sinking, 192, 206, 338
station, 201, 208, 373
steam, 203, 207
Pumping-engine, 208, 213
in relays, 201, 209, 210
INDEX.
559
Punch-drills, 12, 396
Puzzolana mining, 29, 46
Pyrites. 2ig, 473, 4S3, 515
Pyrogl)'cerinu. 430
Quarry, 27, 76
Quarrying dimension-stone, 28, 410,
414, 430. 444. 452
objections to, 28
Quartz, physical nature of, 404, 445,
446
Quick ground, 333, 33S, 368, 4S2, 538
powder, 425, 443
water, 2og
Rackarock, 433
Rafter timbering, 540
Rail, 23, 157
sizes of, 157, 163, 546
way, 23, 38, 157, 162
Raising water, 185, i83
Ram, 187
Rand drills, 455, 457
compressors, 496, 500
Raymond, R. W., 18, 516
Reamers, 344, 414
Reciprocating blowers, 253
Reels, 86, 137
Refrigeration, 347
Regulator doors, 28S
Relative merits of furnace, 216
Rendrock, 433
Reserves, 24, 30, 47, 512
Resistance, 232
Retreating mining, 32, 40, 42, 49
Reversible engine, 76
Rib, 24, 40, 51, 540
Rifled holes, 399, 460
Rift in stone, 439
Right-angled long-wall, 40
Rise, to the, 24, 33, 35, 45, 51, 63
Rivet-pipe, no, 189
Robbing pillars, 43, 44, 52
Roberts lamp, 221
Roburite, 437
Rock-drills, 326, 341, 389, 422, 455
Rock in place, 16, 17
Rogers pump, 207
Roof, 5, 37, 40, 347, 358, 388, 511,
540
falls, 40, 310, 347
varieties of, 40, 44, 347, 351
Ro.jm, 40, 45, 349, 371, 373, 540
Root blower, 251, 252, 253
boiler, 64
iRope, 115, 127, 136, 182
drilling, 472
Rope, flat, 86, 137, 140
haulage, 158, 161, 169, 181
preservation, 115, 136, 13S
round, 79, 136
sockets, 139, 174
tapered, 86, 119, 138, 140
transmission of power, 69, 84,
95, ti7. 161, 182
Rotary-bar. 486
Run, 35, 45, 540
Run of mine, 486
Rupturing effect of explosives, 426
Rziha, M. A., 328, 381, 425
Safety apjiliances, 106, in, 112,
134. 135. 225
boiler, 64
cage, 133, 540
catch, 106, 136
chain, 126, 137, 139, 225, 327
doors, 135, 225, 289, 328
e.xplosives, 436, 438
lamp, 225, 294, 540
measures, 20, in, 1^,4 216, 330,
348 ^
Salt mining, 28, 46, 334, 339 3fj2
Sampling a vein, 511
Sand pump, 12, 342, 346, 39b, 540
Scale in boiler, 64, 540
Schiele fan. 251, 255
Schmidt's rule, 27
Schram's drill, 455, 459, 466
Schwartz, Kerthold, 427
Seams, 40, 53, 380
influence of, 40, 356, 371), 380. 404,
409, 445, 447
Seasons, influence of, 241. 249. 2'jo
Second Geol. Surv. of Penn., 11, 42
Second-motion engines, 77, 121
Seed-bag, 344, 403, 540
Self-acting plane, 161, 166, 179
Self-oiling wheels, 144, 152, 156. 158
Self-recorder for fans. 260
Self-registering gauge, 260
Selvage, 5, 540
Separate ventilation, 238
Sergeant drill, 455, 457, 481
Serlo, Dr. A., 414
Serpentine hook, in, 124
Shaft, 12, 20, 185, 215, 540
auxiliary, 23, 166, 186, 383
capacity of, ii8. 132, 139, 325, 333
compartments, 84, 131, 221, 236
equipment, 117, 127, 157, 323
pillars, 25, 329
rectangular, 324, 333
round, 326, 335, 340, 342
shape of, 324
56o
INDEX.
Shaft, sinking, 323, 338, 344, 383,
426, 449, 466, 479, 521
site, 20, 70, 161, 323, 327
size, 139, 323, 327
timbering, ir8, 126, 132, 323, 329,
373. 3S9
ventilation, 161, 247, 324
Siiarpening tools, 412, 460
Shaw's gas-detector, 229
Sheave, 62, 115, 137, 167, 178, 182,
540
Shell-pump, sec Sand-pump.
Shift-options, 518
Shifts, 521, 541
Shode, II
Shoot, ore, 7, 541
Shooting in brittle ore, 429, 444, 449
Shovels, 156, 406
Shiite, 33, 34, 53, 118, 128, 541
Shutter on fans, 256, 260
Side line, 14, 1 7
Sigillari£E, 309
Signals, 70, ill, 114, 317, 545
Sills, 25, 52, 137, 312, 336, 554, 541
Silver Islet mine, 472
Silver ores, 4, 9, 415
Simultaneous firing, 337, 445, 474
Single-acting engine, 1S9, 192, 39S
entr}^ 23, 236, 237, 323
hand work, 413
Sinking engines, 71
continuous process, 326, 472, 479
Haase's system, 344
in running ground, 337
Kind-Chaudron's process, 340
Mill's, 345
Poetsch's sj'Stem, 472
pump, 194, 199, 204, 337
Triger's system, 340
Siphon, 214
Size of beds, 512, 515
cars, iiS, 143, 325
drums, Sd, 120, 137
shaft, 131, 230, 325
timber, 329, 351 , 357
Skids, 12(1
Skips, 118, 127, iSS, 325
Slack, 49, 50, 65, 541
Sledge, 413, 415
Slickensides, 6, 511, 541
Slide-valve, 70, 74
Slitter, see Pick.
Slope, 20, 121, 541
cage, 134, 188
car, 127
carriage, 24, 118, 129, 152,357
openings, 20
railway, 126, 136
Slope, tramway, 130
Slow powder, 425, 447, 544
Sludger, 12, 24, 342, 398, 541
Smokeless powder, 438
Snap-hooks, iii, 124
Sobrero, M., 430
Soft ground, drifting in, 48, 52, 348,
362, 3SS, 391, 394
mining in, 32, 48, 367
sinking in, 333, 341
timbering in, 40, 49, 367, 386
Sorting ore, 34
Spades, 406
Speaking-tubes, 113
Speed of drilling, 342, 343
haulage, 158, 181
hoisting, 59, no, iiS, 126, 312
pumping, 194, 199, 201
register, 260
ventilating current, 225, 242
Spence's metal, lyo
Spilling, see I^olling.
^ laths, 367, 3S9, 392
Spiral weld tubing. 189
Splicing rope, 142, 174
Splitting air-current, 51, 237, 274,
275, 277, 28S
Spontaneous combustion, 40, 2ig,
313
Spoon, 412, 414, 541
Sprag, 155, 157, 350, 541
Spring-pole drilling, 12, 398
Spudding, 399
Square setts, 32, 42, 51, 361, 367,
542
work, 32, 46
Squeeze, 4S, 220, 542
.Squib, 428, 449
Stables, underground, 160, 319, 349,
372
Stalls, 47
Standard coal seam, 32
Stand-pipe, 1S7, 196
Steam as extinguisher, 320
boiler, 64, 204
brake, 84, no
coal, 65
condenser, 65, 71, 75
expansion, 73, 210
jet ventilation, 250
pressure, 64, 82, 196, 209, 382
pump, 203, 206
Steel, black diamond, 413, 420, 421
definition of, 417, 420
Jessup, 413, 421
rope, 136, 140
tools, 412, 417, 421, 460
Stephenson lamp, 295
INDEX.
561
Steuberiville system, 50
Stockwerke, 4, 6, 542
Stoop and room, 47
Slope, 24, 36, 51, 380, 542
height of, 25, 517
Storage of powder, 372, 434
battery, 166
Stowing, sc'i; Filling.
Strike, 50, 51, 542
Stripping, 27
Struve fan, 255
Stull, 34, 197, 330, 351, 542
Stump pillars, 25, 46, 51, 542
Stythe, see Carbonic acid.
Suction-pipe, ig2, igg, 201, 208, 215
Sulphuretted hydrogen, 219
Sump, 23, 187, 209, 542
Surface buildings. 6g, 71, 415, 516,
522
examination, 12
Salting, 467-484
Surface plant, 21, 57, 71, no, 127,
167, 193, igg, 201
subsidence, 41, 43, 53
tramways, 167, 177
Sutro Tunnel, 187, 361, 380
Swallow, Dr. G. C, 310
Synchronous firing, 337, 3S0, 445,
474
Systems of drilling, 12, 3S0, 398,
443. 445. 474. 476, 479
haulage, 161, 165, 172
mining, 31-53, 3S0, 523
Tables of air losses, 503
of air-compression, 491, 500, 506
of casualties, 310
of friction losses, 395
of steam expansion, 120
of values of explosives, 426
of weight of ore, 548
Tail out, II
Tail-rope haulage, 71, 161, i6g, 173,
543
hoisting, 71, 86, 8g
Tamping bar, 427, 543
material, 426, 43T, 438, 44g
Taper rods, 197
rope, 86, iig, 138, 140
Tappets, 206, 455
Tapping holes, 1S6
Telephones, 113
Telescopic joint. 192
Temperature of rleep mines, 239
Temper-screw, 398
Tempering steel, 418, 421, 543
Tension-wheel, 172
Terchloride of nitrogen, 425, 430
Tesla's electric system, 96
Testing for gas, 229
Thames Tunnel, 383, 392
Thermal unit, 212
Thickness, minimum, minable, 32,
512
of pipes, 197
Three-wire system, 96, 99
Throughs, 26, 45, 237, 284, 543
Thrust, 48
Tight ground, breaking, 444, 445,
474
Tilly Foster mine. 28
Timber joints, 330, 351, 358, 368
preservatives, 334, 349
props, 40, 313, 350
Timbering collars, 354, 358, 369
cost of, 35, 48, 5T, 329, 349, 490,
519
gangways, 357, 378, 383, 389
iron for, 313, 333, 356, 364
levels, 355, 373, 380, 389
methods of, 38, 40, 48, 350, 361,
370, 385
principles of, 317, 349, 351, 362,
364, 512
rooms, 42, 52, 350, 371, 373
shafts, iiS, 126, 329, 372
slopes, 336, 346, 373
slopes, 38, 52, 349, 360, 371
Tin ores, 4
Tipple, 126, 158, 519
Tonite, 433
Tools, 8, 13, 90, 193, 311, 407, 417,
426, 429, 452
Top roller, 289
Traction, animal, 35, 159
engine, 164, 167
locomotive, 162, 163, 105, 546
manual, 158
Tractive force, 158, 164
Tramway. 23, 36, 38, 138, 157, 158,
167, 178, 543
Transfer platforms, 130, 132, 133
Trap-doors, 133, 160, 543
Trapper, 160
Tra\'elling wavs, 135
Traverses, 4, 31, 50
Treatment of asphyxiation, 224
Trenchers, 28, 452
Trepan, 342
Tribute, 520, 543
Triger's method, 341
Tub, 59, 124
Tubbing, 185, 330, 337, 340, 543
Tubes, 402, 414, 467
recovering, 403
Tubing wells, 402, 473
S62
INDEX.
Tunnel, 12, 361, 395, 543
dimensions of, 360
long, 186, 324, 378, 384, 388, 443,
475. 477
openings by, 381
progress, 380, 381, 426, 476
site, 20, 21
timbering of, 374, 378
ventilation, 161, 215, 380
Tunnelling methods, 380
Turbines, 98, 102
Two-hand work, 413
Two-wire system, 96
Typical air-way, 281
Ultimate source of mineral, 8
Underground chambers, 349, 373
currents, 185, 404
engines, 161, 167, 169, 172, 327
traffic, 24, 53, 143, r6i, 174
Underhand mining, 31, 38, 378
work, 407, 543
Underholing, 40, 52, 409, 480
Upcast, 45, 240, 247, 322, 326
Upraise, see Mill-hole
U. S. mining laws, 14
V BIT, 344
Value of a mine, 512, 521
Valves of air-compressor, 500
of drills, 452, 454
of engines, 72
of pumps, 190, T95, 201, 206, 207,
215, 455
Van Diest, P. H., 516
Vein, 3, 13, 16, 525. 543 .
definition of, 5, 9, 13
formation, 7, 10, 16
Velocity, 243
of fan, 259
of haulage, 158, 160, 163, 166, 171,
172, 173, 181, 281
of hoisting, 55, no, 118, 126, 139
of pumping, 194, 201, 202
of ventilating current, 162, 225,
243, 281
Ventilating current, 37, 40, 45, 281
ways, 24, 235, 276, 280
Ventilation, 37, 40, 51, 162, 279, 333,
406
current, 245
during sinking, 215
fan, too
friction, 40, 231, 233, 245, 249,
274
in coal mines, 216, 275
in metal mines, 216, 238
methods. 237, 246, 372
Ventilation, natural, 240
of breasts, 286
of tunnels, 161, 323, 380
paradox, 233
pressure, 224, 277
splitting, 45, 276
velocity, 162, 277, 281
V friction, 77, 82, 167, 169, 171
Voltage, 96
Volume of air, 97
Vulcanite, 433
Waddle fan, 251. 254
Wages, 518
Wagon-breast, 34, 543
Walker, 251
Wall, 5, 347, 352, 544
Wall-plates, 544
Walling back-water, 186, 312, 367
drifts, 273, 313, 382, 390
shafts, 185
Wasmuth system, 45
Waste for filling, 40, 544
in coal, 41
in mining, 41, 46, 50, 53, 126
Water bailers, 188
cartridges, 424
consumpti