Cornell University 
 Library 
 
 The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924080100872 
 
The Use §f Explosives 
 in Making Ditches 
 
 Published by 
 
 The Institute of Makers of Explosives 
 
 103 Park Avenue, New York City 
 
Hntt (College of ^Agriculture 
 
 At QJorneU IttluerBttB 
 
 .Jttjara, N. % 
 
The Use of Explosives 
 in Making Ditches 
 
 Published by 
 
 The Institute of Makers of Explosives 
 103 Park Avenue, New York City 
 
 Copyright 1917 by 
 The Institute of Makers of Explosives 
 
INSTITUTE 
 
 OF 
 
 MAKERS OF EXPLOSIVES 
 
 Organized July 15, 1913 
 
 MEMBERS 
 
 AETNA EXPLOSIVES COMPANY, Inc. 
 New York, N. Y. 
 
 ATLAS POWDER COMPANY 
 Wilmington, Del. 
 
 AUSTIN POWDER COMPANY 
 Cleveland, Ohio 
 
 THE GRASSELLI POW^DER CO. 
 Pittsburgh, Pa. 
 
 E. I. DU PONT DE NEMOURS & CO. 
 Wilmington, Del. 
 
 EGYPTIAN POWDER COMPANY 
 East Alton, 111. 
 
 EQUITABLE POWDER MFG. CO. 
 East Alton, 111. 
 
 EXCELSIOR POWDER MFG. CO. 
 Kansas City, Mo. 
 
 THE GIANT POWDER CO., Cons. 
 San Francisco, Cal. 
 
 HERCULES POWDER CO. 
 Wilmington, Del. 
 
 ILLINOIS POWDER MFG. CO. 
 St. Louis, Mo. 
 
 KING POWDER COMPANY 
 Cincinnati, Ohio 
 
 SENIOR POWDER COMPANY 
 Cincinnati, Ohio 
 
 STANDARD POWDER CO. 
 Philadelphia, Pa. 
 
 UNITED STATES POWDER CO. 
 Terre Haute, Ind. 
 
INTRODUCTORY 
 
 THIS bulletin is published by the Institute of Makers 
 of Explosives. It is not intended to sell anything, 
 or in any sense as a piece of sales literature, but as a 
 manual or handbook for those who drain land and make 
 ditches, and possibly as a textbook for students of agri- 
 culture and rural engineering. 
 
 Ever since the blasting of ditches has become 
 standard practice there has been need of some book of 
 reference containing the essential facts about the use of 
 explosives in the making of ditches, eliminating untried 
 theory and conflict of opinion so often found in less 
 complete publications on the subject. 
 
 Sufficient knowledge and experience in the use of 
 explosives for this purpose have been accumulated. The 
 time has come when such a book can be prepared 
 authoritatively. 
 
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 These ditches show the result of cutting the sod and the earth along the sides before the blast- 
 ing. Shovel blades, axes and a hay-knife were used. A man cut a rod along one side in about two 
 minutes. The blast left the soil outside of the cut firm and intact, while scooping the contents of the 
 ditch out clean. (Upper, Miller Drainage District, Marion Co., Oregon; lower, Connecticut land of 
 Polytechnic Institute of Brooklyn.) 
 
The Matter of Farm Drainage 
 
 Much draining of agricultural land has been neglected because it has de- 
 manded so much money, time and hard work, and so many men. The 
 excessive cost of ditching has retarded plans to drain, and poor methods have 
 retarded actual construction. 
 
 In times past ditches have been made largely by hand shoveling. A few 
 of them have been plowed out when shallow ditches could be made to do the 
 work at all. But the digging of a few hundred yards of ditch 3 feet deep has 
 been a summer's work on a farm, and the draining of land always has been 
 very expensive and hard. 
 
 With the increase in the cost of labor, and the scarcity of farm help com- 
 pared to the numbers of men that used to be available, there is serious need 
 for means of draining that are easier, quicker and cheaper. Since ditching 
 with explosives has become well known and generally practiced, it has come 
 to be the desired method. 
 
 -V-t r>;^ 
 
 
 Observe the even spreading of excavated earth over the surrounding ground, leaving little elevated 
 ED bank on the edges of the ditch. Even in heavy, stiff clay such as this, the explosion grinds the earth 
 up pretty fine. (Chester Co., Pa.) 
 
 With few exceptions, ditches can be excavated with explosives anywhere. 
 The nub of the whole matter lies in the fact that one of the cheapest ways of 
 moving dirt known is with explosives. 
 
 To blast ditches practically all that is necessary is to punch lines of holes 
 and push charges to the bottom. The sides and bottoms of the blasted ditches 
 are not as smooth as if they were shoveled out, but they are even and true, 
 and the flow of water soon levels them down and smooths the bottoms. ; 
 
 The work can be done quickly, neatly and with no expensive outfit. It calls 
 for few men. A month's work by ordinary methods can be done in a day, or 
 a week's work in an hour. Ditches can be blasted through any kind of ground 
 except dry sand. The presence of brush, grass, stumps and stones is no bar to 
 this method of cutting out the ditches, though of course they dig out smoother 
 and cheaper when the nature of the ground is clean and clear. 
 
 As for size, ditches of almost any desired depth greater than 1 ^ feet and 
 any ordinary width greater than 33^ feet can be blasted out. Ditches in fields 
 
Representative blasted ditches in sandy loam of tlie Atlantic Coast section. In sucli material the 
 charges must be heavy and must be skillfully placed to produce the perfect results shown. With 
 proper care the excavation is satisfactory and the sides more even and true than in clay soils. ' 
 
 (Charleston, S. C.) 
 
and along roads, ponds, canals for drainage or boats, stream channels and 
 similar cuts for any purpose can be blasted out. 
 
 This book explains the possibilities of blasting and makes clear the 
 basis on which choice of a method for your work should rest. It shows how 
 to plan and to lay out drainage systems, and how to construct open ditches to 
 the best advantage. Other methods than blasting are recommended frankly 
 when conditions and purposes are such that can be used to the best advantage. 
 
 Conditions Demanding Drainage 
 
 Two classes of farm land should be drained. One is the usual swamp land 
 where the ground is saturated with water or at least is too wet for the growth 
 of cultivated plants. The other class is land now cultivated, but which at 
 some part of the year carries excess water. 
 
 The wet or damp lands may be merely low spots in fields, or may be entire 
 valleys. Low spots often can be dried by cutting a ditch through rims of higher 
 ground surrounding. If the wet condition is caused by overflow from streams, 
 the stream channels should be deepened or widened till they carry all the water. 
 If seepage from springs on the land or above it causes the trouble, a ditch cut 
 across the flow of the seepage water will be the proper remedy. If the water-table 
 is too high, a big open drain may gather and carry away the surplus, 
 lowering the surface of the ground water to where it will not interfere with 
 roots. 
 
 On account of the matter of moisture storage, as well as on account of 
 general fertility, all land which is cultivated should be drained thoroughly of 
 excess water. It is not enough to reduce the surplus to a point where meadow 
 grass will grow; the drainage must be sufficient to dry off the ground soon 
 after each rain and soon in the spring. 
 
 Roads always must be well drained if they are to remain solid and hold 
 their shape in wet weather. Crooked streams should be straightened, to pre- 
 vent cutting of the banks and overflowing, and ditches and streams too shallow 
 or small to carry the volume of water present should be deepened or widened. 
 Swamp conditions are a menace to health, breeding mosquitoes and their at- 
 tending diseases. It often pays to drain lowlands where water stagnates, from 
 the standpoint of health Eind comfort alone, when they are worthless for any 
 agricultural purpose. 
 
 The Value of Drainage 
 
 Good drainage not only removes surplus water but actually helps to store 
 moisture against dry weather. When soil is choked with water, deep rooting 
 of plants or trees is impossible, and the soil processes which make available the 
 plant food are hindered or altogether prevented. It is the absence of air al- 
 most as much as the presence of the water that does the damage. The better 
 land is drained to a proper depth in each case, the finer and more mellow and 
 crumbling it will be, and the more of useful moisture it will hold in the summer. 
 
 Swamp land usually is very fertile when the excess water is removed, and will 
 grow wonderful crops. It contains a rich supply of plant food. Such land 
 must be aerated — drained — and limed before its fertility can be used. 
 
 The direct loss of income from the idle acres in swamps can be figured by 
 anyone. But this is not the only loss. There is the decreased net profit from 
 other land that is farmed under the same ownership. The swamp land costs 
 interest on its purchase price and taxes every year. This cost must be paid 
 by the productive acres. 
 

 Two pictures that tell a story of swamp grass damming up a stream, which backs up and floods a 
 field, ruining the hay, or com or any other crop which may happen to be there. To dig out by hand 
 or plow out such a clogged stream-bed is difficult and expensive, but to blast it out is the work of one 
 man for an hour or so, at a comparatively small cost. (Mud Lick Farm, Julian, Center Co., Pa.) 
 
Kxssj^^ <t^ 
 
 
 Winding streams cut up and waste much land. They change their courses every year or so, tear 
 away the banks at the curves, gouge out deep holes and build up sand bars. They occupy many 
 times the area they would if straight, and practically ruin the soil which is worked over by the water. 
 (Mud Lick Farm, Julian, Center Co., Pa.) 
 
 There is another feature of the matter that ordinarily is overlooked. This 
 is the black eye which the farm is given by a ragged-looking piece of swamp 
 land touching the clean acres. Whether the farm is on the market or is to be 
 kept as a home, the waste lands cut down its value and damage its reputation 
 among all who see it, including the stranger passing by, the neighbors over the 
 fences and the man who lives on it. 
 
 It is a well-known fact that malaria disappears when mosquito bites are 
 eliminated, and that the mosquitoes can be eliminated by draining the swamps. 
 
 The excavation done by a single line of charges of explosive properly placed in watereoaked clay 
 soil is remarkable. The ditch resulting sometimes is two-thirds as deep as it is wide at the top. The 
 bottom is U-shaped. 
 
 8 
 
In the lowland sections of the country this has been done with great success. 
 Even in the flat lands joining the ocean where tide water sometimes washes in 
 over land and makes ponds, the opening out of channels has drained away the 
 water and killed off the mosquitoes. 
 
 Other enemies that breed and lurk in swamps are weeds and predatory 
 animals. The seed weeds in the swamps pollute all the surrounding land, and 
 the cleaning up of the swamp is a favor and a benefit to the entire neighborhood. 
 
 Horses and cattle often get mired into the soft mud and are unable to get 
 out without help. They may stick there and starve if not discovered and pulled 
 out, or they may break a leg, or sprain themselves in their struggles. 
 
 One of the meanest things a farmer has to do is to haul loads of hay, grain, 
 manure or fertilizer through a swampy place in the field. The remedy is to 
 open a ditch through the center, after which the soft ground will harden up 
 and the ditch can be bridged. 
 
 But not all wet land should be or can be drained. In general whether 
 it will pay to drain or not will depend on how cheaply the job can be done, 
 though this is such an indefinite rule that it is not of much value. Many a 
 drainage job that can be done for $50 to $75 will add $100 to $200 to the 
 value of a property. From a financial standpoint, a man is not justified in 
 spending more money than the crops that can be grown will return in a reason- 
 able number of years, though other considerations may make it wise to spend 
 
 The Essentials of Successful Ditching 
 
 It is well to have a clear idea of 
 ing to complete the plans for it. 
 
 The successful drainage ditch 
 should be straight, to give an even, 
 swift flow of water without cutting 
 out the banks or filling up the 
 bottom. Its sides and bottom 
 should be smooth and true, both to 
 facilitate the flow and for appear- 
 ance. It must be deep enough to 
 put the water-table at a proper 
 level. It must be wide enough to 
 give the capacity required by the 
 volume of water to be carried in 
 flood times. The grade, of course, 
 must be enough to carry the water 
 away and to make the drainage 
 action sure. 
 
 The excavated material ought 
 to be well scattered and spread 
 evenly over the surrounding land, 
 without leaving a ridge or dyke 
 along the sides of the ditch. When 
 this material is piled up along the 
 ditch it takes up ground space and 
 acts as a dam for surface water 
 and compacts the subsoil beneath 
 by its weight, making the drainage 
 of the fields much slower. ' Finally, 
 
 what to require of a ditch before attempt- 
 
 One of the best demonstrations of the value and 
 success of the blasting of ditches is in cutting a large 
 channel through difficult ground for a short distance, 
 as this picture shows. One man can do the work in 
 a couple of hours. The expense is not to be com- 
 pared to the cost of cutting the same ditch hy plow- 
 ing, hand shoveling or machine work. 
 
 (Valley Creek, Pa.) 
 
the ditch in respect to cost, time and men needed for construction, must come 
 within the available Umits. The cost must be low, the time of construction 
 short, the men required few, and the work not unreasonably hard. Frequently 
 if the ditching is to be done at all it must be by only two or three men in what 
 practically amounts to spare time. 
 
 
 The line of the ditch follows the line of the charges faithfully, making true curves and angles. It 
 should be the policy to eliminate all twists and to make the ditch as straight as a string whenever 
 possible. (Chester Co., Pa.) 
 
 There of course are many large agricultural, road, lumbering and other 
 enterprises to which these remarks do not apply, because the ditching must be 
 done and men are hired for the purpose. The managers of such propositions 
 are fortunate in having eliminated for them one of the chief difficulties of 
 farmers. 
 
 Ditches, canals and other such excavations not intended for drainage do 
 not differ much in requirements from drainage projects. Cost, time and labor 
 required always are the important considerations. 
 
 Nature of the Ground 
 
 The reasons why land is wet are few. There may be a layer of ground a 
 few inches or a few feet under the surface, holding the water from escaping 
 downward. The topsoil itself may be of such a nature as to prevent water from 
 percolating through it. The water may keep rising from springs, producing 
 the condition called seepage or spouty land. Again, the water-table, or height 
 of the surface of a nearby large stream or lake or bay, may be nearly up to 
 the surface of the ground, or the stream or ditch carrying away the water may 
 be too small or too high at its mouth. 
 
 The nature of the ground must be considered in deciding on the method 
 of ditching. Sand, for instance, is easiest to handle by some methods, and 
 hardest by others. Dry ground handles cheapest in some ways and most 
 expensively in others. In ditching you are likely to encounter hardpan, gravel 
 of all sizes, both loose and in solid beds, and every kind of mixture of these 
 materials. Each of these conditions calls for its own sort of treatment. 
 
 10 
 
, ti iiim. 
 
 A ditcli blasted through very dry ground without any side cutting. The result is not altogether 
 a success, since the excavation is reduced in amount and is incomplete, and the cost is high. The 
 soil is coarse sandy loam with much clay beneath. The blasting would have been much more suc- 
 cessful if the ground had been full of water and the sides of the ditch cut before the blasting was 
 done, (Near Snow Hill, Md.)- ■ 
 
 Heavy charging and skillful management will blast out a very good ditch through extremely dif- 
 ficult ground. Here the soil was matted with green roots. Some of them are left projecting into the 
 ditch, but most of them are broken off and thrown out. The excavation of earth was very complete, 
 owing to its watersoaked condition. (Georgia.) 
 
 M 
 
Choosing a Method of Draining 
 
 The methods that are available for making ditches are: 
 Shoveling by hand. 
 Plowing, 
 
 Trenching with machine equipped for excavating. 
 
 Blasting. 
 
 Each method has its place. In choosing a method many considerations 
 
 enter into a wise decision. The purpose for which the ditch is made — whether 
 
 open ditch or underdrain, canal for water or boats, and the like, must determine; 
 
 the character of the ditch. The kind of soil, the size of the ditch, the amount 
 
 Note the projecting knobs of earth held by matted roots of trees and brush. Such irregularities 
 in the sides of a ditch are not a disadvantage except in appearance in a ditch where the fiow of water 
 is heavy and swift. But when the volume of water is small and the fall slight the edges should be 
 smooth and straight. 
 
 and kind of obstructions, the time available before the job must be finished, the 
 men that can be put on the job, the capital available for labor and equipment, the 
 source of the water to be drained away, the height of the water-table, the use of 
 the land to be drained, the amount of water to be carried and the fall of the land 
 — all these factors have a bearing on the selection of the method of making a 
 ditch. 
 
 Tile Drains 
 
 No open ditch through cultivated land should be considered when 
 conditions are such as to make underdrains better, and when money is avail- 
 able for constructing them. 
 
 But in a great many places the nature of the ground or water flow is such 
 as to require open ditches. In other places they are just as good as closed 
 drains. For instance, through pasture land and woods an open ditch will do 
 just as well as an underdrain and better where there is a spring or brook 
 which overflows at times. In muck land closed drains are not practicable. 
 
 Ditches for immediate laying of tile cannot be blasted out with satisfaction; 
 the bottoms are left too soft to hold the pipe properly. If funds for tile drain-, 
 ing are not available immediately, an open ditch can be made by blasting 
 which, after a couple of years, will be entirely satisfactory for tiling, though 
 
 12 
 
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 Proper blasting will open a channel through thick brush and grass, though such a ditch will not 
 measure nearly so much in the clear as though the land was clean and free from roots. You can blast 
 channels for boats or for drainage through a marsh where the ground is under water. (Kentucky.^ 
 
 the earth required to refill the ditch will be scattered widely. Light blasting 
 very often is desirable, however, to loosen hard ground in order to make dig- 
 ging of tile ditches by other methods easier. 
 
 Open Ditches 
 
 Large ditches and canals, 1 5 feet wide or more, and miles in length, often 
 justify the use of a floating dredge. Those who are interested in methods of 
 trenching for underdrains, and in excavating machinery, floating dredges, 
 ditching plows and the like, should get Farmers' Bulletin 698 of the U. S. 
 Department of Agriculture. It goes into the subject in detail. 
 
 An entirely successful ditch blasted through heavy, thick muck. Note that the watertable is very 
 near the surface of the ground. The soil is not thin enough to cave in or float into the excavation, 
 hence the blasting is at its best. (In Howachitto Swamps, Adams Co., Miss.) 
 
 13 
 
When many stones, roots and 
 stumps are present, a dredge, or in 
 fact any excavating machinery, 
 cannot be used to advantage or at 
 all. Ditches less than 2 feet deep 
 can be plowed out cheaply, using 
 two or four horses hitched by means 
 of a chain to a plow of some kind. 
 Another injplement that is effec- 
 tive for making very shallow 
 ditches is a scraper, either with 
 or without wheels. A road machine 
 or scraper is about as good as any. 
 The trouble with them is that they 
 will work little more than to a 
 depth of a foot. They also are 
 expensive. Their advantages are 
 that they scrape the dirt well back 
 from the edge of the ditches and 
 make an even, clean-looking job by 
 machinery instead of by hand. 
 
 When tile is to be laid in hand- 
 dug trenches, begin the spade work 
 in the bottom of a plow furrow. 
 By running the plow twice in the 
 same place you can make the fur- 
 row nearly 1 2 inches deep. 
 Blasting of ditches is discussed under a separate heading. 
 
 Possibilities and Limits of Blasting 
 
 The blasting method can be used for making almost any open ditches 
 A blasted ditch made with one line of charges usually is about twice as wide 
 
 What can be done by blasting in sand. This big 
 ditch was made with explosives near Pinellas, Florida. 
 The conditions are about the most unfavorable under 
 which it is possible to blast out ditches. Heavy charg- 
 ing and electric firing were required here. 
 
 Blasting makes the cleanest and smoothest job in sandy loam that is saturated with water nearly 
 to the surface. Ifote how cleanly the edges of this ditch are cut. Also note that no excavated earth 
 was thrown to the right of the ditch, in the picture. A strong wind carried it all over to the left side. 
 
 14 
 
at the top as it is deep. The sides and bottom are fairly even. The dirt is 
 spread out widely without leaving ridges down the sides. Ditches can be 
 blasted successfully in clay, loams, gravel, thick muck, peat, and, in fact, every 
 sort of earth except very thin muck and dry sand. Ditches can be blasted 
 through sand when saturated with water. 
 
 It is easier to state the limitations of the blasting method than its possi- 
 bilities. As stated above, you cannot blast ditches through dry sand. Thin 
 muck runs into the excavated channels. In any ground where there are many 
 roots of trees or brush, the sides of the blasted ditch will be ragged unless the 
 roots are cut beforehand along the sides. In blasting through heavy sod, the 
 sod sometimes folds back without tearing loose, or else simply flops back down 
 into the ditch — unless the edges are cut before the blast. 
 
 These are the limitations of blasting, and there is a way to overcome each 
 of them except that of thin muck. The fact is that the way explosives will 
 cut out a narrow channel is really wonderful. Those who have not seen the 
 blasting of a ditch can have no idea of the efficiency of the work of explosives 
 for this purpose or of the clean and finished job they do. 
 
 Explosives work to the best advantage when the ground is wet — in fact 
 in thin mud. It takes less explosive to throw out a required sized ditch, or the 
 same amount of explosive will make a bigger ditch, when the ground is thoroughly 
 
 A big ditch blasted through a swamp where the mucls was abnost too thin. The sides of the 
 ditch moved in a little, but stopped as the water left them and they dried a little. Blasting is very 
 effective in muck, so long as the material is not so thin that it moves in and closes the excavation 
 later. (Gilliard's Lake outlet to Mississippi River, through Howachitto Swamp, Adams Co., Miss.) 
 
 wet than when it is only damp or is dry. The blasting may be done with per- 
 fect satisfaction through ground that is so soft that there is no footing for 
 horses and no support for wheels. In fact, it can be done when the surface 
 of the ground is under water. 
 
 Excessively soft ground, stones, stumps and roots are the things that 
 make ditching by hand or by machinery costly and difficult, if not impossible. 
 But they interfere with blasting very little and raise the cost only slightly. 
 Blasting of ditches can be done in dry ground of a heavy nature. The general 
 rule is that the wetter the soil, down to the thin muck stage, the better and 
 cheaper the blasted ditch. 
 
 15 
 
The cost of digging by hand in connection with plowing and scraping, in 
 any ditches more than 2 feet deep, is upwards of 25 cents per cubic yard, on a 
 basis of $1 .50 per day labor. The cost of blasting will range from 6 to 1 6 cents 
 per cubic yard, depending on the nature of the soil, its condition at the time 
 and the skill of the blaster. This comparison in itself is enough to demonstrate 
 the efficiency of the blasting method. 
 
 It is possible to blast out a good ditch through almost pure sand, as this ditch shows, provided the 
 ground is full of water and the operator understands his business well. 
 
 About the smallest ditch it is worth while to blast is 1 yi feet deep and 
 3^ feet wide. From this size up to 6 or 8 feet deep and 1 8 or more feet wide the 
 use of explosives has advantages over almost any other method under 
 favorable conditions. But in general the efficiency of the blasting method 
 falls off after the depth is greater than 6 feet and the width greater than 1 8 
 feet. For long ditches a floating dredge will be economical. Small ponds may 
 be dug by blasting. 
 
 In blasting ditches two or three men can do the work of a great many. 
 They can accomplish in a day or two what would take them months to do 
 by hand. 
 
 Laying Out the Ditch 
 
 The size or capacity of ditch required, the grades, the depth and the lines 
 should receive careful attention. When there is considerable length of ditch 
 or considerable acreage to be drained it is wise to employ a drainage engineer 
 or a professional surveyor in getting the grades and in determining capacity. 
 Except in very large operations the matter of depth and location of the lines 
 of drains is largely one for farmers themselves to decide, because they know 
 the requirements of the different soils and of farm operations, as well as 
 have had the chance of observing the flow of flood water. 
 
 The eye is not to be depended on in determining the fall of a piece of land 
 that is nearly flat. Use a level. One way of using it is to drive a post at the 
 upper side and fasten to this, by nailing or bolting, a crosspiece with a straight 
 edge up. Then lay a level on the straight edge and make it absolutely level. 
 The c?8SSpiece should point directly toward the lower side of the piece of land 
 
 16 
 
In big drainage projects where large canals must be made the blasting method often proves 
 economical. There is no doubt that explosives will do the excavating, as this picture shows. Labor 
 cost and compUcations are reduced to a minimum on account of the few men and short time required 
 for the blasting. 
 
 to be drained, where a helper must stand, holding a marker which he raises or 
 lowers on a pole. Sight over the straight edge and have him elevate the marker 
 till it is on a true level with your crosspiece. The difference between your dis- 
 tance down to normal ground surface or normal water surface, and his, will be 
 the fall.^_ 
 
 An "A" frame or any other support for the level will do if it will hold the 
 level steady. For about 60 cents, sights for attaching to the level can be bought 
 of almost any hardware store. Ask for Stanley level sights. They are as ac- 
 curate as rifle sights. Tripods for holding the level also are made by the Stanley 
 
 This ditch is a good instance of the speed and efficiency of the blasting of ditches. Three men 
 made it complete, as the picture shows — 1000 feet long — in S days. About 400 pounds of explosive 
 was used. Much cutting of roots and sod was required. (The Hart E. Hutchens Co., New Britain, 
 Conn.) 
 
firm and cost about $2.50 at most hardware stores. The plain level is not very 
 accurate. If you do not use sights, repeat the sighting two or three times to 
 make certain of the finding. 
 
 Another reliable way of getting a grade is to use water in a hose. Use a 
 length of 20 to 50 feet of hose. Turn up the ends for 6 or 8 inches and tie 
 them up. It is well to insert in these ends, tubes of glass, like the water-gauge 
 glass of steam engines. Fill the hose with water and lay it on the ground or 
 in bottom of ditch. ■ The height of water in the ends will show the level. You 
 can use this device round bends in a ditch. 
 
 A fall of one inch to each hundred feet is enough to carry off excess water 
 
 from a field 
 
 Grade, Fall and 
 Line of Ditch 
 
 m most cases. 
 This is for 
 straight 
 ditches. If the 
 ditch line is 
 to swing here and there, an inch 
 of fall is hardly a sufficient allow- 
 ance. 
 
 The appearance of grade is 
 deceiving. Few pieces of ground 
 are so flat they cannot be drained. 
 Watch the land when it is flooded 
 and the water is going down. Set 
 some stakes then to indicate its 
 level and its channels. If a small 
 stream flows through the land, the 
 line of sight should not follow its 
 wandering course. The total fall 
 should be determined from just two 
 positions — one where the stream 
 enters and one where it leaves. 
 
 The flow of the flood water is 
 a good guide in locating the proper 
 line for a ditch. This is the nat- 
 ural line of drainage. If nothing 
 else interferes, place the ditch in 
 this position. The idea is to have 
 it near as possible to a straight line and as short as possible. But avoid cutting 
 fields with open ditches when possible. 
 
 The one important factor to consider in determining how deep a ditch 
 should be is the proper height of the water-table in the ground. This is the 
 level of the water that will stand in a well or hole dug in the 
 wettest part of the field. The water should be at least 4 or 
 5 feet below the surface in ordinary heavy loam or clay, and 
 1 to 13^ feet in muck. 
 
 The deeper a ditch is the farther and more thoroughly it 
 will drain land. Your calculations as to how far you can rely 
 on one ditch to gather water and to effect the drainage of ground must be based 
 on this matter of the depth of the ditch. The nature of the ground has a good 
 deal to do with it, particularly with the rapidity of the drainage. A loose, 
 open gravel will drain out nicely in a few days, and a tight stiff clay will take 
 
 18 
 
 Part of a half mile of ditch blasted out com- 
 plete* with no work in preparation or finishing ground. 
 The ground was fuU of water, and transmitted deto- 
 nation was made use of to fire the charges in about 
 200-foot sections. Note that the line of the ditch is 
 truej the edges fairly even and smooth^ and the earth 
 well scattered. 
 
 Determining 
 Ditch Depth 
 
;^*afc-s^>-^' 
 
 The first shot (of 12 charges) of a ditching operation. Note particularly how abrupt and clean- 
 cut the end is. The last charge lifted its load fully and cleaned out the ditch in good shape. The 
 next one placed beyond will continue the excavation just as well. (Mud Lick Farm, Julian, Center 
 Co., Pa.) 
 
 weeks. Naturally the ditches should be closer together in the clay than in the 
 gravel. Other soils can be judged from these. 
 
 The depth must not be more than the water-level at the mouth of the 
 ditch or drain. This is a governing 
 factor in many places. When a 
 ditch empties in a stream you often 
 can carry the channel farther down 
 and secure a lower level if it is 
 needed; or the stream itself may 
 be deepened. 
 
 The water carrying capacity of 
 a ditch is most largely governed 
 
 by its width. 
 
 Often thenar- 
 
 rowest ditch 
 
 that can be 
 
 made will 
 
 have more 
 •capacity than is needed to carry all 
 the water there is. The bottom 
 should not be wide, but should be 
 narrow, almost like a broad V, 
 because the amount of water to be 
 carried at low water stage is small 
 and it should be confined closer to 
 make it flow better. In flood times 
 the water will rise higher and will 
 make a broader stream. 
 
 Where large swamps are to be 
 drained, or the flow from larger 
 
 Determining 
 Width of Ditch 
 
 This ditch is 5 feet wide and 3 feet deep. It 
 was blasted out with one row of charges placed 18 
 inches apart, each charge consisting of one stick of 
 powder. About 100 feet of the ditch was excavated 
 at each explosion. 
 
 springs is to be carried away, a ditch of minimum width sometimes is not big 
 
 19 
 
enough. If you can calculate the volume of water to be carried away, you 
 then can figure the correct width for your ditch. Measure the flow per minute 
 in cubic feet at some outlet. Or measure the amount of standing water by 
 getting its depth and extent. Provide ditch enough to pass the volume 
 present in the required time. In any case the ditch should be big enough to 
 clear away the water of a 2 or 3 days' rain shortly aiter it stops coming down, 
 and to take care of spring floods. 
 
 How to Make Ditches by Blasting 
 
 Ditches are blasted by loading 
 suitable charges in holes made in a 
 roworline. Each 
 charge of explo- 
 Description of sive properly 
 Blasted Ditch placed for ditch 
 blasting will 
 blow out, rough- 
 ly stated, a crater which is half to 
 three-quarters as deep as it is wide. 
 Nearly all the dirt is thrown out. 
 Most of it is lifted to a height of 
 about 200 feet in the air, requiring 
 some seconds before it returns to 
 the ground. 
 
 The sides and bottom of 
 blasted ditches have 6 to 1 2 inches 
 of loose dirt, which can be left 
 where it is if the ditch is big enough 
 in the clear, or can be taken out 
 easily and cheaply by shoveling or 
 
 In these ditches the excavation of earth was satisfactory, but the number of roots was so great 
 that the result as a whole is not what it should be. No side-cutting was done before blasting. If 
 there had been, the resulting ditch would have been smooth, straight and deep. In blasting through 
 brush and timber, the long, sharp shovel blade, the hay-knife and the axe are necessary tools. 
 (S. Chester Coursey, Hayden, Md.) 
 
 20 
 
with light horse scrapers if a larger ditch is wanted. Good blasting practice 
 will so load the charges that the ditch as cleaned out by the blast will be big 
 enough in the clear and will require very little, if any, hand finishing. 
 
 Firing Charges 
 
 One of the first things that must be considered when planning to make a 
 ditch by blasting is the method of firing the charges of explosive. Most of the 
 rest of the operation hinges on the firing so much that this matter must be de- 
 termined before even buying the explosive. 
 
 The standard practice is to fire all charges electrically, as will be described 
 immediately following. This method is sure in results under any conditions. 
 Ordinary cap-and-fuse firing cannot be used successfully in ditching, except by 
 the transmitted detonation method in which the center charge only is set off 
 by a cap, the rest being fired by shock transmitted through the ground. This 
 method is fully explained on pages 22 to 25. 
 
 General Method of Firing 
 
 Ditches can be blasted through any sort of ground except dry sand when 
 the charges are fired in this way. The procedure is as follows: 
 
 The charges are prepared for loading, with electric blasting caps, in the 
 manner described on pages 34 to 38. Prime each charge. Holes are made in 
 the ground on the ditch line and the charges are loaded as described in follow- 
 ing pages. 
 
 Typical loading of ditch blast for straight electrical firing of all charges for 33^' x 7' ditch. 
 
 The holes or charges should be spaced 30 to 40 inches, and where very 
 heavy charges are used, as much as 50 or 60 inches apart. They must 
 be close enough together so that all the earth between each two will be thrown 
 out clean, leaving no ridges in the bottom of ditch. Thirty inches ought to be 
 close enough under any conditions of soil and size of charge. The only way of 
 determining definitely just how far apart the charges should be is to make test 
 shots, as suggested on page 31, in the discussion of amount of explosive required 
 for charges. As many charges should be loaded as your electric current can 
 fire. 
 
 The actual firing is done by connecting the wires of all the charges and send- 
 ing an electric current through them. An electric blasting machine should be used 
 to supply current, though power or light current can be used. A full discussion 
 of the details of how to connect wires and to fire, is contained in the special 
 chapter on the subject in the latter part of this bulletin. 
 
 You can fire as many charges as your blasting machine will handle. The 
 machines are made in different sizes, to fire 3 to 1 50 charges at once. Procure 
 a large machine if you have miles of ditch to blast, but if you have only a few 
 hundred yards, a 30-charge machine is big enough. 
 
 21. 
 
The proper explosive for blasting ditches by this method depends 
 somewhat on the soil. In all clay and heavy soils use 20% ammonia powder 
 or dynamite, and for large ditches use 30% or 40% ammonia powder or dyna- 
 niite except when the work is under water. (See page 46.) In blasting ditches 
 m wet sand or other light ground use 50% nitroglycerin dynamite or powder. 
 Where charges must remain under water more than half an hour, use nitro- 
 glycerin explosives only, for ammonia explosives will deteriorate if soaked for 
 excessive periods of time. It is well to use a low-freezing grade of the explo- 
 sive at any time of the year, since this guards against incidental chilling, and 
 since the cap is strong enough to detonate all grades fully. 
 
 Electric blasting caps, connecting wire, leading wire and blasting machine 
 with the other tools needed for loading, are the supplies demanded for ditch 
 blasting by this method. ^ 
 
 Depth for holes, amount of explosive per charge and many other details 
 of the loading are discussed on pages 28 and 30. 
 
 Transmitted Firing 
 
 When the ditch is to be blasted through ground that is saturated with 
 water, the method of transmitted firing often can be used to advantage. In 
 order to insure its complete and unquestioned success, the water must cover 
 the charges and had better rise in the holes nearly to the surface of the ground. 
 
 Under such conditions transmitted detonation can be expected to succeed 
 even in sandy ground and gravel. It is in muck and clay fully saturated with 
 water that the method is most successful. 
 
 Showing typical loading of transmitted detonation ditch blast — ^fuse firing— for 3H' 2 7' ditch. 
 
 Transmitted firing is made possible by the fact that high explosives can 
 be fired by shock (as by that given by a cap, for instance). Under the conditions 
 of soil described above and of proper loading, the shock of the explosion of one 
 charge will travel through the ground and water with enough force to fire the 
 next charge, and so on down the line. So rapidly does this take place that in 
 a line of charges himdreds of feet long you cannot see any difference in time 
 between the middle and end explosions. 
 
 If sticks of explosive are laid on a plank a foot apart and one of them is 
 fired with a cap and fuse or otherwise, the others likely will be exploded by the 
 influence projected through the air. In actual ditching work the shock of one 
 
 22 
 
charge cannot be depended on to travel through the ground strongly enough 
 to bring about full and complete detonation more than a couple of feet. 
 
 The usual distance apart that is best for charges to be fired by transmitted . 
 detonation is 1 5 to 20 inches. The exact distance in any particular soil at any 
 time must be determined by test shots. Try a shot of 8 or 10 charges (of the 
 amount of powder and at the depth of loading required, as explained on pages 
 30 and 31), spaced 12, 15, 18, 20, 22, and 26 inches apart. 
 
 Careful observation of the blast resulting will show the point beyond which 
 charges fail to explode or explode weakly. The cor- 
 rect spacing of charges, to insure full detonation, will 
 Spacing of Charges be about two-thirds of this limit. 
 
 One charge may fire another at a greater dis- 
 tance than is economical, because it merely may ex- 
 plode it weakly, without developing anything like the full force and speed. 
 And on top of that, each weaker explosion sends a still weaker one on to the 
 next charge, till a point is reached a few charges away where the shock trans- 
 mitted is not enough to bring about firing at all. 
 
 This weakening of the transmitted shock is important, because the strength 
 of an explosion of powder or dynamite depends on the severity of the shock 
 which fires it. For illustration, and not that these figures bear any relation to 
 the true amount of force, if the first charge, the one fired with a cap, gives 
 off 1 pounds of energy in the form of a shock, and this 1 pounds is diminished 
 to 8 pounds by the time it reaches the next charge, this second charge will 
 not detonate with quite 10 pounds of shock energy. It may have only 9 or 8. 
 And in turn, the shock energy from it will be diminished to 6 or 7 on reaching 
 the third charge. If the particular kind of explosive used requires a full 6 pounds 
 of shock to detonate it completely, the transmitted method of firing is going to 
 fail. Even of those charges which do explode, half will give much less than 
 their full force. 
 
 Water is not elastic, but air is, and dry soil is eind absorbs shock because 
 it contains a good deal of air. The gases of an explosion drive water-soaked 
 
 When roots and sod are not cut along the sides of the ditch hefore the blasting, the edges are 
 never as smooth and as straight as with cutting. An effort was made to trim this ditch up after the 
 blast. It carries water about as well, but it doesn't look to be as good. (In Iililler Drainage District, 
 Marion Co., Oregon.) 
 
 23 
 
ground as a steel rod can be driven by a hammer. In it there is but little 
 give," hence the shock travels with a minimum of loss in force. In dry 
 ground the air cushions the blow of the gases and eases them to a standstill 
 within a short distance. Clay is more solid than sand, which fact explains 
 why transmitted detonation works better in heavy soils than in light ones. 
 
 The nature of the ground and the amount of water present therefore 
 largely govern the spacing of charges, though a large charge of course will throw 
 a shock slightly farther than a small one. 
 
 As will be seen from foregoing named facts, the effects of lack of water 
 and of light, spongy or sandy ground, can be counteracted somewhat by set- 
 ting charges closer together. When necessary it is practicable to put them 
 only a foot apart. To put them closer, however, is not practicable, for it costs 
 too much. On the other hand, when the charges are heavier than ordinary — 
 say of two sticks or more — in wet, heavy ground, they may be spaced up to 
 26 inches apart with satisfaction. 
 
 Temperature influences transmitted detonation only by reason of the fact 
 that explosives are less sensitive to shock, and harder to fire when cold than 
 when warm. All grades explode easiest when at a tempera- 
 ture of 70 to 80 degrees. Straight nitroglycerin powder or 
 Temperature dynamite must be used at a temperature of higher than 50 
 of Ground degrees. It is not well, for many reasons, to attempt to fire 
 
 too many charges at once. Several hundred can be fired suc- 
 cessfully sometimes, but the usual limit had better be 50 to 1 00. 
 
 When the nature of the ground, amount of water present or temperature are 
 not of the best for securing transmitted detonation, sometimes matters may be 
 helped by taking advantage of the fact that blasting caps are much more sen- 
 sitive to shock than the explosive itself. Place a common blasting cap, without 
 a fuse, but with the open end filled with tallow, every 25 to 50 feet. These 
 caps may help to restore the diminished force of explosion, making satisfactory 
 detonation extend much farther than it would without them. 
 
 A ditch 10 feet wide and S feet deep tlirough newly cleared land. The extra width of the exca- 
 TatioQ helped to tear entirely loose and throw out stumps and roots, leaving the edges comparatively 
 clean of projecting roots. Under such conditions finisliing the ditch after blasting is better than to 
 try to cut the edges before. (Paragould, Ark.) 
 
 24 
 
Stones, roots and old logs interfere with transmitted detonation. When 
 these are located in the line of the ditch it is necessary to lire charges on both 
 sides of them as at the beginning. Pay careful attention to changes in soil as 
 you work along the ditch line. It may be necessary to shorten the spacing, 
 or, again, it may be possible to lengthen it and save money. 
 
 The firing of the line of charges by the transmitted detonation method is 
 
 done by loading the required number of charges without priming or with caps 
 
 and no fuse as described above, all except the center charge 
 
 Prime Center of the row. In it place a double charge of explosive, or at 
 
 Charge least an extra stick of explosive, primed with cap and fuse or 
 
 with electric blasting cap. Fire this charge in the usual way. 
 
 Sometimes an electric blasting cap placed at each end as well as at the 
 
 middle of the line will fire difficult charges successfully. Once in a while the 
 
 electric blasting caps may be needed even closer — say every 3 to 5 charges. 
 
 The proper explosive for transmitted firing ditch blast- 
 The Explosive ing is nitroglycerin dynamite or powder of 50% strength 
 to Use — either regular or low-freezing. The 20% strength dyna- 
 
 mites and powders recommended for electrical firing cannot 
 be used at all under this method, because they are not sensitive enough. 
 
 Summary of Firing Facts 
 
 Transmitted firing requires only the explosive itself, and a cap and some 
 fuse for each couple of hundred feet of ditch, while electrical firing. requires 
 wiring, an electric blasting cap for each charge and a blasting machine or other 
 source of current. This advantage of the former method very often is offset, 
 however, by the fact that it requires nearly twice as many holes as electric 
 firing. It is easier to load two sticks in one hole than to make two holes. In 
 addition, electric firing always can be depended on for the desired results, while 
 transmitted firing will succeed only when the ground is full of water. As for 
 quantity of explosive required by each method to excavate any certain ditch 
 where either can be used: In theory the two methods require about the same. 
 In practice, however, more will be used in transmitted firing, unless the work is 
 done very skillfully. The saving in the use of this method comes largely from 
 a saving of electric blasting caps and time, and the need for little e'quipment. 
 
 Preparation of Ground and Loading 
 
 During the early days of ditch blasting, before experiments had standard- 
 ized practices, much objection was taken to the ragged edges of ditches blasted 
 4 through sod and through brush and woods. The sod would 
 
 not tear loose and fly away from the ditch. It would either 
 Cutting Roots fold back and make a ridge along the ditch, or it would flop 
 and Sod back into the ditch after the dirt beneath had blown out. 
 
 The remedy is to cut the sod and roots along the edges of 
 ditch before blasting. 
 When there is sod, two furrows should be plowed along the ditch line — 
 one at each edge. Another plan is to cut along the sides of the ditch-to-be with 
 a spade, axe or hay knife. In case the line of the ditch runs past trees, or 
 through brush or forest land, the roots should be cut on both sides the ditch. 
 An axe is needed for the big roots. Where there are many roots the ground 
 should be cut 18 inches deep. 
 
 Make the cut at the angle the side of the ditch should have, say about 45 
 degrees. The blast will clean out the dirt to the cuts and will leave the wall 
 on the outside firm and intact. Cutting the edges of the ditch saves trouble 
 
 25 
 
and work after blasting. It insures that the sides and edges of the ditch will 
 be as straight as though the ditch was shoveled by hand or plowed. But it 
 
 should not be understood that 
 ditches cannot be blasted without 
 cutting the ground. Except through 
 extremely heavy sod and roots, 
 explosives used alone will clean out 
 good channels when loading and 
 firing are done properly. The cut- 
 ting of the edges simply makes a 
 smoother, more complete job. 
 
 The charges should be placed 
 along the center line of the pro- 
 posed ditch, except where the 
 ground is harder, 
 or higher at one 
 Locating Line side than at the 
 For Holes other, when they 
 
 should be placed 
 6 to 12 inches 
 from the center toward that side. 
 The eye is not capable of keeping 
 the line of charges true. Stretch a 
 string where they should go. In 
 making the holes the man should 
 have a measuring stick to space 
 them accurately. Guesswork on 
 this point is likely to be expensive. 
 Make the holes straight down 
 into the ground. The practice 
 used to be to make them at a 45 
 degrees slant, but this offers no advantage in any way. 
 
 It is much easier to make holes in soggy ground than in dry ground. In 
 fact, it is almost impossible to sledge down a bar in some dry ground. When 
 there are no stones, a soil auger often is of advantage, though the bar and sledge 
 are hard to beat for speed and results. The only modification of the up-and- 
 down position of the sticks or charges that is desirable is when you are deepen- 
 
 A typical instance of wliat results from an attempt 
 to blast a ditch through heavy sod without first cutting 
 the sides. The sod breaks loose in the middle of the 
 ditch and either folds back without tearing loose or 
 falls back into the ditch after the dirt beneath it has 
 been swept away. Such ground should be thoroughly 
 watersoaked and the edges of the ditch cut with 
 shovels or hay-knife, or at least by plowing furrows. 
 (Virginia.) 
 
 ^^ . ^"-r*-^ - 
 
 
 \ J 
 
 MUD ; 
 
 
 
 
 _^ 
 
 
 
 ( ^^^. 
 
 -/5 
 
 
 i^^^A 
 
 " 
 
 
 
 
 
 WATER ^ 
 
 
 
 
 
 / 
 
 \ 
 
 Typical loading for deepening ditch with bottom of mud — electrical firing of center charge for 
 
 transmitted detonation. 
 
 ing ditches already made, with bottoms of thin mud or thick muck. In such 
 material you need punch no holes. Just push the sticks into place down in 
 the mud with your hand and place them in a horizontal position lengthways 
 of the ditch. 
 
 26 
 
Preventing Dirt 
 Falling into Ditch 
 
 If you have a windy day for 
 
 the blasting, with the air drawing 
 
 strongly across the Hne of the 
 ditch, you 
 will be sur- 
 prised to see 
 how far the 
 falling dirt 
 will be car- 
 ried away from the ditch during 
 
 the few seconds it is in the air. On 
 
 a quiet day, 6 to 1 2 inches of dirt 
 
 will fall back into the ditch. On 
 
 a windy day your finished ditch 
 
 will be several inches deeper and 
 
 wider than on a calm day. Do not 
 
 take from this that a windy day is 
 
 demanded for satisfactory results. 
 
 The force of the blast spreads and 
 
 scatters all but a little of the dirt. 
 
 The wind merely helps. 
 
 When water covers the charges, 
 
 be sure to make the primed sticks, 
 
 and the cap and fuse, waterproof 
 
 with tallow or paraffine at points 
 
 where they join. Shoemaker's wax 
 
 is Another good thing, but is ex- 
 pensive. Tar and thin lubricating grease are very poor 
 materials for waterproofing. 
 
 Waterproofing When water covers the charges you should arrange to 
 
 Charges load them and to fire them quickly. A good plan is to make 
 
 all the holes for one section, then prepare the charges, as to 
 priming and waterproofing and distributing them along the 
 line. Quickly test each hole for fallen stones, caved-in dirt, and push the 
 charges to the bottoms of the holes. It is best to limit their soaking to a 
 half hour. The explosive is likely to weaken if left too long. 
 
 If the holes cave in soon after the bar is withdrawn, do not attempt to 
 load and blast long sections at a time. In loose gravel and sand, especially 
 where water cover the surface or nearly so, you will have trouble getting the 
 charges down to the bottoms of holes. The best plan is to get a tin tube 
 about I ^2 inches in diameter and sink it in the hole over the bar. The 
 explosive then can be loaded without trouble when the bar is withdrawn. 
 
 Generally speaking, a ditch charge should be tamped slightly. The more 
 tamping you use the broader your ditch will be in propor- 
 tion to its depth. If you want a narrow ditch you must 
 Tamping Ditch let the gases rip their way upward easily. In dry or damp 
 Charges ground, fill the hole about half full and tamp well. When 
 
 water rises high in the hole, use no tamping at all, except 
 to tramp shut the upper 6 inches. 
 The ground had better be warm for ditch blasting. If it is cold you must 
 load and fire the charges quickly, to prevent chilling of the explosive. A light 
 
 An explosion throws the earth so high that the 
 slight additional depth or height of sides met with in 
 deepening a ditch does not interfere materially with 
 the excavating action of the blast. Probably a little 
 dirt is caught and rolled back by the side walls, but 
 the percentage of the total lifted is small. 
 
 27 
 
crust of frozen ground makes little difference when charges are handled 
 properly; more than M to 3^ inch will interfere seriously. 
 
 Regulating Depth and Width 
 
 The dirt will clean out 6 to 8 inches deeper than the bottom end of the 
 charges when conditions are normal. Explosives work more efficiently in ditch 
 
 blasting when they are placed as shallow as possible. 
 
 When the holes are too deep an excessive amount of 
 Depth for Charges explosive is required. A layer of hardpan or cemented 
 
 gravel in the ground to be removed requires slightly 
 
 deeper placing than soft ground. The rule for the 
 usual job is to place the charges within 6 inches of the bottom depth desired, 
 and for large ditches and heavy charges within 10 or 12 inches of the desired 
 depth. The exact depth may be ascertained by trial shots. 
 
 The greatest depth it is practicable to blast at one shot is about 6 feet. 
 If a deeper ditch is wanted, blast a second time in the bottom of the first ex- 
 cavation. (See table on page 31 for depths for charges.) The blasting out of 
 very large canals should proceed along these lines. They involve no principles 
 not explained for the making of small ditches. 
 
 A chaimel 35 feet wide and 6 feet deep that was excavated by blasting. The water has smoothed 
 the sides a little, but in the main the big ditch looks in the picture as it looked after the blast which 
 opened it. The cost of such ditching can be figured accurately in advance when dimensions are known, 
 the kind of soil and its condition considered, and the cost of explosions at hand. (Athens, Ga.) 
 
 One line or row of charges frequently will make a ditch up to 12 feet wide 
 and 6 feet deep. To make wider ditches use 2 or more rows. 
 
 Usually 2 rows of charges will be needed for ditches between 8 and 1 2 feet 
 wide if less than 4 to 6 feet deep, and 3 rows for ditches 12 
 to 1 8 feet wide. 
 Wide Ditches The lines or rows of charges should be placed about 4 
 
 feet apart, except where the charges consist of more than 4 
 sticks and are close together in the rows on account of 
 transmitted detonation, when the rows may be as much as 6 feet apart. In 
 blasting out very wide and shallow ditches or canals, it sometimes is of ad- 
 vantage to load 2 rows with light charges rather than to attempt to blast out 
 
 28 
 
Half stick loading for very small ditch. 
 
 Single-row loading for large ditch — if larger ones are 
 
 needed, more rows of charges. 
 29 
 
the ditch to the required width with one row heavily loaded. The heavy 
 charges might dig deeper than required. (See table on page 31). 
 
 Invariably all the rows should be fired together. This, of course, is ac- 
 complished when the electric method of firing is used. When using the trans- 
 ' mitted detonation method, put in extra charges between the rows at the center 
 charges, and then fire one — usually the center charge of the middle row — with 
 a cap and fuse. All these center charges and extra charges should be heavier 
 than usual. Put in an extra stick, at least. A still better way with transmitted 
 detonation is to fire the center charges of all the rows together electrically. 
 
 
 A pond excavated entirely by blasting. Several rows of charges were loaded and fired simul- 
 taneously. The wind carried the earth to one side, forcing it to fall on adjoining ground instead of 
 back into the hole blown out. (H. £. Ellis, Ashland, N. J.) 
 
 Amount of Explosive Required 
 
 Before giving tables of the average amount of explosive required for vari- 
 ous sized ditches, it is well to describe a few typical examples of ditches that 
 have been blasted, of which records were kept. 
 
 In a clay soil, with water rising almost to the surface of the ground in the 
 
 holes punched for charges, charges of one stick of straight 
 
 nitroglycerin explosive placed 18 inches apart and 30 inches 
 
 Examples deep blew out a ditch 4 feet deep. 3 feet wide at the bottom 
 
 and 7 feet wide at the top. 
 
 In a similar soil, with less gravel, charges of one-half stick 
 of straight nitroglycerin explosive placed 1 5 inches apart and 1 8 
 inches deep made a ditch 2)^ feet deep and 5 feet wide. At another point in 
 the same field, on the same day, charges of 2 sticks (one pound of same ex- 
 plosive), placed 30 inches deep and 24 inches apart, made a ditch 9 feet wide 
 and 4 feet deep. 
 
 In loam ground, too dry for successful transmitted detonation but still 
 somewhat damp, charges of 2}>4 sticks placed 2}/i feet deep and 3 feet apart, 
 and fired electrically, cut a ditch 4 feet deep, 8 feet wide at the top and 2 feet 
 wide at the bottom. 
 
 Through a thicket with brush and small trees measuring 1 to 3 inches in 
 diameter, in heavy pure loam well soaked with water, charges of 2 sticks of 
 
 30 
 
straight nitroglycerin dynamite placed 22 inches apart and 3 to 33^ feet deep 
 made a ditch 4 feet wide at the bottom. The ditch was loaded too heavy. 
 Charges of IJ/^ sticks would have been better. 
 
 In very wet and miry clay, a ditch 20 feet wide at the top, 1 2 feet wide at 
 the bottom and 6 feet deep was blasted with 3 rows of charges of straight nitro- 
 glycerin explosive. All the charges were spaced 20 inches apart in the rows. 
 The charges in the middle row were 13^ to IJ^ sticks, varying a little on ac- 
 count of variations in the soil along the ditch. In the two outside rows the 
 charges were one stick each. The rows were placed 4 feet apart. One section 
 of the same ditch was cut out to a depth of nearly 8 feet by using 1 J^ sticks to 
 the charge in the 2 outside rows, and 3 sticks to the charge in the middle row. 
 
 When the ground is fairly heavy and is full of water you can count on each 
 
 pound of explosive properly placed to clean out 1 ^ to 2 cubic yards of earth. 
 
 The variations from this rule, both ways, will be on 
 
 account of the presence or absence of water, the nature 
 
 Amount Excavated of the soil and the size of the ditch. A ditch made 
 
 By One Pound of with a single line of charges (measuring, usually. 
 
 Explosives 3 to 4 feet deep by 3 feet wide at bottom and 6 to 7 
 
 feet wide at top), will give the highest efficiency, 
 
 and when the conditions are very favorable will show 
 
 even a little more than 2 cubic yards per pound of explosive used. 
 
 As the amount of excavation in one body increases, the efficiency of each 
 pound of explosive will fall off somewhat. In very large ditches that are wet 
 you will get out only IJ^ cubic yards per pound of powder. In dry ground 
 blasting, particularly if the ground is light, IJ^ or even one cubic yard per 
 pound will be the average. 
 
 Number of Half-Pound Sticks of Explosive Required per Charge for 
 
 
 Blasting Ditches 
 
 
 Depth 
 
 Depth 
 
 Amount Charge 
 
 Amount Charge 
 
 Ditch 
 
 Hole 
 
 Transmitted Detonation 
 
 Electric Firing 
 
 2 ft. 
 
 l^ft. 
 
 % Stick 
 
 ^ Stick 
 
 ly^h. 
 
 2 ft. 
 
 ^ stick 
 
 1 Stick 
 
 3 ft. 
 
 2Hft. 
 
 1 stick 
 
 13^ sticks 
 
 4 ft. 
 
 3Mft. 
 
 13^ sticks 
 
 23^ sticks 
 
 5 ft. 
 
 4Mft. 
 
 2 sticks 
 
 33/^ sticks 
 
 6 ft. 
 
 5 ft. 
 
 23^^ sticks 
 
 5 sticks 
 
 The width of the ditch can be calculated by doubling the figure for the 
 depth in case of a single row of charges, or in the case of more than one row, 
 by adding to the figure for double the depth the distance between the rows 
 of charges. 
 
 The table given above is correct for average conditions. Since variations in 
 soils, temperature and other factors make necessary varying loading, the 
 figures here should be used as a guide for starting test shots. 
 
 No ditches should be blasted without testing the loading thoroughly be- 
 fore proceeding with much work. Blast small sections at a time, and vary the 
 loading to suit the changes in the nature and condition of 
 the ground you encounter along the ditch line. Clay, sand. 
 Making muck, loam and gravel all require variations in depth of 
 
 Test Loadings charge, amount of explosive and sometimes in spacing of 
 charges. Proper tests will enable you to decrease the cost 
 and to make a better ditch than otherwise would be possible. 
 
 31 
 

 7 T 
 
 Typical test loading to determine proper charges and placing of explosives for electrical filing. Note 
 the variations in spacing between holes as well as in amount of explosives used. (See page 23.) 
 
 Five to ten holes mcike a good test. This should be repeated several 
 
 times. Vary the depth and spacing and the amount of charges. Remember 
 
 that proper blasting will make perfect ditches at low cost, and that the only 
 
 final way of determining proper loading is to try it. Well-balanced charges 
 
 will be so loaded and spaced that the gases will lift the full load of dirt without 
 
 overlapping much and without skipping any ground between. Load just heavy 
 
 enough to insure clean excavation without excessively high throwing of dirt. 
 
 Making 3-foot holes in clay and gravel, preparing charges, loading and 
 
 firing can be done by one man at the rate of 20 to 50 charges per hour. If 
 
 there are meiny stones in the ground, or if the ground is 
 
 hard, the work will go slower. Wet gravel makes slow 
 
 Time Required work. Two or more men will get more done in proportion 
 
 than one man. Under favorable conditions one man has 
 
 blasted out 1,000 feet of ditch 3 feet deep in 12 hours. 
 
 One man should be able to blast 350 to 450 feet of ditch per day through 
 
 brushy ground; if the land is clean he can do more, though where ground is so 
 
 dry as to cause trouble in making holes, the work will go slowly. 
 
 4. 
 
 I . •-^^,^-v^'^ 
 
 ^adl ffl"* *■ *^ 
 
 j:;^^ 
 
 A crew of ten men — eight laborers, one blaster and a boss — working at a big ditch. The em- 
 ployment of so many men is not justified except for very long ditches, for the job lasts only^ a day or 
 two. A good sized crew enables the blaster to place and to fire the charges quickly, which is an 
 advanteK*' when the holes fill with water and when the temperature is low. (Max Ostner, Diehl- 
 stadt. Mo.) 
 
 32 
 
\*-r/fm'AO£0 i , 
 
 V. 
 
 £Xre/i-3/OAf BA/f 
 
 Ditch blasters should have a soil auger, 
 two crowbars, a sledge, a couple of long- 
 handled shovels and a cutting spade. One of 
 the bars should be 4 or 5 feet long and should 
 be constructed for driv- 
 ing. The other should be 
 Tools Required 6 or 7 feet long, and may 
 be made of piping, with 
 a solid sharp steel point 
 welded in. It is for use as a churn drill, with- 
 out sledging. A broomstick or a wooden rod 
 about XYi inches in diameter, for pushing the 
 charges down and tamping, and an axe to 
 help cut roots, also are handy. Of course, 
 boxes or baskets for carrying explosives, cap 
 crimpers and the usual outfit for handling and 
 loading explosives as described on pages 36 
 and 37, will be required. 
 
 ^U/^CH BJUJ 
 
 How to use pi|)e io make a punch bar 
 or to extend an auger. 
 
 Incid&ntals 
 Large stumps, stones or other obstructions 
 along in the line of the ditch require a little 
 extra explosive. Stumps up to 6 inches through and boulders up to 18 
 inches in diameter will be thrown out by the regular ditch charges 
 
 steel bar for making 
 holes. 
 
 Soil auger — note 
 long point. 
 
 ii#####^«^ 
 
 Above these sizes use extra loading, as follows: For each 6 inches of the diam- 
 eter, use one stick of explosive. For stumps larger than 30 inches, use 3 to 4 
 
 A good kind of crimper. 
 
 Sticks for each foot of diameter. Put the extra explosive directly under the 
 stump or stone. 
 
 How to place charges under obstructions in the ditch line. 
 33 
 
Through heavy sod, as shown here, blasting cuts the sides somewliat irregularly unless the 
 grass roots are first sliced with a shovel blade or hay-knife. This ditch is well opened and entirely 
 successful, but a good many projecting chunks of sod are left sticking from the sides. 
 
 Ditches blasted through ground that has a raw surface and no roots will 
 
 require no finishing afterwards. The edges and sides should be fairly true and 
 even and the dirt should be well scattered. There will be 
 few or no ridges along the ditch. Even through sodded 
 
 Finishing Ditch ground and through woods and brush, when the sides of 
 the ditch have been cut before blasting, there will be little 
 hand work needed. If no preparatory cutting is done, 
 
 however, some shoveling to smooth the sides and some cutting to take out 
 
 projecting roots and sod may be advisable. 
 
 
 This ditch was blasted out on a still day, and most of the dirt fell straight back to the ground. 
 But it was spread out so that only a little of it fell in the ditch. The few roots projecting into the 
 excavation can be cut off with little trouble. It is the roots of sod and matted roots of smaller brush 
 and trees which give the trouble in blasting and require cutting beforehand. (Robert Jemison, Bif- 
 mingbam, Ala.) 
 
 34 
 
This work should be done right after the blast, before the water has a 
 chance to compact the sides. If necessary, leave dams of unblasted sections 
 3 or 4 feet long every few hundred feet in the ditch, to hold back the water 
 long enough for finishing. They can be blasted out afterwards. An old axe 
 or a sharp grubbing hoe or adz will cut the ends of roots easily. But all this 
 work can be avoided and a better ditch result if you will do the cutting before 
 the blasting. Large clods, pieces of stumps or roots and stones in the ditch 
 channel after blasting should be thrown out without delay. 
 
 It has been stated (page 12) that ditches for tile or pipe cannot be blasted 
 out satisfactorily. The dirt can be loosened with light charges, however, and 
 the shoveling or excavating by other means thereby made much easier. If th^ 
 pipe is to be placed deeper than 4 feet, it even is practicable to blast a 3-foot 
 or deeper ditch on top, leaving only a little more excavating to do in the 
 bottom. One must bear in mind, however, that the blasting throws dirt too 
 far away to be shoveled in to cover piping. Loosening as explained above, 
 however, to make digging easier, does not throw the dirt away. 
 
 Two post electric blasting machine- 
 push down type. 
 
 35 
 
Preparing Charges of Explosives for Firing 
 
 A charge of explosives for the purposes of these directions is considered to 
 be all the explosives needed for a single hole with cap and fuse or electric 
 blasting cap properly inserted in the stick of dynamite or 
 powder (see pages 37 to 39) and tamped in the hole, ready 
 What a Charge is to fire. The preparation of charges is practically the 
 same for all sorts of farm blasting. The slight varia- 
 tions advisable to suit different kinds of work are not 
 enough to call for separate treatment, since the principles are all the same. 
 
 All who use Eind buy explosives should read the next chapter, beginning 
 on page 51, on the nature and actions of explosives. It is only the man who 
 understands all the facts mentioned there who will be able to load and blast 
 with greatest ease, speed and results. 
 
 Scope of This Chapter 
 
 It is important for everyone who blasts to understand why he does things, 
 as well as how to do them. For that reason the following discussion of the 
 preparation of charges is made full and complete, with due attention to all 
 the important factors involved. Details of any particular part of the operation 
 can be found quickly by referring to the heading desired, as given in the index. 
 
 Readers who may not desire a full discussion are referred to the following 
 brief outline of the process. 
 
 Be careful that explosives, cap and fuse are in perfect condition. Cut a 
 length of fuse sufficient for the hole to be loaded, making the cut clean, with- 
 out dragging ends, at a slight slant of, say, 30 to 45 degrees from right angle. 
 
 Pick a cap from the little tin cap box, carefully, with your fingers, and 
 slide it gently on the end of the fuse. With a proper cap crimper fasten the 
 cap securely to the fuse, making the crimp close to the open end of cap. Avoid 
 twisting or punching the end of fuse against the bottom of cap as well as draw- 
 ing it away from the bottom. For wet work waterproof the joint of cap and 
 fuse with tallow, soap or other material. Do not use thin grease or oil. 
 
 Next punch a hole at a long slant in the side of the stick to be primed. 
 Better use a wooden punch for the purpose. The handle of the cap crimper 
 may be used. 
 
 Insert the cap in the hole made as described, tie the fuse in place, and, 
 for wet work, waterproof all openings in the stick. You then are ready to load. 
 
 Provide space enough in the hole at the proper point to hold the required 
 amount of explosives in a bulk that is not too long. Be sure before you start 
 to press in the sticks to the bottom of the hole (see page 43) that there is enough 
 clearance to permit their easy and certain entrance. Tamp fully and firmly 
 up to the top of the hole. 
 
 The charge is now ready to fire, which may be done by pressing the burn- 
 ing or flaring head of a freshly scratched match against the powder in the split 
 end of the fuse. 
 
 Carrying Explosives and Supplies 
 
 The place to keep the explosives is in the magazine or storage place, and 
 
 not with you in the field. Carry with you in warm weather only enough for the 
 
 job or the day, or in cold weather only as much as can be 
 
 . kept warm and in condition for firing until you are through 
 
 /tt 1 • loading. Keep explosives separate from caps, 
 
 of Explosives ^ gpjjj ^j^y ^.Q j,j^j.j.y jjjg j.^pg^ fygg j^jjj gj^j^jj (.jjjjjg jj 
 
 in a basket. Put a piece of blanket in the bottom, to keep 
 36 
 
out dampness when the basket is on the ground. Some blasters use an 
 explosives box for the purpose, putting a wood handle or double wire bale on 
 it. The tight wood box probably is a little better than the basket because it 
 affords somewhat more complete protection to the contents. 
 
 Whatever the method of carrying the explosives, it should be well pro- 
 tected. This consists in keeping the hot sun off it, keeping rain and fog off 
 it, keeping it away from dampness of the ground, and keeping it safe from 
 meddlesome people and animals. 
 
 Many blasters prepare charges before going to the field, but it is better 
 practice to carry along the tools and materials, and to put them together or 
 make the primers on the spot after all the holes are made in the ground or 
 rock, and when everything is ready for the firing except to put the explosive in 
 place. 
 
 These remarks are given as reminders. Full discussion of proper handling 
 and storing of explosives can be found on pages 60 to 61 respectively. 
 
 Tools and Materials Required 
 
 The first step in preparation of charges is to assemble the following: as 
 many sticks of explosive (or parts of 
 stick, if charges are to be less than full 
 sticks) as there are holes to be primed; 
 an equal number of caps; a sufficient 
 quantity of fuse; some string; a wood 
 punch with an end the size of a cap for 
 about 3 inches; a pair of cap crimpers; 
 a pocket knife. If the holes are very 
 damp or full of water you also will need 
 some tallow or other waterproofing 
 material. In certain cases a sharp 
 hatchet or axe and a block of wood will 
 be worth having. The purpose and use 
 of these items will be made clear later. 
 
 A handy box for carrying supplies to field. 
 
 Putting Caps and Fuse Together (Maying Primers) 
 
 Fuse is described as to sizes and properties on page 60 and caps on 
 pages 58 to 60. Readers who are not familiar with them should turn to 
 those pages at this point. Unroll the fuse and cut off a length that will be 
 enough, since fuse burns about 2 feet in a minute (there are variations — see 
 page 61). 
 
 Three feet will give you IJ^ minutes or a sufficient time to get beyond 
 
 danger under ordinary conditions. The fuse, of course, must 
 
 be long enough to reach out of the mouth of the hole when the 
 
 The Fuse charge is in place. Measure the depth of the hole before you 
 
 cut the fuse. 
 
 Warm cold fuse before attempting to bend it. It may be 
 taken into any warm room for the purpose but should be subjected to no heat 
 greater than 1 1 degrees. If for any reason you have doubts about the con- 
 dition of your fuse, cut off a foot or more and try it without any cap or explo- 
 sive. If it will burn properly it is all right. 
 
 Be sure to get fresh ends both for the match and to put into the cap. If 
 fuse has been cut for some time into lengths, it is well to cut off short pieces 
 from the old ends in order to bring fresh powder right to the tips. 
 
 37 
 
Cutting the Fuse 
 
 Cut the fuse off at a very slight angle or bevel — say 30 to 45 degrees, as 
 shown in the diagram. This slant is for the purpose of giving a little space 
 between the actual end of the powder and the explosive 
 material in the bottom of the cap, to enable the spark 
 to spit into material. 
 
 The only way to regulate the space is to cut the 
 
 fuse as directed and let the long tip rest gently against 
 
 the bottom of the cap. The spark has a better chance to ignite the explosive 
 
 material in the cap when it spits from the end of the fuse than when it merely 
 
 burns up to the end without any space to spit into. 
 
 The end of the fuse where cut off should be clean and free from dragging 
 ends and threads. If it is not cut off clean, part of the covering may double 
 over the end of the fuse in the cap and keep the spark away from the explosive, 
 causing a misfire. Be careful to keep both ends of fuse off damp ground and 
 out of puddles of water. 
 
 If the fuse has been mashed, or is too thick to go into the cap easily, do 
 not peel off any of the covering. Reduce the diameter by squeezing it with 
 the cap crimpers or by rolling it on a smooth surface under a knife blade or 
 other smooth implement. Sometimes you can reduce it by rolling it between 
 the thumb and finger. 
 
 The very best way to cut fuse is on a block of wood with a sharp knife. 
 The blade can be pressed right through the fuse and will make a clean cut. 
 Another good tool is a sharp axe, to be used on a block of wood. The method 
 of cutting is of small importance, just so the actual cut is made smooth and 
 even enough. If you do use other tools, have a knife with you to trim up ends 
 that are not true. Be careful to avoid twisting, pinching or otherwise knock- 
 ing the freshly cut end of the fuse about, for you may shake out the powder 
 back far enough to cause a misfire. The powder should come out flush with end. 
 To get one cap out of the tin box in which they came, tilt the box up on 
 edge till some of the caps slide forward, and then pick the cap up with your 
 fingers. Don't attempt, on penalty of losing a hand, to take a cap out of a 
 box by running a nail or a little stick or the fuse into it in the box. Be care- 
 ful you do not drop a cap to the ground or floor. 
 
 Turn the cap upside down, to make sure there is no dirt in 
 it, and gently slide it on the fuse till the end of the fuse just 
 touches the bottom of the cap. Do not ram, press or twist the 
 end against the bottom. 
 
 Hold the fuse with capped end up, to keep the cap from 
 sliding off, and crimp the cap fast. This you do with the special plier-like 
 
 tool called a cap crimper. The 
 "crimp" is made by pinching the 
 open end of the cap 
 tight to the fuse. It 
 Crimping should be made with- 
 in the last quarter 
 inch of the open end 
 of the cap. Never make it toward 
 the closed end because you might 
 disturb the explosive material in 
 the bottom of the cap and cause it 
 
 "Crimp" or fasten caps to fuse with a regular crimp- j. ^YT^lr»rl*» 
 ing tool. This tool does the job far better than it '•" cxpioae. ^ 
 
 can be done in any other way. Cap Crimpers are Supplied by 
 
 38 
 
 The Cap 
 
all makers of explosives. Order one or more when you buy your explosive. It 
 is well to have an extra one about to use in case you lose one on extensive jobs. 
 This fastening of the fuse to the cap is one of the points in blasting where 
 a great deal of abuse occurs. Blasters think they can take a chance with danger 
 or with misfires, and attempt to crimp the caps some other way. Except in 
 extreme emergency don't try to crimp a cap with anything except a regular crimp- 
 ing tool; but there are times when one may not have a crimper nor be in a posi- 
 tion to wait till one can be purchased. There is a way out of this difficulty 
 ■ — which is to secure a makeshift crimp with something else than a crimper. 
 It is possible to use a pair of pliers, or^a small pair of pincers, and accomplish 
 something that may hold the cap on the fuse. The best makeshift crimp is 
 to take a fold of the cap up at 'one side of the mouth with a pair of close 
 fitting, square-nosed pliers. Be careful while doing this that you do not 
 grind the end of fuse against the bottom of cap, or pull the end back from 
 the bottom. If the fuse should pull away from the bottom of cap a quarter 
 inch, a misfire likely would result. 
 
 Waterproofed (tallowed) sticks ready for loading in wet holes. 
 
 When the charge is to be placed in a dry hole, waterproofing is not needed, 
 but in a wet hole the connections between fuse and cap 
 must be made water-tight with tallow or soap. Do not use 
 Waterproofing grease, because it may unite with the tar in the compo- 
 sition of the fuse cover and soften it, when the powder train 
 will be ruined. Water in the cap will surely make it worthless. 
 
 Inserting Caps in Explosive 
 
 The best location for a cap in a stick of explosive for farm blasting is in a 
 hole in the side, about an inch and a half from one end. The best position 
 for the cap at this point is at a slant that takes it in from the side toward the 
 center, but as near longways, or parallel with the sides of the stick, as possible. 
 
 39 
 
Crimping cap with the 
 cap crimper. 
 
 Fuse tied firmly to stick 
 with stiing. 
 
 Electric Blasting— Pass the 
 doubled fuze wires through 
 a bole in stick of powder. 
 
 Loop the doubled end of 
 fuze wires over end of 
 stick. 
 
 Pull loop tight, bend wires 
 at cap, punch slanting hole 
 in stick high up and round 
 to side a little. 
 
 Insert cap in slanting hole 
 to bend cf wires, take up 
 slack in wires. (Waterproof 
 boles it ground is wet.) 
 
 In cutting fuse from roll 
 use sharp knife. 
 
 Taking one cap carefully 
 {ram box. 
 
 40 
 
 Inserting fresh end of 
 {use in cap. 
 
In other words, when making the hole for 
 
 Position of the cap in the explosive, make it with as 
 
 Cap in Stick long a slant down toward the other end of 
 
 the stick as possible. There are reasons for 
 
 this connected with superior or inferior detonation. 
 
 Another style of priming much used is to set the cap 
 in a hole made in the end of the stick of explosive, and 
 then to tie the paper about the fuse or wires. This is good 
 so long as it is not damaged, but experience shows that the 
 tamping stick often bends the fuse over sharply when the 
 primed stick is pressed into the hole and sometimes even 
 interferes with the cap itself. With side priming there is 
 a cushion of the soft explosive between the end of the stick 
 and cap. End priming always is gopd provided sufficient 
 care is taken in loading to prevent disturbing or displac- 
 ing the fuse or cap with tamping rod. 
 
 When all the explosive is removed from its stick 
 wrappings, the cap must be inserted in the loose explo- 
 sive. This should be done by making a hole, as in a stick. But it seldom 
 pays to take all the explosive out of stick wrappings. Nearly always you can 
 leave a half stick of explosive intact for the cap. 
 
 Bad primins. 
 
 A good crimp. 
 
 To make the hole for the cap use the handle of the cap crimper or a 
 
 wooden punch just a little larger than the cap. The hole should be large enough 
 
 to let the cap in without much pressing, but should leave no 
 
 air space about the cap. The depth of the hole also is im- 
 
 Making Hole portant. It should be just enough so that the entire cap 
 
 in Explosive can be buried in the explosive, but not any deeper. If it is 
 
 deeper, the cap may be forced on down to the bottom, which 
 
 will leave some of the fuse in contact with the explosive 
 
 (may cause burning instead of exploding of powder), or the cap may be seated 
 
 just inside the wrapping, leaving an air space at the inside end or bottom of 
 
 the hole, which may lower the effectiveness of the explosive. 
 
 When the cap is seated in its hole in the side of the stick, the fuse will 
 
 extend up along the stick past the near end. It must be tied in this position, 
 
 so securely that the fuse and the cap will not be pulled 
 
 back in handling or by rubbing against the side of the hole 
 
 Fastening Fuse when the stick is pressed down. The best way to secure 
 
 to Explosive it is to wrap a strong string several times below the point 
 
 where the cap is inserted, then give two or three wraps 
 
 about the fuse, and pull tight and tie ; or take two loops 
 
 about the fuse and then several wraps about the stick. 
 
 Cutting stick in two — roll it under knile blade. 
 
 41 
 
When the foregoing directions have been complied with you have a stick 
 of explosive primed with a cap and fuse. It is ready to put in the hole in the 
 rock or ground. 
 
 Loading Charges in Holes 
 
 You will need a tamping stick. This must be of wood, and had better be 
 about the size of a stick of explosive, which usually will be IJ^ inches in diam- 
 eter, except in case of blockhole blasting of boulders, when a smaller stick 
 sometimes is needed to go in small drill holes. Never use a metal rod for 
 tamping. Make sure that the hole is ready. It must be big enough to allow 
 sticks of explosive to slide down easily (except in the case of small holes drilled 
 
 in rock, when the explosive all must be taken out of the 
 Tamping rod stick wrappings and crumbled and pressed into the hole). 
 
 Loose stones, sharp stones and roots that obstruct the hole 
 should be removed with a bar or spoon scraper. This work must be com- 
 pleted before starting to load. If obstructions fall into the hole, after some 
 of the explosive is in place, don't try to remove it by force. Make another 
 hole at a Seife distance from the first, put in another charge and fire it. 
 
 Measure the hole with your tamping stick and judge if there is space for 
 the required charge at the right point. Nearly always a charge of explosives 
 
 The tamping rod should be of wood. 
 
 should be as much on a pile as possible. If one or 2 sticks are all the explosive 
 
 required, it usually will not hurt to 
 put them end to end. But if 3 or more 
 sticks are required, to put them end to 
 end makes the charge too long, and 
 places the force of the blast elsewhere 
 than where it should be. 
 
 When your judgment tells you 
 that the charge should be in a more or 
 less round bulk, enlarge the hole at the 
 point where the charge should be made. 
 Sometimes this can be done by scrap- 
 ing it out at the bottom with a toe-bar 
 or spoon-bar. Again, if much enlarg- 
 ing is required, it is well to use a small 
 amount of explosive to secure it. This 
 is called springing. To do this prime 
 about a quarter of a stick as usual, 
 and push it to the bottom of the hole. 
 Use no tamping. After it is fired wait 
 till the hole cools, and you will find 
 a cavity large enough for your full 
 charge. 
 
 It is better to avoid springing 
 holes if you can, on account of the fact 
 that the cavity often is enlarged too 
 
 much, and the surrounding earth is loosened so much as to injure confinement. 
 
 (See page 51 on detonation). A great deal can be done by scraping the small 
 
 auger hole out to 2 or 3 inches in diameter at the bottom and then causing the 
 
 42 
 
 Slitting the paper wrapping of stick to let it 
 swell to fill dry hole. 
 
sticks to enlarge and fill the hole solidly. To accomplish this enlargement of 
 sticks, slit their wrappings 3 or 4 places lengthwise, from end to end. Then 
 press them home with the tamping stick. They will expand and shorten. Four 
 to 6 sticks in this way can be got into the full length of two. 
 
 Still another way is to take the explosive entirely out of the stick 
 wrappings, and with the help of a tin or paper tube, such, for instance, as 
 calendars are mailed in, funnel it down to the bottom of the hole. But neither 
 this method nor slitting the sticks is wise in wet holes. It is true that 
 nitroglycerin powders will stand considerable water, but the safe rule in wet 
 blasting is to leave the sticks intact. Ammonia powders or dynamites will 
 not stand wetting inside the paper of the sticks without damage. (Never 
 under any circumstances cut, break, unwrap or punch holes in explosive that 
 is frozen. You invite an explosion in your hands when you do). 
 
 When there is more than one stick in the charge, place the primed 
 stick on top of the others — put it in the hole last or next to last— when 
 using the cap-and-fuse method of firing. 
 
 Be sure that all parts of the charge are in firm contact. It will not do to 
 have air spaces, or dirt, or wrinkled paper between the sticks. While all the 
 powder likely would go off under these conditions, it will not do as much 
 work as it should. 
 
 The sticks of explosive may fit tightly in the holes. In that case do not 
 ram or pound them, but press firmly against them, one at a time, with the 
 tamping stick. Press the explosive into tight contact with the sides all round, 
 at the bottom of the hole. 
 
 Tamp ins 
 
 Tamping is a necessity. The charge should be tightly confined. It is only 
 in springing holes and sometimes in digging post holes that no 
 tamping is advisable, and in ditching that the quantity needed is 
 Tamping less. 
 
 When the explosive is in place at the bottom of the hole, 
 start the tamping by rolling in some loose ground. Keep the 
 tamping stick working up and down to seat this ground against the explosive, 
 though make no effort to get it tight till there is a few inches or so over the 
 explosive. An exception to this rule is in the case of blockhole blasting of boul- 
 ders and ledges, when damp clay tamping should be packed solid all 
 the way down to the explosives. The rule for the least contents of tamping 
 that will do good work is that it should be 6 or 7 times as deep as the hole meas- 
 ures in diameter. 
 
 If the tamping is less than this,'^the best results will not be secured, 
 hence deep holes often are necessary for the sake of confinement of charge as 
 well as to contain the amount of powder used. 
 
 Hold the fuse to one side with one hand while the tamping stick is worked 
 with the other hand. Rake the dirt to the mouth of the hole and be careful to 
 get in the hole only earth — not clods, sticks, grass, etc. Be very careful not 
 to damage the cover of the fuse with the tamping stick. 
 
 Fill the hole to the top with tamping, and make it tight. The best material 
 for tamping is moist clay. Tamping material always is better when made wet 
 enough to ball. In fact, there isn't much better tamping than water itself in 
 the hole, when it can be made to cover the charges deeply enough. Use the 
 heaviest earth within reach, and if it is dry, better carry some water for 
 wetting it. 
 
 43 
 
Firing 
 
 
 Stick the burning liead of a match against the 
 powder to light fuse surely. 
 
 The free end of the fuse will 
 stick out of the hole filled with 
 tamping, say about 4 inches. Your 
 remaining work is to set fire to the 
 powder in the fuse, till it begins to 
 spit continuously. Split the end of 
 fuse with your pocket knife to 
 make it light easily. Put the flar- 
 ing head of a freshly scratched 
 match against the powder exposed 
 by the cut. 
 
 Preparing Charges for Electric Firing (Maying Primers) 
 Up to this point in the directions for preparing charges the text has spoken 
 only of caps and fuse. When the firing is to be done with an electric blasting 
 machine instead of fuse, you must use electric blasting caps. 
 
 These come from the makers with the wires already fastened in them. 
 (See pages 59 and 60.) They are ready to be inserted in the stick of explosive 
 without any preparation such as ordinary caps and fuse require. 
 
 Make a slanting hole in the stick of explosive just as is described on page 
 41. Into this insert the electric blasting cap, letting its wires project 
 just as the fuse does when fuse is used. Then tie the wires to the stick with a 
 string as fuse is tied, to prevent the cap from being pulled partly or entirely 
 out of the hole. 
 
 Bad method of fastening wires. 
 It is better to tie them. 
 
 Bad position of cap in stick, and of cap wires. 
 
 It is a little difficult to tie the wires tight enough with a string to prevent 
 slipping. Another way to fasten them securely is to pass the wires through 
 the stick. To do it punch a hole straight through the stick of explosive about 
 the middle. Double the wires about 6 inches back of the cap and pass the 
 doubled end through this hole. Then loop the doubled ends from the other 
 side back round the lower end of the stick. Take up the slack in the wires 
 and you will have a sure fastening. The cap can be inserted in the stick at 
 another point, in a slanting hole, just as described previously. 
 
 In fixing wires of electric blasting caps to sticks, avoid crossing them and 
 avoid bending them sharply or in any manner that will break their insulating. 
 If the insulating is broken it likely will cause a short circuit, which will result 
 in a misfire. Never take a half hitch about the stick i/^ith the wires. Do not pull 
 at the wires and the cap, because to do so may break the fine bridge wire that 
 causes the cap to explode when the current goes through. 
 
Load these primed sticks the same as is directed for fuse primed charges. 
 Be careful to avoid rupturing the insulating on the wires with small stones in 
 the hole or with the tamping rod. 
 
 The finishing of the tamping leaves two wires projecting from each hole. 
 They must be connected with the blasting machine or other source of current 
 with connecting wire and leading wire, in the manner described fully on pages 
 55 to 57. Further discussion is not needed at this point. 
 
 Some General Suggestions 
 
 In priming sticks of explosive with fuse and blasting cap, you must be 
 careful to avoid permitting the fuse to touch the explosive. High explosives 
 will burn like gasoline or coal-oil. They are very easily set on fire by sparks 
 spitting from fuse. When they are burning the explosion will be very much 
 weaker than it otherwise would be, and will give off noxious gases. 
 
 A very frequent cause of misfires is the bending, kinking and crooking of 
 fuse. This is especially frequent when the cap is inserted in the center of the 
 end of the stick of explosive and then carelessly forced over against the side of 
 the hole by the tamping stick and tamping material. Keep the fuse straight, 
 and never under any circumstances lace it through the stick of explosive. That 
 is a sure cause of trouble. 
 
 If it becomes necessary to remove a cap from a primed stick of explosive, 
 do it gently and carefully, and unless the cap and fuse are immediately to be 
 inserted in another stick, destroy them both by lifting a shovelful of earth 
 and putting the cap under the ground in the hole, zifter which light the fuse 
 and go away. 
 
 It is better not to lift or carry the primed stick of explosive by the fuse 
 or wires when it can be helped. When a practice of carrying primed sticks 
 by the fuse is made, misfires and poor explosions will be caused, not every 
 time, but often enough to make it wiser not to do so. The cap often is pulled 
 back in spite of the tie string. 
 
 Where explosives that are subject to water damage are used in work that 
 is wet, matters can be helped by making the sticks waterproof with tallow, 
 paraffine or other suitable material. It is practicable to stop all the seams on 
 the sticks, load and fire without delay, even with explosives that would be 
 put out of business if the water got at the actual material instead of only at 
 the wrappings of the sticks. Pay particular attention to waxing or tallowing 
 the place where the cap and wires go into the stick. 
 
 When doing wet blasting, use every care to keep the outer end of the fuse 
 from dropping into the water or from resting on damp ground. The inner 
 wrappings of fuse and the powder train itself take up water like a blotter. On 
 a very foggy day it is well to keep fuse in a closed box. Mist and rain of 
 course, will damage it. 
 
 45 
 
Explosives and Blasting Supplies 
 
 The catalogs of manufacturers are not intended to give all the fundamental 
 facts about and the differences between the various explosives. To do so 
 would take too much space. They give the trade names and the measure- 
 ments and weights of sticks and boxes, demanded by purchasers, and are pre- 
 pared on the supposition that blasters and buyers of explosives know what 
 they need. This bulletin includes explanations of the names under which 
 blasting explosives are made and marketed, outlines their properties, and makes 
 clear the work and conditions for which each grade is intended and suited. 
 
 Explosives 
 
 There are scores of different kinds of explosives made and used for blast- 
 ing purposes, and many dozens of different names used for them. The most 
 familiar name of any explosive in America is dynamite. Another 
 familiar term is powder. Other names are farm powder, quarry 
 Names powder, contractor's powder, coal powder, stumping powder, Jud- 
 son powder, gelatin, blasting gelatin, R. R. P., giant powder, blast- 
 ing powder and dozens of others. 
 Nearly every one of the explosives designated by these names are made 
 in several strengths, and in qualities to suit varying conditions. For this rea- 
 son figures and other marks are attached to the names to distinguish the grades. 
 In addition to this some of the names are used to designate not only one cer- 
 tain explosive but several widely different ones. This is particularly true of 
 the names dynamite and powder. The selection of names in the preceding 
 paragraph is made for illustrative purposes, and is not to be taken in any sense 
 as a recommendation of those explosives for any purpose. The recommen- 
 dations are given in detail on other pages. 
 
 AH blasting explosives are not made from the same ingredients, and they 
 differ a great deal in many other ways than in quality, as quality is generally 
 understood. You can buy cornmeal that is good, bad or indifferent, but when 
 you buy explosives you will find there are few which can be 
 classed as of poor quality. Nearly every standard kind and 
 Differences grade is of excellent quality for some particular purpose and 
 condition. And practically every one can be classed as of poor 
 quality for conditions and purposes to which it is not suited. 
 Nor is the difference one of size of stick or grain, as the case may be, though 
 this is one element. The main differences are ones of strength, quickness or 
 speed of gases, sensitiveness, resistance to cold and to water, density, fumes 
 and cost. Some explosives are suitable for wet work, and others only for dry 
 work; some are adapted to blasting hard, tough rock, others to blasting ground 
 only; some freeze when chilled a little; others can be exposed freely without 
 freezing. And it should be noted that many of the better explosives of to-day 
 have been developed during recent years and are comparatively new. The ex- 
 plosive to buy for any particular work is the best one on the market for all 
 the conditions involved. 
 
 Black blasting powder has been known and used for several hundred 
 years, and it is practically the same to-day as it has been for a long time. It 
 is composed of saltpeter or nitrate of soda, sulphur and char- 
 coal. It does not vary in strength, and varies little in other 
 Explosive properties. 
 
 Ingredients The dynamites and high explosive powders have little or 
 
 no relation to black blasting powder. They depend for their 
 explosive force on other explosive chemicals the best known of 
 46 
 
which are nitroglycerin and ammonium nitrate. It is not necessary in this 
 brief description to name additional explosive elements. 
 
 The first dynamite was made in Europe by mixing nitroglycerin with a 
 light spongy earth, and packing the mixture in paper tubes as sticks of dyna- 
 mite and powder are ps^cked to-day. Nitroglycerin itself is a wonderfully ef- 
 ficient explosive when it can be controlled, but it is so dangerous and unstable 
 that it must be mixed and treated to make it safe enough to handle. 
 
 As other explosive chemicals become better understood, it has been found 
 of advantage to substitute materials that are explosive for the light earth used 
 to absorb the nitroglycerin. And more than that, the nitroglycerin itself has 
 been displaced to varying degrees in some of the powders and dynamites by 
 ammonium nitrate and other materials. Few blasting explosives contain no 
 nitroglycerin at all, but many contain only 4 or 5 per cent, of it. Each of these 
 combinations of materials, or formula, has its own peculiarities in addition to 
 variation in strength, all of which information it is well for a buyer and blaster 
 to understand. 
 
 The explosives marketed as "straight dynamites" and "straight powders" 
 are made from nitroglycerin. Those made from an ammonium nitrate base 
 are called by many manufacturers "extra" dynamites and powders. Gelatin 
 dynamites and blasting gelatin are nitroglycerin explosives in which the nitro- 
 glycerin has been combined with gun cotton. The various special mine, quarry, 
 stumping, farm and other miscellaneous dynamites and high explosive powders 
 on the market are not so named that their ingredients can be determined with- 
 out a statement from their makers. 
 
 The power of an explosive and its violence are two different qualities. 
 
 The power, or direct strength, is due to the volume of the gases. If a pound 
 
 of a certain explosive gives, for instance, 1,000 cubic feet 
 
 of gas when completely detonated or fired, while a pound 
 
 Strength and of another explosive gives 500 cubic feet and a pound of a 
 
 Quickness third gives 2,000, the lifting power of each explosive will 
 
 be in direct proportion to its gas volume. 
 
 But the violence of the gases depend, not on their 
 volume, but on their speed. If they are comparatively slow in forming and in 
 forcing their way out of their confinement they will break out large cracks 
 and escape through them, pushing the material aside. If they are very fast 
 or quick, they will grind and pulverize everything they come in contact with, and 
 throw out the whole side of the confining material, but will not crack it so far. 
 
 The matter can be made clear by comparing a push with a blow of a hanmier. 
 Both may have equal power, but the effects on a block of wood, for instance, 
 at the point where they are applied are very different. The push will move 
 the object almost without marking it. The blow may move it, but it is sure 
 to leave a mark of greater or less depth, depending on the nature of the ham- 
 mer and its speed. A still better comparison, perhaps, is that between the blow 
 of a sledge and of light hammer. It is possible to hit a blow of as much power 
 or weight with one as with the other, but the material at the point where the 
 blow lands with the light hammer will be badly dented, or maybe broken. 
 The reason is that the light hammer moves with much greater speed. 
 
 In quarries blasters make use of these facts in order to get the rock broken 
 out in pieces of the size preferred. When they want large pieces they use an 
 explosive with sufficient power to break the rock, but, comparatively speaking 
 with a slow speed of gases ; when they want small pieces and much shattering, 
 they use an explosive of the same or greater power but with swift and violent 
 gas action. 
 
 47 
 
For each result and for each material a certain power is required and a 
 certain quickness of the gases is best. By way of illustration, take soil blasting for 
 tillage purposes. There is no object in violently grinding the earth at one spot 
 while surrounding earth that might be reached is left untouched. A proper 
 explosive for this purpose is one that will have enough pulverizing action, 
 that will lift and shake up the soil, and that extends its effects for long distances. 
 For an example of the other extreme, take mud-capping rocks. For this work 
 the explosive cannot be too violent in action. The gases, backed up by the 
 rapidly yielding wall of air behind them, must strike the rock a crushing blow 
 in the minimum of time. 
 
 Nitroglycerin and ammonia powders and dynamites, for all practical pur- 
 poses, are of equal strengths when of equal markings. The strength is indi- 
 cated accurately by percentage figures. 
 
 Nitroglycerin explosives are uniformly quicker and more violent in action 
 than ammonium nitrate explosives, and the more nitroglycerin there is in the 
 explosive the quicker it is. The ammonia explosives are not as quick, in any 
 strength, as the corresponding nitroglycerin explosives. Therefore a 50% 
 nitroglycerin powder is more violent than a 50% ammonia powder, and a 
 20% ammonia powder is much less violent than a 50% grade. 
 
 When the object is to shatter and reduce to fine fragments the material to 
 be blasted, the proper explosive is a quick one, while when the object is to 
 lift and shake up the material the best explosive is a slow one. (See table on 
 page 50, also detailed recommendations on pages 22 and 25.) But there 
 are other factors that must be considered. 
 
 Nitroglycerin explosives resist water better than ammonia explosives, but 
 if the cartridge wrappings are not broken or opened, ammonia dynamite or 
 powder can be loaded in wet holes with entire satisfaction. The firing should 
 not be delayed any longer eifter loading than necessary, and it is wise to plan 
 the work so that it may be done at the longest within a half hour sifter loading. 
 Storage in a damp place will weaken explosives, especially ammonia explosives. 
 
 Gelatin explosives resist water very well, and may be loaded in wet holes, 
 or under water, with assurance that they will explode with their full power. 
 Blasting gelatin is entirely water-resisting. 
 
 Explosives will freeze, and when in this condition are dangerous, and can- 
 not be fired properly, if at all, with a cap of any kind. They must be thawed 
 and they must be handled very carefully if they are to be used. On no account 
 attempt to cut the wrappings, to break a stick, or to handle the frozen explo- 
 sive in the ordinary way. (See pages 51 and 52 for directions for thawing.) 
 
 Regular nitroglycerin explosives are quickest to freeze. Others, known as 
 "Low Freezing," will stand much lower temperatures without 
 showing trouble in this respect. 
 Freezing Ammonium nitrate explosives also will freeze, but not quite 
 
 so quickly as nitroglycerin explosives. They too are made on 
 both regular and low freezing formulas. The low freezing am- 
 monia will stand more cold than the low freezing nitroglycerin. 
 
 The regular explosives will freeze at temperatures of 45 to 50 degrees. 
 The low freezing explosives will not freeze and become solid till the thermome- 
 ter gets down to at least 25 degrees, and in practice many of them can be used 
 right out in the open without any trouble when the temperature is down to 
 zero and below. The length of time the powder is exposed to the cold has 
 much to do with its freezing. 
 
 The safety point for both low-freezing explosives and regular explosives 
 is not a matter of rule, but of watching the explosive. When high explosive 
 
 48 
 
powder or dynamite is frozen, the sticks will be hard, and when it is 
 partly frozen they usually will have a mottled appearance on outside of the 
 paper wrappings. The hardness may only be in spots. When not frozen, the 
 sticks should be a little soft all over. No explosives should be handled much, 
 cut, punched, rubbed, broken or loaded when they are frozen. They can- 
 not be exploded satisfactorily and such acts are. dangerous. 
 
 In cold weather always use the low freezing grade of explosives, for the 
 regular grades may freeze in the holes before they can be fired. It is a good plan 
 to use the stronger caps, say No. 8 (see page 50) in cold weather. When 
 a charge of explosive is chilled but not frozen it can be fired satisfactorily by a 
 heavier impulse (blow and heat) than ordinary, such as a fresh No. 8 cap gives. 
 The low freezing explosives do not differ in action from the regular explosives, 
 and are just as efficient. 
 
 The gases of explosives naturally are more or less objectionable when 
 breathed. Some of them are poisonous, others are merely disagreeable. When 
 explosives are used out in the open the gases are taken up by the air so quickly 
 that none of them give any serious trouble, though they do cause headaches. 
 It is only in tunnels and deep shafts where the air is confined that the matter of 
 fumes is important, not on farms. 
 
 Special explosives have been developed for tunnel and mine work, but they 
 are not important in agricultural work. The only fact about fumes worth know- 
 ing in farm blasting is that nitroglycerin explosives either 
 in the form of their gases or when absorbed through the 
 Other Properties skin will cause headache somewhat quicker than ammonia 
 explosives. The so-called fumeless explosives always cost 
 more than any ordinary dynamites and powders and are 
 not suited to farm work. Farmers will do well to buy grades of explosives 
 suited for their special purpose. 
 
 Dynamites and most high explosive powders are light-colored materials 
 that look like fine, sticky sawdust, and they always are packed in "sticks" 
 made with cylinders of tough paper. These sticks vary in 
 diameter and length. The standard is \]/^ inches in diameter 
 Appearance and 8 inches long. This is the size carried in stock by dealers 
 of Explosives and in the magazines of the makers. You can get special 
 sizes of sticks if you need a considerable quantity, varying 
 from J/i of an inch in diameter to 4 inches. Sizes other than the standard 1 J^ 
 by 8 inch may cost more per pound than the standard owing to higher pack- 
 ing cost. 
 
 Dynamites and high explosive powders are packed in wooden boxes con- 
 taining 25 pounds or 50 pounds, as you prefer. A 50-pound box of 20 % ammonia 
 powder or dynamite will contain about 105, IJ^ by 8 inch sticks. If of 20% 
 nitroglycerin, it will contain about 98 sticks. If of gelatin dynamite, or blasting 
 gelatin, it will contain about 88 sticks. 
 
 A word should be said here about the cost of explosives. No quotations can 
 be given because the prices vary in different parts of the country and from time 
 to time. The ammonia products usually are cheapest. The cost of course 
 follows the percentage strength, the low percentages cheaper and the high per- 
 centages dearer. Gelatin explosives cost about the same as straight nitroglycerin 
 explosives. The special explosives for use in mines, tunnels, quarries, railroad 
 construction work, etc., often cost more than the explosives recommended 
 here for farm work. 
 
 In buying explosives look first to getting the one that is best suited 
 to the work to be done, and aside from that the cheapest one. There 
 
 49 
 
 '0 
 
would be no object in using a straight nitroglycerin or a gelatin explosive when 
 one of the ammonia farm powders would do the work, for the former explosive 
 cost much more than the latter. 
 
 To avoid "explosive misfits" it is well to consider carefully the nature of 
 the material to be blasted, the conditions of weather, water, etc., and the results 
 wanted. The kind of explosives to use depends on these factors. Keeping in 
 mind the facts mentioned in preceding paragraphs, the reader will see that there 
 is a type of explosive made for almost every condition and kind of work, and 
 will understand why one will not suit the work of another. 
 
 As the briefest and clearest way of giving general suggestions for the type 
 of explosive best for different agricultural work, a table follows: (Detailed 
 recommendations are given on pages 21 and 25.) 
 
 Explosives Recommended for Different Wor\ 
 
 Stone blasting — mudcap Straight nitroglycerin or ammonia dynamite, 
 
 50% or 60%. 
 Stone blasting — undermine ... To break, same as for mudcapping; to throw 
 
 out, use any dynamite or powder of 20 % strength. 
 Stone blasting — blockhole .... To shatter well, any high percentage dynamite 
 
 or powder; to break into large pieces, 20% 
 ammonia dynamite or powder. 
 Soil blasting — for subsoiling 
 
 and for tree planting. ... 20 % ammonia dynamite or powder. 
 
 Ditching — electric firing 20% to 40% ammonia explosives; (nitroglycerin 
 
 is equally effective); in loose dry ground, high 
 percentage nitroglycerin explosives. 
 Ditching — transmitted detona- 
 tion Straight nitroglycerin dynamite or powder, 50 % 
 
 strength. 
 Stump blasting — in mediunS 
 and heavy soils, wet or 
 
 dry 20 % nitroglycerin or ammonia dynamite or 
 
 powder. 
 Stump blasting — in dry sand 
 
 and other light soil 50% nitroglycerin or ammonia dynamite or 
 
 powder. 
 If you are in doubt as to the best explosives for your particular work it is 
 well to write to the manufacturer you prefer, asking which of their grades and 
 brands would be most suitable. 
 
 Detonation 
 
 It is well known that black powder is fired by a spark, and that dynamites 
 and high explosive powders cannot be fired by a spark but require a shock and 
 heat. It is not so well known that there are great dif- 
 ferences in the nature and effect of the explosion of any 
 Filing, Exploding powder or dynamite, due to variations in the way it is 
 or Detonating fired. 
 
 An explosion of powder or dynamite is the result of 
 
 a very sudden creation of a great volume of gas from a 
 
 smaller volume of powder. The kind and amount of gases produced by any 
 
 50 
 
high explosives depend on the kind and amount of shock used to fire the charge, 
 and on its confinement. 
 
 The effect of lighting a piece of unconfined dynamite with a piece of fuse 
 without a cap on, is that the dynamite will burn fast without exploding and make 
 a dense smoke which has a bad smell and produces severe headaches. This is 
 simple combustion. If the piece of dynamite is confined closely and lighted in 
 the same way it will explode, but will give off similar bad fumes. If a weak cap 
 is used on the fuse, or the dynamite is set off by a fall, the dynamite will be 
 partially detonated, and explode with considerable force, but it still will give 
 off the bad fumes and smoke. The same piece of dynamite fired with a No. 6 
 or 8 cap will be completely detonated, and will explode with great violence and 
 force, even when unconfined, except by air, and will give off very little smoke. 
 
 The last-named explosion is detonation. It is produced by a violent shock 
 in connection with intense heat. Nitroglycerin is 5 times as strong as black 
 blasting powder when exploded by fire, and 1 times as strong when detonated. 
 This explains the enormous force given by detonation as compared to simple 
 explosion. 
 
 But detonation itself is no set thing that always takes place the same. 
 There is good, or complete, or full detonation, and there is partial detonation. 
 In case of incomplete detonation, or any detonation at a less speed than the 
 greatest for any particular explosive, the gases formed are not what they should 
 be. For one thing, they are more noxious or poisonous. The more powerful 
 and severe the blow delivered by the cap, the more quickly does the chemical 
 action take place in the explosive. It is only when high explosives detonate 
 with their greatest speed that their maximum power is generated. 
 
 Air spaces about the cap in the stick of explosive cushion its blow and weaken 
 detonation. It is the nature of the initial detonation of the powder right around 
 the cap which governs the nature of the explosion of the whole charge. A blaster 
 should understand the importance of setting up complete detonation in order to 
 get the greatest amount of force out of explosives. Sometimes explosives lose 
 as much as 20% of their effectiveness when fir^d with weak caps. Lack of 
 confinement has a similar effect. Sixty per cent, dynamite poorly detonated 
 is less effective than 40 % well detonated. 
 
 When explosives become chilled it is difficult to detonate them properly 
 with the usual cap, hence the advisability of using a very strong cap in cold 
 weather — a No. 8. Many of the holes are frequently loaded for some time 
 before firing, and even if the powder is soft and normal while charging, it after- 
 wards becomes somewhat chilled in the cold ground. 
 
 Throughout this and other bulletins in this series, the 
 
 terms caps and electric blasting caps are used in speaking 
 
 Cap Means of the exploders used to fire the charges of dynamite or 
 
 Detonator powder, although in the field and among manufacturers 
 
 the same articles are called by the terms "detonators," or 
 
 "electric exploders." 
 
 Thawing Explosives 
 
 It has been pointed out (on page 49) that regular explosives chill or freeze 
 at temperatures of 45 to 50 degrees. With the increase in the number of low 
 freezing explosives that seldom need thawing, the necessity for doing the 
 thawing on farms is not as frequent as it used to be. 
 
 Frozen dynamites and powders are dangerous materials, and whenever 
 the temperature is near the freezing point for them, the sticks should be 
 
 51 
 
inspected before using to see if they show any of the hardness that indicates 
 
 chilling. If so, handle them very carefully till they are thawed. Dynamites and 
 
 high explosive powders will be a little soft to the pressure 
 
 of your thumb when they are not frozen. 
 
 Frozen Explosive Frozen explosives are dangerous because they are 
 
 very much more easily exploded in the course of ordinary 
 
 handling. They are more sensitive to friction and to 
 
 blows of tools. The sticks may explode when dropped to the ground or 
 
 floor, when sticks are broken in two, when wrappings are cut with a knife, when 
 
 cap holes are punched with a stick, or when they are shoved into a hole with a 
 
 tamping stick. At the same time they are so much less sensitive to the direct 
 
 shock of a detonating cap that they cannot be fired properly with a cap. 
 
 Therefore the rule must be laid down that frozen sticks of high explosives never 
 
 must be cut or ruptured or used until they are thawed. 
 
 When nitroglycerin freezes it crystallizes, therefore the nitroglycerin in 
 dynamite or powder tends to separate from its absorbing materials into small 
 crystals. When the dynamite is thawed slowly with sticks lying on their sides, 
 the nitroglycerin is reabsorbed as fast as it liquefies. But when thawed too 
 fast, the nitroglycerin is liable to run out of the sticks before it is reabsorbed. 
 Quick thawing will damage explosives a great deal more than they would be 
 damaged by freezing followed by long, gradual thawing. 
 
 Thawing is a dangerous operation when not done 
 right. It probably is correct to state that more acci- 
 dents with dynamite have occurred in the course of 
 improper thawing than for all other reasons put to- 
 gether. At the same time proper thawing is entirely 
 safe. 
 
 Two of the most frequent causes of accidents while 
 thawing explosives are in putting the sticks into water or 
 steam, and putting them on hot stoves or stones. 
 Water, and especially hot water, forces the nitro- 
 glycerin out of the sticks. The free nitroglycerin goes 
 One type of thawer on to the bottom, and explodes at the time of the first 
 ™*' ° ■ increase in heat, or first light blow. When sticks of 
 
 explosives are laid on hot material the nitroglycerin also runs from the paper 
 wrappings and drops of it fall to the stone or 
 Causes of metal. This almost always causes an explosion. 
 
 Accidental Explosions At about 350 F. degrees of heat, which is only a little 
 more than that of boiling water, the nitroglycerin 
 will explode without a shock. 
 
 Examine your explosives a day or so before you are ready to use them, 
 and if they show that they are frozen, proceed to thaw 
 them in one of the following ways: Use only a DRY 
 
 Safe Thawing warmth. Use no temperature higher than is comfortable 
 to the hand, or the limit may be set at 100 or 110 degrees. 
 Use no heat of any kind that cannot be controlled with 
 
 certainty. If you do this you will be safe. 
 
 Every large maker of explosives will supply thawing apparatus that is 
 safe. Sometimes this is a double kettle arranged so that the sticks of explosives 
 can be placed in the inside vessel, while the outside vessel can be filled with 
 warm water and a blanket can be spread over the top. Other more elaborate 
 thawers consist of a vessel containing watertight tubes just big enough to hold 
 
 52 
 
sticks of explosive, running through a space to be filled with warm water. The 
 catalogs describe these ready-made thawers in detail. 
 
 Home-made thawers can be arranged with two buckets, one small enough to 
 hang inside the other. Put the sticks inside the small one and warm water around 
 the outside, in the big bucket. Another good way is to put a five-gallon can of 
 warm water inside a barrel, or box, and pile the sticks of explosives in the barrel 
 around the can. The top of the barrel should be covered with a blanket. Or 
 put the water in the barrel and the explosives in a can or bucket. A small 
 closet of course can be used instead of a barrel. A can of warm water can be set 
 inside a magazine to keep the temperature up. 
 
 The old-fashioned manure pile method of thawing is reliable and Scife, though 
 a good deal of trouble. This consists in burying a box somewhat larger than a 
 box of explosives in fresh horse manure, and placing inside it the box of explo- 
 sives to be thawed. A foot or more of manure must cover the box, and a small 
 pipe or tube should be inserted for ventilation. The manure must be fresh. 
 Allow at least 1 hours to thaw a box of dynamite or powder in this way. Twenty 
 hours is better. 
 
 The box of explosives can be taken into any warm place that is dry, but if 
 
 this is a building you must take your own risk of fire and accident. Watch the 
 
 box and the sticks to see if the freezing and thawing causes the sticks to leak 
 
 free nitroglycerin. If any of this leaks out of the stick and 
 
 gets on the floor it must be washed up according to direc- 
 
 Sticks on Sides tions in paragraphs on storage. (Pages 61 and 62.) The 
 
 sticks of explosives had better be piled irregularly rather 
 
 than in tiers, for thawing. They will rise in temperature 
 
 quicker in this way. They always must lie on their sides rather than stand 
 
 on end. 
 
 Electric and Fuse Firing 
 
 The very best way to light fuse is to split the end for an inch or less, 
 and stick the burning head of a 
 freshly scratched match right against 
 the exposed powder at the head of 
 the split. This will light the fuse 
 even in a strong wind. 
 
 Where there are very many 
 fuses to light in succession, as in 
 subsoiling, it some- 
 Fuse and times is of advantage 
 Cap Firing to use a gasoline or 
 other torch, holding 
 the hot flame under the fuse for an instant. Whatever the method, do not 
 leave till you see the fuse spitting sparks and smoke swiftly and regularly. 
 Further discussion of fuse firing, except as to its adaptations, is not needed. 
 Farmers who have only a few stones or stumps to blast, 
 or who are planting a few trees or doing a little subsoiling. 
 Electric Firing will not need any other method of firing than by caps and 
 fuse. Ditch blasting in ground not watersoaked demands 
 electrical firing, while the blasting of large stumps, particu- 
 larly if green, and in sandy soil, as well as the blasting of large rocks, is made 
 easier and cheaper by electrical firing. For large amounts of almost any blasting 
 except that of tree beds, subsoiling and very small stumps and isolated small 
 
 53 
 
boulders, the purchase of an electric blasting machine and the necessary wires is 
 justified by the advantages of the electric methods of firing. 
 
 The primary reason 
 for the superiority of 
 electric firing over fuse 
 firing is that several 
 charges may be explod- 
 ed at once; the different 
 charges will increase 
 the effi- 
 ciency of 
 Advantages each other. 
 Thus in 
 ditching, 
 you can fire many 
 charges in a row and 
 
 A good reel for leading wire. 
 
 make a perfect ditch. In stump blasting several small charges very often 
 will take a stump out better than one large charge, and in orchard, and 
 garden subsoiling the simultaneous blasts frequently are of advantage. 
 
 Electric firing is more certain when the charges are under water. The 
 danger from misfires due to moisture as well as from some other cause is reduced. 
 Should misfire occur, you are safe in going to the charges as soon as the wire 
 is disconnected from the blasting machine. With a fuse you must wait some 
 hours to be safe. When several charges, as for instance, several boulder blasts 
 are to be fired, you can make one trip to safety do for the lot, instead of having 
 to travel back and forward for each shot. Finally, the intelligent and careful 
 use of electric firing, with its possibilities of two or more small charges doing the 
 work of one large one, and its other economies, will save considerable ex- 
 plosives. 
 
 All the makers of explosives supply electric blasting machines. The ma- 
 chines are small boxes of wood or metal, containing a modified magneto with a 
 
 handle on top that you either push down or pull up, 
 depending on the make of machine, to operate and 
 Electric Machine to fire the charges. The machines are made in vari- 
 
 ous sizes and capacities to fire 3, 10, 30, or more 
 charges at once. The 10 charge machine weighs 
 about 10 pounds. Full directions for operating and caring for the machines 
 always accompany them. 
 
 For electric firing, in addition to the machine, you will need electric blasting 
 caps, connecting wire and leading wire. The leading wire is copper wire large 
 
 Duplex Leading Wire. (Actual size.) 
 
 enough to carry the amount of current required for the number of charges to be 
 fired simultaneously. It is covered with insulating material, and is made strong 
 
 and durable to stand much use. To make the circuit from the 
 Wiring blasting machine to and through the charges and back again, 
 
 you must have two strands of leading wire. It comes from the 
 
 54 
 
explosive makers in single-strand 
 form, which must be doubled, and 
 in what they call duplex form, which 
 has two strands of insulated wire 
 twisted together or wrapped to- 
 gether under one cover. 
 
 The two small copper wires that 
 are fixed in the electric blasting caps 
 ( see page 59) should be long enough 
 to reach out of the holes. They may 
 be bought in a 
 Electric variety of lengths. 
 
 Blasting Caps but 4 or 6 feet 
 
 are regarded as Connecting wire comes on spools. 
 
 Standard. If the charges are close enough together so the wires can be con- 
 nected, no cormecting wire will be needed; but whenever the distance between 
 is more, the charges must be connected, and connecting wire is the right thing 
 to do it with. There is no particular limit for the distance between charges 
 that may be connected for firing together, up to 25 feet or more. 
 
 A very bad connection — a cause of misfires. 
 
 Good connection for electric cap wires. 
 
 Good connection for small cap wires and large leading wire. 
 
 The diagrams in these pages will show how to make electric wire connections. 
 Cut away the insulating on the wire ends and wrap the ends together tight. 
 Wrap them for two inches. Looping the wires will not do. Be careful to 
 scrape with a knife or stone the wire ends to make them bright before wrap- 
 ping them together. Corroded or dirty connections are a cause of misfires. 
 
 If the leading wire gets broken and must be 
 Wire Connections spliced, solder the connection after wrapping the 
 
 ends together, then wrap the joint with tape to 
 55 
 
Tape for wrapping joints and broken insulating. 
 
 insulate it. Ordinary tire-tape is good, but a better way is to wrap the joints 
 
 with special rubber tape under- 
 neath and to cover this with the 
 tire-tape. 
 
 When only one charge is to 
 be fired, connect the ends of the 
 2 strands of the leading wire to 
 the 2 electric blasting cap wires 
 and connect the other leading 
 wire end to the blasting machine 
 posts. The connection with the 
 electrical blasting machine should 
 be made the last thing before firing, after you are sure that the charges are all 
 ready and after every person and animal is out of the way of the flying pieces. 
 When the blast is all connected together ready to fire, except attaching the 
 leading wire to the machine, give the handle of the machine one or two light 
 strokes, to make sure that it is working smoothly and to charge the magnets. 
 Then attach the leading wires to the binding posts on the machine, making 
 sure that both the binding posts and the wires are bright and clean where they 
 come together. Raise the handle of the machine to its full height and push it 
 down with speed. When the handle starts on its downward stroke, the pinion 
 immediately clutches the armature and starts the generation of current. The 
 current, growing stronger as the stroke proceeds, causes considerable resistance 
 toward the end of the stroke. The current generated is directly in proportion 
 to the speed with which the handle is pushed down, especially just before reach- 
 ing the bottom. Any let up toward the bottom will cause a drop in the current 
 and may result in misfires. Therefore, make it an invariable rule, whether the 
 shot be large or small, to bang the handle down hard and carry the stroke with 
 all possible speed to the bottom. Try to knock the bottom out of the box. 
 Machines which operate by the twisting of a handle must be handled equally 
 quick. 
 
 Very best wire connection, ready for soldering if need be. (Excellent for leading wire.^ 
 
 When more than one charge is to be fired the different charges must be 
 connected together. The diagrams will help you to understand how this should 
 be done. For nearly all agricultural blasting the connection in one series is the 
 best — that is, connecting each charge to the next one and so on until they are 
 all joined, with one loose electric blasting cap wire from the two end charges 
 of the series. (See diagram A and D, page 57.) 
 
 Once in a while, where the series is long and the charges are in a line, you 
 can arrange to have the 2 loose wires at the same end of the series by making 
 the connection, not to each next charge in the row, but to the one beyond and at 
 the farther end doubling back and connecting the missed charge. Do not use 
 this method where it involves many splices with connecting wire. 
 
 Connections in parallel sometimes are desirable in the case of ditches, or 
 other extensive blasting. To make them run a piece of wire away from one lead- 
 ing wire strand along the lines of charges and connect one wire to each charge. 
 Then run another similar piece of connecting wire connected to the other strand 
 of leading wire, and attach to it the other cap wire of each charge. 
 
 But to fire charges by means of parallel connections takes so much electric 
 current that a blasting machine cannot be used. Generally speaking, parallel 
 
 56 
 
MimTOV^li^-lr 
 
 ^■^'■'■''■^^-^'SlIT-S 
 
 
 sz 
 
 MUMMfia 
 
 a*""*™""^' 
 
 Stfaig^i 3eneS cannectt'on for 
 US& i/i/f'ih blasting machine 
 
 O Multiple -Series used with both 
 blasting machine and power-current 
 
 Method of wrapping wires together to make electrical joint, and of taping joint. 
 
 connections require current from an electric light or power plant. If your 
 work is such that the charges cannot be connected in series or that parallel 
 connections are desirable, it is well to communicate with an expert or authority 
 on electricity for special sugges- 
 tions and advice as to how best 
 to fire your charges. 
 
 In a bulletin of this size it is 
 impossible to give a comprehen- 
 sive statement of 
 Current electric firing. But 
 
 Reqtiired to give some idea, 
 it can be stated 
 that an electric blasting cap re- 
 quires 1 to 1 J^ amperes to insure 
 firing. This amount of current will 
 fire one cap or many in a series. 
 To force this amount of current 
 through the wires requires a 
 certain voltage, the amount de- 
 pending on the size and length of 
 all the wires, and on the joints. 
 One bad or poorly wrapped joint 
 will increase the resistance of the 
 circuit more than several caps. 
 The voltage of the current re- 
 quired to fire any circuit usually 
 can be computed by an expert 
 when the details of the wiring 
 system are explained to him. 
 
 When charges are connected 
 in parallel, instead of series, or in 
 multiple series (see diagram C), 
 each circuit requires 1 to 13^ 
 amperes of current. That is, each 
 cap requires \ to Xy^ amperes 
 when connected in parallel. The 
 voltage required, of course, de- 
 pends on the resistance of the 
 wires. A very much greater cur- 
 rent than of 1 to 1 3^ amperes will 
 do no harm; in fact it is desirable. 
 
 Electric blasting machines 
 are constructed to give a suffi- 
 cient amperage and voltage for 
 
 ^ Three wire system with three-post 
 blasting machilne 'B' used with two-post 
 machine is better 
 
 f\ - Parallel connection, used lA/ith 
 electric light or power-current 
 
 G^ ftro c/cCrmB/ars in o ' rwo detonatois " "^ "^ ' ' — **" 
 
 a/Ki/e, mnve/inseries. In Bho/e.tvinnjin G' ^/iing up seperare hales 
 notsosoodnijiaraffel. para/iefi best lynji in scries, not i^sommem/eii. 
 
 0^ hvo detoneCais 
 
 G.:.. Combinations of para/ie/ circuits 
 when fir/ns witii .electric liAbt or 
 power current. 
 
 Ways of connecting up cliarges for electric firing. 
 
 57 
 
^•^ESte 
 
 Two post electric blasting 
 
 machine — push down 
 
 type. 
 
 firing properly the number of caps specified as the capacity of the machine 
 when connected in a series. If too many caps, or more than usual wiring 
 is connected to any machine, misfires will result. Other current can be 
 used in place of that supplied by a machine, provided it 
 has enough and not too much amperage and voltage. 
 Too great a current will burn out wires without firing all 
 the charges. Too little current sometimes will do the 
 same, or it may do nothing. In emergencies dry cells or 
 wet batteries can be used by skillful operators to fire a 
 few charges, when great care is taken to have the wiring 
 arranged for the purpose. Before attempting to fire 
 charges with batteries of any kind, learn the amperage 
 and voltage of their output and see that your shots come 
 within their limits. The use of batteries is more ex- 
 pensive than the use of electric blasting machines. 
 
 Bare connections at the charges or back along the 
 leading wire should be raised off the ground by stones, 
 sticks or piles of dirt placed under insulated parts of the 
 wires at each side of the splice. During a thunder storm, do 
 not stand near any of the charges that have been connected. Avoid dragging the 
 leading wire over bare or rough ground as much as possible, and particularly avoid 
 kinking it. Be careful not to break or tear or scratch the insulating of any wires. 
 Do not attempt to fire through a long length of leading wire wound in a coil 
 or on a reel. The induction, leakage or short circuit of current in the coil 
 of wire causes the blasting machine to deliver a slow discharge, which is fatal io 
 proper firing. Leading wire that is watersoaked or that is covered with mud 
 will lose a considerable part of its current. 
 
 Misfires 
 
 Nearly half of the accidents noted each year in blasting operations are the 
 result of attempting to examine misfires too soon. If misfires occur with fuse 
 firing, stay away from the shot at least 2 hours. It is better to wait until the 
 next day, for the spark may linger 24 hours and still cause an explosion. (See 
 page 60.) Rock and stump misfires are to be avoided especially. When you are 
 firing the charges electrically, you may approach the shot with entire safety as 
 soon as the lead wire is discormected from the blasting machine. 
 
 Misfires are due to the following named causes. The remedies for them are 
 care in preparing the charges and in loading, the details of which are given in 
 the proper chapters. 
 
 With cap and fuse firing, misfires are caused by having the end of fuse 
 pulled back a little from the bottom of the cap, by crimping the fuse too tightly 
 with a groove crimp and shutting off the spark, by damp or wet fuse, especially 
 at the end of the cap, by defective cap, by the cap getting pulled out of the 
 explosive, by kinked, damaged, broken or pinched fuse, by failure to light fuse. 
 A great many misfires were never fired at all. With electric firing the reasons 
 for misfires may be damaged wires in the hole, causing short circuits, defective 
 caps, overloaded blasting machine, cap pulled out of explosive, bad wire con- 
 nection at some point, or broken wire. 
 
 If you find after due time that for some reason the charge cannot be fired 
 by lighting the old fuse or by sending current through the wires, you must deal 
 with a real misfire. 
 
 The best thing to do is to put in another, lighter charge in a new hole made 
 6 to 1 2 inches of the original one. The explosion of the new charge will explode 
 
 58 
 
the old one. Never touch the tamping in the old hole unless you know just how 
 deep it is, or how many inches of it there are above the charge. Once in a 
 while the tamping may be dug out of a blockhole misfire. It seldom pays to do 
 this in stump blasting, and never in ditching, or soil blasting. At best it is a 
 dangerous operation. Mudcap charges can be opened and new primers inserted 
 without danger or difficulty. This should be done by removing part of the 
 mud at another point, and inserting a new cap and fuse, or electric blasting 
 cap, as the case may be. 
 
 Cap (Detonators) 
 
 Blasting caps are little copper tubes closed at one end, 1 3^ to 2 inches long 
 and something less than a quarter of an inch in diameter. At the bottom is 
 placed several grains of a high explosive that is very powerful and exceedingly 
 sensitive to heat, shock and friction. This high explosive usually is fulminate 
 of mercury, but often is other 
 material. They are packed in small 
 tin boxes, open end up, usually 1 00 
 to the box. 
 
 The purpose of the blasting 
 cap is to supply the shock and heat 
 necessary to detonate the charge 
 of dynamite or powder to be fired. 
 If it were not for safety in handling 
 blasting explosives, they all could 
 be made as sensitive as the material 
 in the caps. But such explosives 
 would be impossible to handle 
 without accident. In fact, it would 
 be impossible to handle the little 
 bit of explosive in the caps if it 
 was not protected by the copper 
 shells. Even at that caps must be 
 kept free from jars and from heat 
 and sparks to avoid premature 
 explosion. 
 
 The strength of caps is care- 
 fully regulated by the makers to 
 fire the dynamites and powders on 
 the market. The explosive material 
 with which the caps are loaded is such as will deliver a shock and a degree of 
 heat of the strength and violence required. The caps are numbered according 
 to strength. All dynamites and powders used for agricultural blasting require 
 at least a No. 6 cap. If they are chilled a little, but not frozen, they require 
 No. 8. It is the part of wisdom to use No. 8 caps all the time if you can get 
 them. They give you a margin of strength should moisture or other causes 
 weaken them in storage. 
 
 Blasting caps must be used with fuse. And before they are inserted in the 
 stick of explosive they must be fixed to the fuse properly. (See pages 37 to 40.) 
 It is the spark which travels down the fuse that fires the cap. 
 
 Electric blasting caps are made on the same principle as ordinary blasting 
 caps. They have the copper tube, the explosive at the bottom, etc., but they 
 differ in the way this explosive is fired. Instead of by a powder spark they are 
 fired by a red-hot wire that is heated by an electric current. 
 
 59 
 
 D and E are ordinary blasting caps ; F and G are 
 electric blasting caps, often called fuzes. 
 
Electric blasting cap or fuze. 
 
 Every electric blasting cap has fitted in it 2 small copper wires, which 
 must be considered part of the cap. Down near the bottom of the cap is a deli- 
 cate bridge of finer wire. The entire arrangement is held in adjustment and 
 sealed by a casting of sulphur-like substance. 
 
 The interior construction of an electric blasting cap or fuze. 
 
 For fuse blasting you must use regular blasting caps, and for electric blasting 
 you must use electric blasting caps. It is impossible to substitute one for the 
 other. Never pull at the wires in an electric cap. It is dangerous and may loosen 
 or throw out of adjustment the arrangement of wires inside. And never try to 
 dig out the wires of an electric cap or to dig or to punch the explosive in the 
 bottom of a blasting cap. 
 
 Fuse (Safety Fuse) 
 
 Fuse is used for firing black blasting powder and for firing dynamite and 
 high explosive powders through the medium of a cap. It is made by. enclosing 
 
 within a covering a train of special 
 black powder and an inflammable 
 cotton string. The spark runs 
 down this powder train. 
 
 The powder used in fuse is 
 specially made for the purpose, is 
 pulverized and is highly compressed 
 by the covering of the fuse. The 
 covering itself is made of varying 
 materials, depending on the condi- 
 tions under which the fuse is to be 
 used. For dry work it is only 
 enough to hold the powder in place 
 and to keep the powder train from 
 getting broken. For damp and wet 
 work it is made waterproof by in- 
 Fuse as it comes in rolls. creasing the number of layers in 
 
 the covering and by adding varnish, coal tar, as other waterproofing material. 
 There are many brands of fuse on the market. In buying fuse you must 
 bear in mind the character of your work. For work that is en- 
 Grades tirely dry you can use ordinary cotton or hemp fuse with satis- 
 faction, if it is large enough to fit a blasting cap snugly. 
 For work in damp ground, use a fuse in which the cotton or hemp is covered 
 with one layer of waterproof tape or other material. This is called single-tape 
 grade or may',be known by brand name only. For work where the ground is 
 wet, such as in stump and stone blasting in damp or wet weather, use a double- 
 covered fuse— fuse that has two layers of tape or other material over the cotton 
 
 60 
 
covering and waterproofing material added. For work where water covers the 
 charges it is best to use fuse with three layers of tape or other material and 
 full waterproofing. This is called triple-tape fuse or may have special brand 
 names. When buying fuse for general farm work, it is well to get a water- 
 proof grade, since it can be used for both wet and dry work. 
 
 Most reliable fuse burns about 2 feet per minute when in perfect condition. 
 
 If it becomes damp, it burns much slower. Cases have been known 
 
 where the spark smouldered in damp fuse for hours without 
 
 Rate of traveling more than a few inches. Another source of uncertainty 
 
 Burning is where fuse has been pinched. It may take the spark a minute 
 
 or an hour or a day to get past the pinched point. 
 
 When fuse is cold, it is hard and brittle, and may crack open 
 when unrolled. If it gets too warm, its waterproofing material may penetrate 
 to the powder train inside and ruin it; or the covering may first soften and then 
 harden, in this condition breaking as though cold when unrolled. If grease is 
 allowed on the cover it may combine with the waterproofing and ruin the 
 powder inside. 
 
 Handling Explosives 
 
 Dynamites and powders in boxes can be hauled freely in spring wagons. 
 You should see that no bolt heads or other metal parts project from the wagon 
 boxes to strike the boxes of explosives. Sweep all dirt out of the wagon. Have 
 the beds clean or covered with straw or blankets. 
 
 Go over your wagon and harness before you load dynamite to make sure 
 they will not break down while you have the explosive aboard. Be sure you 
 have the hitching straps or tie-ropes along, and do not leave the horses standing 
 without tieing them securely. Break no colts while hauling explosives. If 
 you use a motor, stop it and set the brake tight before you leave the load. 
 In driving through a town stay away from dangerous crossings. 
 
 Keep the sticks of explosive in their original boxes until you are ready to 
 use them. Don't have them around loose. In carrying them to the field, use 
 a wood basket or a box and not a metal bucket. Always protect explosives from 
 all possibility of being reached by falling sparks or from match heads or Other 
 source of fire. Rain, hot sun and the like must be kept away from explosives. 
 Use care to lay sticks or set the boxes or baskets containing explosives where they 
 will not fall down, be blown over by wind or knocked over by careless people 
 or by animals. Cattle will eat sticks of dynamite, or powder, because of their 
 sweet and salty taste. The explosive will make them sick, sometimes kill them. 
 
 Since nitroglycerin often will cause headache when absorbed through the 
 skin it is best to wear gloves when handling the sticks. For this same reason 
 some people punch holes for caps in the sticks with a piece of wood rather than 
 with the handle of the cap crimper. 
 
 Caps should not be carried in the same basket or box as explosive, but should 
 be carried separately. Take only enough along to do the work in view and 
 carry them in the tin boxes they come in. Many serious accidents have been 
 caused by blasters having loose caps in their pockets during work or afterwards. 
 Sooner or later a chance jar is likely to set them off. When several caps have 
 been taken out of the little tin box in which they come the rest will be loose and 
 will rattle about. This should be stopped by filling up the empty space with 
 paper. 
 
 The handling of caps is not dangerous provided you do it intelligently and 
 with care. Keep them safe from any jars or heat. You can sometimes do 
 
 61 
 
many foolish things with dynamite and powder without 
 
 serious results to yourself, but not with caps. Letting a cap 
 
 Handling fall to the ground or floor likely will cause it to explode. For 
 
 this reason you should keep the caps and explosives apart, 
 
 in hauling, storing, and handling, bringing them together 
 
 only at the last minute before you prepare the charge to be loaded in the hole. 
 
 One cap cein produce an explosion powerful enough to tear your hands off. 
 
 Electric blasting caps must be handled with the same care as regular 
 blasting caps. All caps must be protected from dampness during handling. No 
 trouble will be experienced if you use common sense at every turn, but thought- 
 lessness and carelessness in the handling of explosives will cause disaster. Bear 
 in mind that when an accident happens with an explosive there is no time to 
 save yourself, and no afterthought will prevent serious injury to you. Fore- 
 thought is the thing with explosives. In an explosive you are handling an enor- 
 mous strength. The fact that it occupies small bulk now should not interfere 
 with your imagining it as an enormous engine with power enough to crush you 
 easily, but under entire control if you do your part right. 
 
 Storing Explosives and Supplies 
 
 The storing of dynamites and powders on farms offers no serious problems, 
 though it may call for some shifting of arrangements to meet proper require- 
 ments. The explosive must be kept dry. They should be kept cool. This means 
 that any ordinary temperature of the air is all right, except that in hot weather 
 the room where the explosive is kept should not get warmer than 80 or 90 
 degrees. If it is properly ventilated day and night it will not. Probably the 
 best common storage place for explosive is in an outbuilding under the floor of 
 which the air circulates freely and with a ceiling between the room and the roof. 
 It should be strong, and should be provided with a lock. A responsible person 
 should have charge of the key at all times. 
 
 The explosive should not be kept in a garret, because the hot sun beating 
 down on a roof will raise the temperature under the roof away past the 100 
 degree mark. 
 
 Dampness is injurious to explosives, as noted on page 48, and dynamites 
 and powders must be kept where moist air will not surround them. The ideal 
 storage would be fireproof, but since this is out of the question on the average 
 farm, the best that can be done in that respect is to guard against fire. It is 
 well to make sure that the explosive is out of reach of any stray or malicious 
 bullet that might be fired into it. 
 
 Look to your insurance policies and see whether they provide against the 
 storage of explosives in any of your buildings. Store the explosive in a building 
 not covered by the insurance. 
 
 Where large quantities of explosives are to be stored as a regular thing, 
 
 or for any length of time, it is advisable to consult the makers 
 
 of explosives or others experienced in their handling in regard 
 
 Magazines to the location and construction of a magazine. A magazine 
 
 can be set up cheaply and can be made fireproof, bullet proof, 
 
 thief proof, well ventilated, dry and safe in every way. It 
 
 should be built of brick. Any explosive maker will furnish plans without 
 
 charge. In any case explosives should be stored at least 50 yards away from 
 
 any other buildings and from roads or railroads. 
 
 62 
 
Blasting caps of any kind must not be stored with dynamite or powder. 
 
 Fuse is not explosive and can be stored with dynamite or powder. 
 
 /-. Blasting caps are even more subject to damage by moisture than 
 
 ^ explosive and must be stored'accbrdingly. Caps must not be allowed 
 
 to become heated. 
 
 A statement of the ways in which explosive deteriorates will help in 
 
 selecting a proper storage place for it. In temperatures higher than 80 degrees 
 
 troubles may begin. Long continued temperatures of 
 
 90 to 100 degrees may cause the nitroglycerin to leak 
 
 Deterioration out of the absorbing material and to gather inside the 
 
 wrapping on the lower side of the sticks, or may even 
 
 cause it to leak out of the wrappings through the 
 
 boxes and to the floor. 
 
 Strict watch should be kept of the sticks and the boxes to catch any such 
 condition. If leakage occurs, turn the explosive over and reduce the temper- 
 ature. Burn the empty boxes one or two at a time out away from buildings, 
 and scrub the floor where the leakage occurred with a strong solution of sal 
 soda. This will decompose the nitroglycerin. If it becomes necessary to de- 
 stroy a little explosive without detonating it, the job can be done by immersing 
 it until dissolved in such a solution, stirring it gently with a wood paddle. 
 
 If the sticks feel smeary it is possible they are leaking. The test is to lay 
 them on white paper for a little while. If they are leaking they will stain the 
 paper, otherwise not. 
 
 At a temperature of 105 degrees nitroglycerin explosives will lose 10% of 
 their strength in a few days by evaporation. Repeated freezing and thawing 
 is bad for explosives, especially if the thawing is rapid. Slow thawing will not 
 damage them much. After explosive once is frozen and thawed, it will freeze 
 much easier again. 
 
 When stored for many months explosives are liable to decomposition of 
 some of their elements, especially if they get damp or too warm. One of the 
 marks of this is greenish stains inside the stick wrappings. No length of time can 
 be stated for the keeping of explosives, because it practically all depends on 
 conditions. Under favorable conditions most dynamites and powders will re- 
 main in good shape for years. Again, a month of improper storage will ruin 
 them and make them dangerous to handle. They develop troubles sooner in 
 the light than in the dark. 
 
 Deteriorated explosives are likely to be dangerous — ^far more so than normal 
 explosive. Keep watch over what you have in stock. Maintain proper conditions 
 as far as possible, but if they show troubles do not hesitate to condemn them. 
 
 Shipping Explosives 
 
 The shipping of high explosives is controlled by the Interstate Commerce 
 Commission, and the rules and regulations are very strict and rigid. Most of 
 them are embodied in an Act of Congress of March 4, 1 909, and violations are 
 punishable with fines of not more than $2,000, or imprisonment for not more 
 than eighteen months, or both. The person making the shipment is 
 responsible. 
 
 A copy of the rules and regulations can be secured from the Bureau of 
 Explosives, Underwood Building, New York City, or can be read at any freight 
 station where there is an agent. 
 
 The rules provide that no explosives (other than certain exceptions named) 
 shall be carried on any train, boat, trolley, or other vehicle carrying passengers 
 
 63 
 
for hire, and that no explosives under deceptive or false markings or under- 
 standing shall be delivered to a common carrier; and further, that all other 
 regulations shall be complied with. 
 
 In shipping by railroad no caps or detonators of any kind can be sent in 
 the same car with explosives. In practice the railroads usually send them by 
 another train, which works out to be another day in the cases of nearly all 
 shipments. This is responsible for some delay in delivery of explosive ship- 
 ments. Do not expect to have explosives come through as quickly as you would 
 other freight. 
 
 Explosives cannot be shipped by express or by mail, but are sent by 
 freight, the same as groceries or dry goods. The railroad company is required 
 to place the packages in a certain way inside the car and to brace them with 
 lumber. In case of car-lot shipments the shipper must furnish this lumber and 
 do the bracing. 
 
 The regulations provide that railroads must have 24 hours' notice of ship- 
 ment of explosives, and that shipments must be removed from the receiving station 
 within 24 hours of their arrival there. The packages must be plainly stenciled 
 with the name of shipper and consignee, and bills of lading must conform with 
 certain specifications. 
 
 Empty boxes which once have contained explosives must never again be 
 used for shipments of any kind. Farmers who have attempted to ship vegetables 
 or other farm products in such boxes have unwittingly gotten themselves into 
 trouble on account of this regulation more than once. 
 
 Danger and Safety 
 
 Modem explosives have been developed to the point where they need not 
 be feared by anyone who handles them intelligently. Speaking in a comparative 
 way, they may be used with no greater dangers than there is in the using of 
 horses, mowers, traction engines, sawmills, or other farm equipment, or than 
 there is in using shotguns or rifles. 
 
 The general use of explosives on farms is so new that many people dis- 
 trust them more because of their newness than from a clear understanding of 
 any actual dangers their use may hold. A review of what the dangers are may 
 help users of explosives to avoid them, and may help to build up the reader's 
 belief in the safely of explosives. 
 
 There is some danger in the handling and transporting of explosives, but 
 it depends very largely on the exposure of the dynamite or powder to heat, 
 flame, sparks, blows and friction. The directions say to keep explosives dry, 
 to keep them at a temperature less than 90 or 100 degrees F., to keep them 
 safe from sparks, and to avoid blows and shocks. If these directions are followed 
 there will be few accidents. 
 
 Probably the most common cause of accidents with explosives lies in 
 violation of some of these primary rules while thawing frozen sticks of dynamite 
 or powder. Freezing makes the high explosive less sensitive to the simple 
 direct shock of a blasting cap, unaccompanied, as it is, by any friction. But at 
 the same time freezing makes the explosive more sensitive to friction in any form. 
 
 For this reason, though a frozen stick of dynamite cannot be fired properly 
 by a blasting cap, it is very likely to be fired prematurely by a chance light 
 blow from any object touching it, by your slitting the wrapping paper with a 
 knife, by breaking the stick in two, or by attempting to punch a hole into it to 
 insert a cap. (These operations are entirely safe when the explosive is normal.) 
 If the stick is dipped in warm water or exposed to steam, or is laid on anything 
 which is warmer than about 125 degrees, free nitroglycerin likely will leak out 
 
 64 
 
and fall in drops. And one drop of nitroglycerin falling only a few inches may be 
 exploded itself and may explode all dynamite that is near it. 
 
 Throughout the entire course of handling the explosive, from the freight 
 station to the hole in the stone or the ground, you should remember the five 
 cautions which will be repeated: Keep it dry, keep it cool, keep it away from 
 sparks and flame, and keep it saie from blows and friction. Be careful — as 
 careful as you would in driving a big automobile or a traction engine. Then 
 you will be secure from any accidents, and explosives will be entirely safe to 
 handle. 
 
 65 
 
INDEX 
 
 Page 
 
 Accidents 52, 53 
 
 Ammonia explosives 48 
 
 Amount of explosives required 30, 31 
 
 Augers, Soil 33 
 
 Blast ditch. How to 20, 21. 32 
 
 Blasting machine 35, 54, 57 
 
 Blasting, Possibilities and limits of 14, 15 
 
 Boxes of explosives 49 
 
 Breaking sticks of explosives 41 , 42 
 
 Burning of explosives 45 
 
 Buying explosives 49 
 
 Capacity of ditch 9, 19 
 
 Caps and fuse. Putting together 37, 39 
 
 Caps, Blasting... 51, 59 
 
 Caps, Electric blasting 59, 60 
 
 Caps, Position in sticks 39, 40, 41, 44 
 
 Carrying explosives 36, 61 , 62 
 
 Charge, What it is 36, 45 
 
 Chilled explosive 48, 51 
 
 Cold weather blasting 24, 27, 48, 51 
 
 Conditions demanding drainage 6 
 
 Connections, Wire 55, 56, 57 
 
 Cost of ditch 9 
 
 Cost of explosives 49 
 
 Crimping caps 38, 39, 41 
 
 Current required to fire charges 67 
 
 Cutting sides of ditch 3, 1 1 , 25 
 
 Cutting sticks of explosives 41, 42 
 
 Danger 64 
 
 Depth for charges 28 
 
 Depth of ditch 16, 18, 28 
 
 Deterioration of explosives 63 
 
 Detonation 50 
 
 Detonators 51, 59 
 
 Difference in explosives 46, 49 
 
 Ditches, Blasting of 20 
 
 Ditches, Example of blasted 29 
 
 Ditches, Methods of making 12, 15 
 
 Ditches, Size of 16, 18, 19, 28 
 
 Ditches, When needed 6 
 
 Draining 6, 9, 10. 12 
 
 Dry ground.- II, 22, 25 
 
 67 
 
Page 
 
 Dynamite, General properties 49 
 
 Dynamite, Grades and types of 21, 25, 46, 47, 50 
 
 Dynamite, Kinds recommended 22, 25, 50 
 
 Dynamite, Low freezing 48 
 
 Dynamite, Names and brands of 46, 50 
 
 Dynamite, Removing wrappings from sticks of 41, 42 
 
 Dynamite to use 22, 25, 50 
 
 Electric blasting caps 44, 51, 55, 59, 60 
 
 Electric blasting caps inserted in sticks 40, 44 
 
 Electric firing advantages 54 
 
 Electric firing. Wiring required for 54, 55 
 
 End priming 41, 44 
 
 Essentials of good ditching 9 
 
 Explosive, Ingredients 46 
 
 Explosive, Required amount of 30 
 
 Explosive, Required per charge 31 
 
 Explosive, Removing paper from sticks of 41, 42 
 
 Explosives, Frozen 48, 49, 51 
 
 Explosives, Low freezing 48 
 
 Explosives, Names of 46, 47 
 
 Explosives, Properties of 46, 49 
 
 Explosives, Quickness of 47 
 
 Explosives recommended 50 
 
 Explosives, Strength of 47, 48 
 
 Explosive, To use 22, 25, 50 
 
 Finishing ditch 34 
 
 Firing ditch blasts 21 
 
 Firing electric 2 1 , 53 
 
 Freezing of explosives 48, 49, 51 
 
 Fumes 49 
 
 Fuse and caps, Putting together 37, 39 
 
 Fuse, Cutting of 37, 38 
 
 Fuse, Description of 37, 38, 41 , 60 
 
 Fuse fastening to sticks of explosive 40, 41 , 45 
 
 Fuse length 37 
 
 Fuse lighting 44, 53 
 
 Fuse safety 60 
 
 Fuzes 44, 51, 55, 59. 60 
 
 Fuzes, Priming with 40, 44 
 
 Gases, Nature and volume of 47, 49 
 
 Grade of ditch 9, 16, 17, 18 
 
 Grass, Blasting ditch through 3, 11, 25 
 
 Gravel, Making holes in 27 
 
 68 
 
Page 
 
 Ground, Dry 1 1. 22, 25 
 
 Ground, Nature of 10, 21, 22, 23, 25, 27 
 
 Ground. Wet 15, 25 
 
 Handling explosives 61 
 
 Hang fires 45, 58 
 
 Headache prevention 61 
 
 Holes for charges in ground 26, 28 
 
 Holes in sticks of powder. Making 40, 41 
 
 Ingredients of explosives 46 
 
 Laying out ditch 1 6, 20 
 
 Length of blast transmitted. Method 22, 23, 24, 27, 28, 51 
 
 Length of fuse 37 
 
 Lighting fuse 44, 53 
 
 Line of ditch 16, 17, 18 
 
 Loading charges 42, 43 
 
 Locating lines for holes 26 
 
 Low freezing explosives 48 
 
 Magazines 62 
 
 Methods of draining 12, 15 
 
 Misfires 45, 58 
 
 Names of explosives 46 
 
 Nature of ground 10, 22, 24 
 
 Nitroglycerin explosives 22, 25, 48 
 
 Open ditches 1 3, 24 
 
 Packing of explosives 49, 63 
 
 Parallel wire connections 56, 57 
 
 Powder, General properties of 49 
 
 Powder, Grades and types of 22, 25, 46, 47, 50 
 
 Powder, Low freezing 48 
 
 Powder, Removing wrappings from sticks of 41, 42 
 
 Powder, To use 22, 25, 50 
 
 Preparation of ground 25 
 
 Primers, Making 37, 40, 44 
 
 Priming center charge 25 
 
 Priming sticks 37, 39, 40, 41. 44 
 
 Propagated ditch blast (see transmitted firing) 25 
 
 Protection of explosives 36, 61 , 62 
 
 Punching hole in stick 41 
 
 Punching sticks for caps 40, 41 
 
 Quickness of explosives 47 
 
 Rod, Tamping 42 
 
 Roots in ground 3, 1 1 , 25 
 
 Safety 64 
 
 69 
 
Page 
 
 Safety fuse 60 
 
 Sand 10, 11. 22, 23 
 
 Sand, Holes in 27 
 
 Season for ditch blasting 27 
 
 Series wire connections 57 
 
 Shipping explosives 63 
 
 Side priming 39, 44 
 
 Size of ditch 16, 18, 19, 28 
 
 Slitting stick of explosive 42 
 
 Sod 3, II, 25 
 
 Soil auger 33 
 
 Soil, Dry 1 1, 22, 25 
 
 Soil, Nature of 10, 21, 22, 23, 25, 27 
 
 Soil, Wet 15, 25 
 
 Spacing charges 21 , 23 
 
 Spoiling of explosives 63 
 
 Spreading earth from ditch 27 
 
 Sticks, Appearance and size of 48, 49 
 
 Sticks of powder. Breaking or cutting 41, 42 
 
 Sticks, Removing wrappers 41, 42 
 
 Storing explosives 36, 61 , 62 
 
 Stream channels 7, 8, 16, 28, 29 
 
 Strength of explosives 47, 48 
 
 Tamping 27, 43 
 
 Tamping rod 42 
 
 Tape 56 
 
 Temperature of ground 24 
 
 Test loadings 21 , 23, 31 
 
 Thawing explosives 5 1 , 52 
 
 Tile draining 1 2, 35 
 
 Time required 32 
 
 Tools required ' 33, 37 
 
 Transmitted firing 22, 23, 24, 27, 28, 51 
 
 Value of ditches 6 
 
 Violence of explosives 48 
 
 Waterproofing charges 27, 39, 45 
 
 Weakening of explosives 63 
 
 Wet ground 15. 25 
 
 Width of ditch 16, 19, 28. 29 
 
 Wind influence 27 
 
 Wire connections 55. 56. 57 
 
 Wiring for electric blasting 54, 57 
 
 Wrapper. Removing from stick 41 , 42 
 
 70