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Bureau of Mines Information Circular/1985 
 
 Critical and Strategic 
 Minerals in Alaska 
 
 Tin, Tantalum, and Columbium 
 
 By J. Dean Warner 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 
 CD 
 
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 'W/NES 75TH A^ 
 
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 Information Circular 9037 
 
 A 
 
 Critical and Strategic 
 Minerals in Alaska 
 
 Tin, Tantalum, and Columbium 
 
 By J. Dean Warner 
 
 UNITED STATES DEPARTMENT OF THE INTERIOR 
 Donald Paul Hodel, Secretary 
 
 BUREAU OF MINES 
 Robert C. Horton, Director 
 
As the Nation's principal conservation agency, the Department of the 
 Interior has responsibility for most of our nationally owned public lands 
 and natural resources. This includes fostering the wisest use of our land 
 and water resources, protecting our fish and wildlife, preserving the 
 environmental and cultural values of our national parks and historical 
 places, and providing for the enjoyment of life through outdoor recreation. 
 The Department assesses our energy and mineral resources and works to 
 assure that their development is in the best interests of all our people. The 
 Department also has a major responsibility for American Indian reserva- 
 tion communities and for people who live in island territories under U.S. 
 administration. , „ • 
 
 Library of Congrats Cataloging In Publication data 
 
 Warner, J. Dean 
 
 Critical and strategic minerals in Alaska. 
 
 (Bureau of Mines information circular; 9037) 
 Bibliography: p. 8 
 Supt. of Docs, no.: I 28.27: 
 
 1. Tin— Alaaka. 2. Tantalum — Alaska. 3. Niobium — Alaska. I. Title. II. Series: Infor 
 madon circular (United States. Bureau of Mines; 9037. 
 
 TN295.U4 (TN271.T5) 
 
 622 s 
 
 (553.4'53'09798] ?f g™"""* 
 
 For sale by the Superintendent of Documents, U.S. Government Printing Office 
 Washington, DC 20402 
 
Ill 
 
 CONTENTS 
 
 O 
 
 o 
 
 Page 
 
 Abstract 1 
 
 Introduction 2 
 
 Acknowledgments 2 
 
 Definitions 2 
 
 History, production, and reserves 2 
 
 Tin 2 
 
 Tantalum and columbium 4 
 
 Bureau of Mines investigations 4 
 
 Trends of Alaskan tin occurrences 4 
 
 Alaska Range 4 
 
 Yukon-Tanana 4 
 
 Kuskokwim 5 
 
 Kokrine-Hodzana 5 
 
 Seward Peninsula 5 
 
 Northeast Alaska and Brooks Range 5 
 
 Other areas with tin occurrences 5 
 
 Page 
 
 Tin lode occurrences 5 
 
 Greisen 5 
 
 Vein 5 
 
 Skarn 5 
 
 Pegmatite 6 
 
 Volcanogenic massive sulfide 6 
 
 Tin placer occurrences 6 
 
 Regional features of Alaskan tantalum and 
 
 columbium occurrences 6 
 
 Tantalum and columbium lode occurrences 6 
 
 Tantalum and columbium placer occurrences 7 
 
 Summary 7 
 
 References 8 
 
 Appendix. — Listings of lode and placer occurrences 
 
 of tin, tantalum, and columbium in Alaska 11 
 
 ILLUSTRATION 
 
 1 . Tin. tantalum, and columbium occurrences in Alaska in pocket 
 
 TABLES 
 
 1 . Estimated production of tin from lode and placer sources in Alaska 3 
 
 2. Tin reserves in Alaskan lode and placer deposits 3 
 
 A-1 . Lode occurrences 11 
 
 A-2. Placer occurrences 15 
 
IV 
 
 UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 
 
 ft 
 
 foot 
 
 ft 2 
 
 square foot 
 
 in 
 
 inch 
 
 lb 
 
 pound 
 
 lb/yd 3 
 
 pound per cubic yard 
 
 Ib/yr 
 
 pound per year 
 
 m 
 
 meter 
 
 mg 
 
 milligram 
 
 mi mile 
 
 MM lb million pounds 
 
 MMyr million years 
 
 oz/ton ounce per ton 
 
 pet percent 
 
 ppm part per million 
 
 yd 3 cubic yard 
 
CRITICAL AND STRATEGIC MINERALS IN ALASKA 
 Tin, Tantalum, and Columbium 
 
 By J. Dean Warner 1 
 ABSTRACT 
 
 Alaska contains many critical and strategic minerals that are scarce in the conterminous United 
 States. Among these are tin, tantalum, and columbium. This Bureau of Mines report summarizes 
 available data on the production, reserves, and occurrences of these minerals in Alaska. 
 
 Alaska produces about 200,000 lb of tin per year, with historical production since 1 901 estimated 
 to have totaled 5,830,600 lb. Measured, indicated, and inferred tin reserves total over 140,o6o,000 lb. 
 Much of the tin production has been from the placer mines of the western Seward Peninsula; 
 however, most of the reserves are in that area's lode deposits. 
 
 Alaskan tin occurrences are part of a belt of tin mineralization that extends along the western 
 coast of North and South America. The Alaskan portion of this "tin belt" comprises placer occurrences 
 and lode occurrences of five major types: greisen, vein, skarn, pegmatite, and volcanogenic massive 
 sulfide. Greisen and vein occurrences are the most abundant, but skarn deposits have historically 
 been the most economically important. 
 
 Columbium and tantalum have not been produced in Alaska; however, they may be recoverable 
 as byproducts of tin, tungsten, gold, or uranium mining. Approximately 1 35,000 lb of columbium oxide 
 (Cb 2 5 ) are inferred within the Tofry placer deposits in the Manley Hot Springs district. 
 
 ' Geologist. Alaska Field Operations Center. Bureau of Mines, Fairbanks, AK. 
 
INTRODUCTION 
 
 Alaska has frequently been a source of tin, tungsten, 
 platinum-group metals, antimony, mercury, chromite, and 
 small amounts of asbestos during periods of national 
 shortage, including the First and Second World Wars and the 
 Korean and Vietnam conflicts. In a program that is part of the 
 mineral studies mandated under the Alaska National Interest 
 Lands Conservation Act (ANILCA), 2 the Bureau of Mines is 
 evaluating occurrences of critical and strategic minerals in 
 Alaska. The objective of this program is to locate deposits 
 
 that could be mined if a prolonged national shortage should 
 develop. Field work undertaken in 1981 concentrated on 
 cobalt, platinum-group metals, and chromite (1). 3 This report 
 presents findings from the second phase of the Bureau's 
 critical and strategic minerals program in Alaska; it summa- 
 rizes information on tin, tantalum, and columbium production, 
 reserves, and occurrences. This information is meant to 
 serve as a basis for future field and laboratory research. 
 
 ACKNOWLEDGMENTS 
 
 The mineral occurrence map (fig. 1, in pocket) and the 
 mineral occurrence data presented in this report were 
 compiled principally from the published sources listed in the 
 reference section and from the computerized files of the 
 Bureau of Mines Minerals Availability System (MAS). In 
 addition, the following companies provided prospect informa- 
 
 tion and/or assisted the author in obtaining prospect 
 information: Anaconda Minerals Co., Bear Creek Mining Co., 
 Duval Corp., Patino, Inc., and Tenneco Minerals Co., 
 Anchorage, AK; Resource Associates of Alaska, Inc. and 
 Doyon Ltd., Fairbanks, AK; Billiton Exploration, Inc., Denver, 
 CO; and Union Carbide Corp., Grand Junction, CO. 
 
 DEFINITIONS 
 
 This report uses the following definitions: 
 
 Occurrence - The verifiable presence of a mineral or 
 minerals. 
 
 Prospect - A mineral property, the value of which has not 
 been proved by exploration. 
 
 Deposit - A natural occurrence of a useful mineral of 
 sufficient extent and degree of concentration to invite 
 exploration. 
 
 Mine - An opening or excavation in the earth for the 
 purpose of extracting minerals. 
 
 Cassiterite (Sn0 2 ) is the most abundant tin mineral and 
 the only tin-ore mineral produced in Alaska. Some reports of 
 tin production list pounds of concentrate, some pounds of 
 cassiterite, and some pounds of tin metal. In this report, 
 unless otherwise noted, concentrate is assumed to contain 
 75 pet Sn metal, which is essentially the same as the tin 
 content, by weight, of cassiterite. This assumption probably 
 results in a slight overestimation of total tin production, but is 
 used as an upper limit for the tin content of concentrates 
 where no specific information is available. 4 
 
 HISTORY, PRODUCTION, AND RESERVES 
 
 TIN 
 
 Tin was first reported in Alaska in 1900 by A. H. Brooks 
 of the U.S. Geological Survey (USGS), who identified 
 cassiterite in placer concentrates from Buckner Creek and 
 the Anikovik River on the Seward Peninsula (2-3). Followup 
 exploration led to the location of tin placer deposits near 
 Potato, Cape, Ear, and Brooks Mountains and later to the 
 discovery of lode-tin occurrences in the same areas. 
 
 The largest of the lode discoveries was the Lost River 
 Mine (map location 13 s ) near Brooks Mountain, which yielded 
 695,400 lb Sn metal during intermittent operation from 1901 
 to 1964 (4), as shown in table 1. The Lost River Mine and 
 minor production from lodes at Cape Mountain (map location 
 12) and possibly at Potato Mountain (map location 11) 
 account for all Alaskan lode tin production. 
 
 Most Alaskan tin production has come from placer 
 mines, and most of this production has been derived from 
 Buck and Grouse Creeks in the Potato Mountain area, and 
 Cape Creek in the Cape Mountain area, on the western 
 Seward Peninsula (4). (See table 1.) Since the commence- 
 
 2 Public Law 96-487, Dec. 2, 1980, title 10, section 1010. 
 
 3 Italic numbers in parentheses refer to items in the list of references 
 preceding the appendix. 
 
 4 Of the total 5,830,600 lb Sn production reported later in the text, 
 approximately 12,500 lb was derived using the 75-pct assumption. 
 
 ment of mining, the combined production of placer tin from 
 these two areas has totaled an estimated 4,292,000 lb. 
 
 Following the discovery of tin on the Seward Peninsula, 
 cassiterite was identified in concentrates from several gold 
 mining districts in interior Alaska. The most productive was 
 near Tofty (map location 36), in the Manley Hot Springs 
 district, where shipments of placer cassiterite concentrate 
 from bench gravels commenced in 1911 (11). Intermittent 
 production from this area through 1982 accounted for 
 approximately 400,000 lb Sn, 6 or approximately 7 pet of total 
 Alaskan tin production (table 1). Minor production of tin also 
 has been reported from the Ruby (map location 32), Circle 
 (map location 33), and Melozitna mining districts (map 
 locations 29-31) of interior Alaska. 
 
 Alaskan tin production is estimated to have totaled 
 approximately 5,830,600 lb to 1983. Tin production from 
 Cape Creek and Tofty was estimated to have totaled 
 approximately 198,000 lb in 1982 and 215,000 lb in 1983 
 (7-8, 72). The 1 983 output from these two areas was equal to 
 
 5 All references to map locations refer to locations shown in figure 1 (map in 
 pocket). In addition, both lode and placer occurrences are described in 
 appendix tables A-1 and A-2. 
 
 f Production estimates by Wayland (19) for the Tofty area are higher than 
 those by Thomas (11), which were used to calculate this figure. Wayland 
 estimates 352,600 lb Sn production through 1941, with little additional 
 production from 1941 through 1961, while Thomas estimates 282,000 lb Sn 
 production through 1956. 
 
Table 1.— Estimated production' of tin from lode and placer sources in Alaska 
 
 Source 
 
 (placer sources unless 
 
 otherwise specified) 
 
 Map 
 location 
 (fig. 1) 
 
 Period 
 
 Reported production, lb 
 (concentrate unless 
 otherwise specified) 
 
 References 
 
 SEWARD PENINSULA 
 
 Lode sources: 
 
 Lost River Mine area 
 
 Cape Mountain 
 
 Potato Mountain 
 
 Lost River Mine area 
 
 Do 
 
 Cape Mountain area 
 
 Do 
 Potato Mountain area 
 
 Oner Creek 
 
 Others 
 
 Total. Seward Peninsula 
 
 13 
 12 
 11 
 13 
 13 
 12 
 12 
 11 
 18 
 NAp 
 NAp 
 
 1901-64 
 1901-64 
 1902-53 
 1901-64 
 1964-65 
 1924-75 
 1979-82 
 1901-64 
 To 1 964 
 U 
 1901-82 
 
 695.400 
 
 12,000 
 
 2,000 
 
 187,296 
 
 ( 2 ) 
 
 1,537,000 
 
 = 765,250 
 
 2,204,600 
 
 ( 3 ) 
 
 < 1,000 
 
 s 5.400.000 
 
 (Sn metal) 
 (Sn metal) 
 (Sn metal) 
 (Sn metal) 
 
 (Sn metal) 
 (Sn metal) 
 (Sn metal) 
 
 (Sn metal) 
 (Sn metal) 
 
 4-5 
 
 5-8 
 
 4 
 
 9 
 
 10 
 
 NAp 
 
 TOFTY TIN BELT. MANLEY HOT SPRINGS DISTRICT 
 
 Cache Creek 
 
 Dalton Creek 
 
 L/6€u v c6K 
 
 Deep Creek tnbutanes 
 
 Idaho Gulch 
 
 Miller Gulch 
 
 Patterson Creek 
 
 Sullivan Creek 
 
 Tofty Gulch 
 
 Woodchopper Creek. . 
 Unspecified sources 
 Total. Tofty tin beir 1 
 
 36 
 
 NAp 
 
 1 906-56 
 
 ' 1966-82 
 1906-82 
 
 5,155 
 
 3,000 
 
 56,200 
 
 8,000 
 
 300 
 
 101,875 
 
 20,282 
 
 215,445 
 
 19,600 
 
 40,300 
 
 > 120,000 (Sn metal) 
 
 =402,100 (Sn metal) 
 
 10 
 
 12 
 NAp 
 
 RUBY DISTRICT 
 
 Big Creek and Cox Pup 
 
 Birch Creek 
 
 Glacier Creek 
 
 Greenstone Creek 
 
 Midnight Creek 
 
 Do 
 
 Short Creek 
 
 Straight 
 
 Fifth of July Creek 
 
 District total 
 
 32 
 
 NAp 
 
 To 1 962 
 1917-36 
 To 1962 
 1940-42 
 1917-18 
 1940-42 
 
 1918 
 1916-20 
 
 1922 
 1916-72 
 
 2,100 
 5,000 
 
 150 
 
 300 
 
 537 (Sn metal) 
 7,320 
 
 © 
 
 ( 3 ) 
 
 s300 (Sn metal) 
 =402,100 (Sn metal) 
 
 NAp Not Applicable U Unknown 
 
 1 Totals calculated assuming concentrates contained 75 pet Sn, except for Tofty tin belt concentrates (See footnote 4. 
 
 2 Several thousand pounds concentrate 
 
 ; Cassitente recovered, quantity unknown 
 
 4 Total calculation based on 60-pct reported average tin content of concentrate ( 10). 
 
 5 Few thousand pounds tin metal 
 
 13-14 
 
 14 
 13-14 
 
 14 
 
 13-14 
 
 13 
 
 14 
 
 NAp 
 
 CIRCLE DISTRICT 
 
 Deadwood and Boulder Creeks 
 
 33 
 
 To 1982 
 
 ( 3 ) 
 
 15-17 
 
 MELOZITNA DISTRICT 
 
 Mason Creek 
 
 30 
 
 29 
 
 29 
 
 NAp 
 
 1918 
 1938-43 
 
 1983 
 1918-83 
 
 2,000 
 
 =500 (Sn metal) 
 = 12,500 (Sn metal) 
 s14,500 (Sn metal) 
 
 14 
 
 Tozimoran Creek 
 
 18 
 
 Do 
 
 12 
 
 District total 
 
 NAp 
 
 STATEWIDE 
 
 Total for Alaska 
 
 NAp 
 
 1901-83 
 
 =5,830,600 (Sn metal) 
 
 NAp 
 
 about 0.2 pet of the 1983 U.S. consumption of primary tin 
 (88.000.000 lb) (20). 
 
 Published lode- and placer-tin reserve estimates are 
 summanzed in table 2. The largest reserves are at the Lost 
 River Mine (map location 13) on the western Seward 
 Peninsula, where indicated tin reserves are estimated at 
 85.000.000 lb in a zone of 0.15 pet Sn. 5,200,000 lb in a 
 deposit grading 0.26 pet Sn, and 1,600,000 lb in a deposit 
 grading 1.3 pet Sn. Inferred reserves at Lost River total 
 21 .000.000 lb of tin in four deposits ranging in grade from 0.4 
 to 1 .5 pet Sn. Approximately 20.000.000 lb Sn is also inferred 
 at the Coal Creek prospect in the Chulitna area (map location 
 49) and approximately 300.000 and 1,000,000 lb Sn are 
 reported to be indicated and inferred, respectively, at the 
 Boulder Creek prospect (map location 51) in the southern 
 Alaska Range' (24-25). Tofty (map location 36) is the only 
 placer area for which tin reserve figures have been 
 published. Approximately 3.900,000 lb Sn are indicated to 
 
 Table 2. — Tin reserves in Alaskan lode and placer deposits 
 (Published estimates) 
 
 Deposit name 
 
 Map 
 location 
 (fig 1) 
 
 Grade, 
 pet 
 
 Reserves, million lb 
 
 Measured 
 and indicated 
 
 Inferred 
 
 References 
 
 ' Reed (27-2ffi suggests substantially lower reserves at Boulder Creek 
 
 Lode deposits: , 
 
 
 
 
 
 
 Lost River Mine: 
 
 
 
 
 
 
 Cupola 
 
 
 0.151 
 
 85 
 
 NR 
 
 21 
 
 Cassitente Dike . . 
 
 
 1.5 
 
 NR 
 
 2.4 
 
 
 Do 
 
 13 
 
 1.3 
 
 1.6 
 
 NR 
 
 
 Do 
 
 '>1.0 
 
 NR 
 
 9 
 
 22 
 
 Do 
 
 
 .4 
 
 NR 
 
 5.2 
 
 Do 
 
 
 26 
 
 5.2 
 
 NR 
 
 
 Ida Bell Dike 
 
 
 .76 
 
 NR 
 
 4.4 
 
 
 Coal Creek 
 
 49 
 
 2 
 
 NR 
 
 20 ' 
 
 24 
 
 Boulder Creek ] 
 
 Do j 
 
 51 
 
 '2.41 
 2.41 
 
 NR 
 3 
 
 1.0 1 
 NR 
 
 25 
 
 Placer deposits: 
 
 
 
 
 
 
 Tofty 
 
 Do 
 
 Cape Creek 
 
 36 | 
 12 
 
 2 2.63 
 
 3.9 
 
 NR 
 
 11, 19, 26 
 
 2 0.58 
 
 NR 
 
 .7 
 
 26 
 
 2 2.6 
 
 NR 
 
 2.2 
 
 23 
 
 Total 
 
 
 
 960 
 
 44.9 
 
 NAp 
 
 
 
 
 
 NAp Not applicable. 
 
 'Gr< 
 
 ide uncertain 
 
 
 
 
 NR None reported. 
 
 2 Po 
 
 jnds per cubic yard. 
 
 
 
remain in 1 ,490,000 yd 3 of placer deposits, and approximate- 
 ly 733,000 lb Sn are inferred to remain in 1 ,259,000 yd 3 of 
 tailings gravels in the Tofty area 8 (11, 19, 26). 
 
 Additional reserves can be calculated from figures given 
 by Mulligan (23). Calculations suggest that 2,200,000 lb Sn 
 remain in 850,000 yd 3 gravel at Cape Creek in the Cape 
 Mountain area (map location 12). Also, based on minimal drill 
 data, in excess of 400,000 lb Sn is suggested to occur in the 
 combined placer deposits of Ear Mountain and Tozimoran 
 and Morelock Creeks (map locations 10, 29, and 31) ( 14, 29). 
 
 TANTALUM AND COLUMBIUM 
 
 Tantalum and columbium have no reported production in 
 Alaska, and no domestic production has been reported since 
 1959 (30-31). The only established reserves of columbium in 
 Alaska are at Tofty (map location 36), where approximately 
 135,000 lb of columbium oxide are inferred to be contained 
 within 2,660,000 yd 3 of placer and tailings gravels (32). 
 
 BUREAU OF MINES INVESTIGATIONS 
 
 The Bureau has published several reports concerning 
 tin, tantalum, or columbium in Alaska. Recent work includes 
 published and ongoing studies in the Sithylemenkat (33-34), 
 Porcupine Plateau (35-36), Tofty (32), and Circle Quadrangle 
 areas of interior Alaska ( 16, 37-38), the Mt. McKinley and Lake 
 Clark areas of the central and southern Alaska Range 
 (39-40), and the Selawik Hills area of northwestern Alaska 
 (41 ). Previous Bureau studies include extensive evaluation of 
 placer and lode deposits on the western Seward Peninsula 
 (23, 29, 42-47) as well as investigations in the Manley Hot 
 Springs district (11) and Melozitna district (18) in interior 
 Alaska. 
 
 TRENDS OF ALASKAN TIN OCCURRENCES 
 
 Alaskan lode and placer occurrences containing tin, 
 tantalum, and/or columbium are listed in the appendix, in 
 tables A-1 and A-2. Where available, abbreviated geologic, 
 geochemical, and production data are provided. Generally, 
 the criteria for inclusion of a tin occurrence or deposit in these 
 tables were (1 ) the presence of greater than trace amounts of 
 tin and (2) a possibility for large, although undefined, 
 volumes of material. However, a few tin occurrences that are 
 in unique geologic settings but do not necessarily meet these 
 criteria are also included for illustrative purposes. All 
 reported occurrences of tantalum and/or columbium are 
 included in these tables. The only commodities listed are 
 metals with potential economic importance. 
 
 On a broad scale, the tin-bearing lode and placer 
 occurrences of Alaska are part of a belt of tin mineralization 
 that extends along the western flank of North and South 
 America. As shown in figure 1 (map), the Alaskan portion of 
 the belt parallels major geologic provinces from the 
 Alaska-Yukon border across central Alaska to the Seward 
 Peninsula (48). Most of the tin occurrences within this belt 
 are spatially associated with nearby outcropping or subcrop- 
 ping biotite-bearing composite intrusions or felsic hypabyssal 
 stocks and dikes of Cretaceous or early Tertiary age. The 
 intrusions cut rocks of Precambrian (?) to Tertiary age and 
 probably resulted from anatectic melting of sialic crust during 
 a postorogenic period of magmatism (48-50). Thus, the 
 distribution of tin occurrences in Alaska may be an indirect 
 indication of areas underlain by continental crust. 
 
 On a smaller scale, the Alaskan tin belt is composed of 
 several stanniferous trends, each of which has particular 
 geologic characteristics and a variety of mineral deposit 
 types. In figure 1, these trends are referred to as "Alaska 
 Range," "Kuskokwim," "Yukon-Tanana," "Kokrine-Hodzana," 
 "Seward Peninsula," "Brooks Range," and "Northeast Alas- 
 ka." These mineral trends generally coincide with trends of 
 granitic intrusions and gravity lows (51-52) and generally 
 correlate with areas underlain by miogeosynclinal shelf or 
 
 8 Thomas ( 1 1) estimates 733,000 lb Sn in gravels in the Tofty area with a 
 total volume of 1 ,259,000 yd 3 , but does not give specific reserve locations. 
 Wayland (19), however, estimates 433,600 lb Sn in three specific tailings 
 areas, but does not give specific locations of in-place placer tin reserves. 
 
 slope deposits. Parallelism with the trend of some ophiolite 
 terranes and regional fault zones also suggests that the tin 
 trends are in part controlled by crustal suture or major 
 deep-seated fracture zones. Each of the regional trends is 
 discussed below. 
 
 ALASKA RANGE 
 
 The Alaska Range trend of tin occurrences (fig. 1) 
 extends south from near Healy to near Lake Clark, generally 
 subparallel to the McKinley strand of the Denali fault. The 
 trend includes the Chulitna-Yentna and parts of the Dall and 
 Kantishna mineral belts delineated by Hawley (39). Sulfide- 
 rich veins and skarns are locally enriched in tin, and 
 cassiterite is present in greisenized granite stocks along this 
 trend. A volcanogenic massive sulfide deposit in the 
 northeastern part of the trend contains local tin enrichments. 
 All the tin occurrences, except the massive sulfide, show 
 close affinities to approximately 56-m.y.-old McKinley Series 
 biotite-muscovite granites (49, 53) that generally intruded 
 Jurassic to Cretaceous age argillite south of the Denali fault, 
 but which also cut mixed volcano-sedimentary assemblages 
 west of Cantwell and north of the Denali fault. 
 
 YUKON-TANANA 
 
 The Yukon-Tanana trend of tin occurrences follows the 
 Yukon-Tanana Upland province in interior Alaska and 
 generally parallels the Tintina fault to the north, which is 
 interpreted as an extension of the Rocky Mountain trench in 
 Canada (54). Virtually every placer gold district in the 
 province contains at least traces of cassiterite, but most of 
 the tin occurrences are confined to the area between Circle 
 Hot Springs and the White Mountains, north and northeast of 
 Fairbanks (fig. 1 ). Tin occurrences in this area are associated 
 with late Cretaceous-early Tertiary age biotite granite 
 composite intrusions that have intruded the sedimentary 
 facies boundary between late Precambrian-early Paleozoic 
 miogeosynclinal shelf and slope deposits, a boundary 
 represented by the transition between rocks of the Wicker- 
 sham and White Mountain terranes to the northwest and the 
 Yukon-Tanana terrane to the southeast (54-55). This 
 boundary may be the fault-offset analog of the MacKenzie 
 Mountain-Selwyn Basin transition in Canada (54, 56-57), 
 which coincides with a belt of Canadian tin occurrences (58). 
 The Yukon-Tanana tin trend, therefore, may be an extension 
 of the Canadian tin belt. 
 
 The placer tin deposits of the Tofty area in the Manley Hot 
 Springs district have similarities to and may be transitional 
 between tin occurrences of the Yukon-Tanana and Kuskok- 
 wim tin trends. At Tofty, although the tin source is unknown, 
 both a biotite granite, similar to those of the Yukon-Tanana 
 trend, and a monzonite stock, similar to those of the 
 Kuskoskwim trend, are exposed (19). Like the placer 
 deposits of the Yukon-Tanana trend, the tin at Tofty occurs 
 as an accesory to gold; however, like many of the Kuskokwim 
 
trend deposits, the Tofty deposits are enriched with 
 columbium. Lastly, both the Tofty and the Kuskokwim trend 
 deposits are underlain by clastic sedimentary rocks of 
 Jurassic-Cretaceous or Cretaceous age (19). 
 
 KUSKOKWIM 
 
 The Kuskokwim trend of tin occurrences extends 
 subparallel to the Iditarod-Nixon Fork fault in west-central 
 Alaska, from near Aniak northeastward to near Manley Hot 
 Springs (fig. 1). Tin occurrences are associated with a varied 
 assemblage of hypabyssal and plutonic intrusive rocks of 
 monzonitic to granitic or rhyolitic composition. These rocks 
 are of late Cretaceous to early Tertiary age and generally 
 intrude sedimentary rocks of the Cretaceous Kuskokwim 
 group. The presence of hypabyssal stocks and dikes, locally 
 widespread thermal alternation and tourmalinization, and 
 tin-silver-copper-rich veins (59) (table A-1) suggests that 
 many of the occurrences in this area occur within shallow, 
 possibly subvolcanic settings. 
 
 KOKRINE-HODZANA 
 
 The Kokhne-Hodzana tin trend lies northwest of the 
 Kuskokwim and Yukon-Tanana trends, stretching from near 
 Tanana northeastward across interior Alaska subparallel with 
 the Kaltag fault system (fig. 1). Tin occurrences along the 
 trend are associated with a 90- to 110-m.y.-old suite of 
 plutons that has intruded lower to middle Paleozoic (?) age 
 pelitic metasedimentary rocks of the Ruby "geanticline" (50, 
 60-62). These intrusions are in part separated from younger 
 ones in the Yukon-Tanana and Kuskokwim trends by the 
 southwest-trending Kaltag fault. The Ruby district (map 
 location 32) may be an extension of the Kokrine-Hodzana 
 trend that has been offset to the southwest by the Kaltag 
 fault. 
 
 SEWARD PENINSULA 
 
 The Seward Peninsula tin trend largely consists of a 
 group of deposits that extends across the Seward Peninsula 
 from Cape Mountain eastward to Kougarok Mountain and 
 beyond (fig. 1). The deposits are characterized by tin- 
 fluorine-beryllium zoned replacement lodes and veins formed 
 by metasomatism of upper Precambrian (?) to middle 
 Paleozoic age pelitic and carbonate rocks adjacent to 70- to 
 80-m.y.-old biotite-bearing granites (table A-1). 
 
 Additional tin occurrences, associated with the 80-m.y.- 
 old Darby pluton, have been identified in the Darby Mountain 
 area of the southeastern Seward Peninsula (63). Tin 
 occurrences in this area are probably unrelated geologically 
 to the other Seward Peninsula occurrences. 
 
 NORTHEAST ALASKA AND BROOKS RANGE 
 
 Unlike other tin occurrences in Alaska, tin occurrences 
 of the northeast Alaska trend (fig. 1) are associated with 
 probable middle Paleozoic age (350 m.y.) intrusions. These 
 intrusions have invaded Precambrian (?) to lower Paleozoic 
 age miogeosynclinal metasedimentary rocks of the Porcu- 
 pine Plateau (36). The northeast Alaska trend may extend 
 into the Brooks Range trend (fig. 1), where recent 
 interpretations (64) suggest intrusions of similar mid- 
 Paleozoic age; however, detailed data are lacking. 
 
 OTHER AREAS WITH TIN OCCURRENCES 
 
 Several tin occurrences in southern and southeast 
 Alaska are not associated with known tin trends. (See figure 
 1 and "Other Occurrences" portion of table A-1 .) In southern 
 Alaska, near Cordova, tin is associated with two breccia or 
 altered zones in greenstone and metasedimentary rocks. In 
 southeast Alaska, tin occurs as a minor element in several 
 base-metal vein or replacement deposits. 
 
 TIN LODE OCCURRENCES 
 
 Lode occurrences of tin in Alaska generally are of five 
 main types: greisen. vein, skarn. pegmatite, and volcanogenic 
 massive sulfide. Tin also occurs in a fumarole 
 deposit at the Valley of Ten Thousand Smokes (65) (map 
 location 54). Greisen and vein occurrences far outnumber 
 the other types of occurrences; however, in terms of 
 production, the skarn type (at the Lost River Mine, map 
 location 13) historically has been most important. The 
 following sections summarize the tin lode occurrence data 
 presented in table A-1. 
 
 GREISEN 
 
 Greisen occurrences are centered about or confined to 
 biotite granite or felsic hypabyssal stocks. These occurrences 
 are typified by lithophile element-rich alteration 
 minerals that accompany disseminated and stockwork or 
 sheeted vein mineralization within or near the cupola of an 
 intrusion. Important examples include the Lost River Mine 
 (map location 13) and the recent discovery at Coal Creek in 
 the Chulitna area (map location 49). Other unevaluated 
 occurrences include greisen mineralization at Lime Peak 
 (map location 34). Ketchem Dome in the Circle mining district 
 (map location 33). Sithylemenkat (map location 25). Kougar- 
 ok Mountain (map location 16). Rapid River (map location 3). 
 Esotuk and McCall Glaciers (map location 1), and Ohio 
 Creek in the Chulitna area (map location 49). 
 
 VEIN 
 
 Vein mineralization most commonly occurs distal from 
 the intrusion. The veins cut regionally or contact metamor- 
 phosed rocks and typically can be traced for hundreds of feet. 
 Mineralization is usually polymetallic and silver- and sulfur- 
 rich; and it is usually enclosed within a shear or breccia zone 
 by a relatively restricted quartz-rich alteration selvage. Unlike 
 the stockwork and sheeted veins associated with greisen 
 mineralization, these veins are generally more continuous, 
 more enriched in silver and sulfur, and usually are relatively 
 isolated. 
 
 Examples of Alaskan vein occurrences include the 
 Boulder Creek prospect (map location 51), which is 
 described as a cluster of narrow, open-space-filling fractures 
 localized along a 1- to 6-m-wide fracture zone within 
 metasedimentary rocks overlying a granite cusp (28). Lesser 
 known occurrences that may prove to be important include 
 those at Cosna (map location 37), Quartz Creek (map 
 location 28), the Omilak and Foster prospects (map location 
 21), and new discoveries in the western Medfra Quadrangle 
 (Win and Won prospects, map locations 38-39). 
 
 SKARN 
 
 Tin-bearing skarn deposits occur as tabular or vein like 
 zones within carbonate rocks adjacent to biotite granites or 
 
felsic dikes. Commonly, like the adjacent greisenized granite, 
 these deposits contain lithophile element-rich alteration 
 minerals and potentially economic concentrations of fluorine, 
 beryllium, and tungsten. Well-known metasomatic- 
 replacement deposits are the Lost River Mine (map location 
 13) and Cape Mountain lode (map location 12). Minor 
 tin-bearing skarn occurrences also occur at Mountain Creek 
 (Rapid and Porcupine Rivers area, map location 3) in 
 northeastern Alaska and several prospects in the Brooks 
 Range (Kaluich and two unnamed occurrences, map 
 locations 4-6). 
 
 PEGMATITE 
 
 Tin-bearing pegmatites are poorly documented in 
 
 Alaska. Pegmatites carrying tin values have been found at 
 the Ketchem Dome prospect in the Circle district (map 
 location 33), at the Janiksela occurrence in the Fairbanks 
 district (map location 35), and at the Kiana occurrence (map 
 location 7) in the Brooks Range. 
 
 VOLCANOGENIC 
 MASSIVE SULFIDE 
 
 Tin-bearing volcanogenic massive sulfide has been 
 discovered at the Sheep Creek prospect (map location 47) in 
 the central Alaska Range (66). One 350-ft drill intersection 
 there averages 0.035 pet Sn. A narrower, 8-ft zone contains 
 1 .2 pet Sn. The deposit is hosted within a siliceous exhalite 
 (?) horizon and overlain by graphitic schists. 
 
 TIN PLACER OCCURRENCES 
 
 Like most world tin production, the bulk of Alaskan tin 
 production comes from placer deposits. Cassiterite is a 
 common accessory mineral in placer concentrates through- 
 out much of Alaska. Approximately 90 pet of Alaskan placer 
 production has been from the western Seward Peninsula. 
 The remainder was recovered with gold from placer mines in 
 interior Alaska (tables 1 and A-2). Placer tin occurrences of 
 unknown grade occur in the Sithylemenkat River area (map 
 location 25) of interior Alaska and in the Rapid and Porcupine 
 Rivers area (map location 3) of northeastern Alaska (33-35). 
 Anomalously large amounts of tin also have been found in 
 numerous creeks in other areas of the Seward Peninsula, in 
 interior Alaska, and in the Yentna district (map location 52), 
 southeast of the Alaska Range (67). 
 
 Tin occurs as cassiterite, along with various other 
 high-specific-gravity minerals such as gold, scheelite, wolfra- 
 mite, magnetite, ilmenite, rutile, garnet, monazite, allanite, 
 zircon, columbite, and cinnabar, in the heavy-mineral fraction 
 of sands and gravels. Many of the tin placer deposits listed in 
 table A-2 contain associated gold, tungsten, rare-earth 
 elements, tantalum, and/or columbium, which must be 
 considered in evaluating the placer's economic viability. 
 
 Cassiterite occurs in placers both as individual grains, 
 which range from extremely fine to sand and pebble size, and 
 as a constituent of larger cobbles. Grains of all sizes may 
 vary from extremely angular to well-rounded. Cassiterite- 
 
 bearing cobbles, sometimes termed "tinstone," often were 
 not recovered in the past because their size necessitated 
 hand sorting. 
 
 Cassiterite is present in bench, stream, river, and beach 
 placers. Small, but anomalous amounts of cassiterite have 
 also been detected in bottom sediment samples collected 
 offshore in the Bering Strait-Cape Prince of Wales area (68), 
 suggesting a potential for marine placers. 
 
 Insufficient data preclude determining average grade 
 and yardage figures for tin-bearing placer deposits in 
 Alaska as a whole. Generally, however, creeks that have 
 yielded tin contain approximately 1 lb/yd 3 cassiterite or more, 
 60 pet or more tin in concentrates, and 10,000 yd 3 or more of 
 placer material (table A-2). However, the major tin-producing 
 creeks, including Buck, Grouse, and Cape Creeks in the 
 Potato and Cape Mountain areas (map locations 11-12) on 
 the Seward Peninsula and many of the creeks in the Tofty 
 area (map location 36), probably contain material grading 
 greater than 2.0 lb/yd 3 Sn. On Buck and Grouse Creeks, 
 2,204,600 lb Sn was produced from 560,000 yd 3 of gravels 
 between 1901 and 1964 (42-43). In the Tofty area, 
 approximately 1,490,000 yd 3 of reserve placer gravels is 
 indicated to contain 2.6 lb/yd 3 Sn (19). A published drill report 
 on Cape Creek indicates approximately 850,000 yd 3 of 
 gravels with an average grade of 2.6 lb/yd 3 Sn (23). 
 
 REGIONAL FEATURES OF ALASKAN 
 TANTALUM AND COLUMBIUM OCCURRENCES 
 
 Worldwide, deposits of columbium and tantalum occur in 
 carbonatite-alkaline syenite complexes, pegmatites, or alkali- 
 rich granites (69). Until 1961 , the major source of columbium 
 consumed in the United States was columbite in placers 
 derived from the erosion of peralkaline granites and 
 pegmatites in Nigeria; however, the major source today is 
 pyrochlore obtained from carbonatites in Canada and Bolivia. 
 Pegmatites are the dominant source of tantalum in the world. 
 
 In Alaska, most of the columbium and tantalum 
 occurrences are found within the same trends as the tin 
 occurrences. Columbium and tantalum are reported in the 
 Northeast Alaska, Kokrine-Hodzana, Yukon-Tanana, and 
 Kuskokwim tin trends. Where they are associated with tin, 
 
 tantalum and columbium occur within minor accessory 
 minerals either within the tin-bearing granite or within a 
 related, more alkaline phase of the granite. Columbium and 
 tantalum may also occur in trace amounts in cassiterite or 
 may be associated with cassiterite in pegmatites. 
 
 In other areas of Alaska, for example southeastern 
 Alaska and the western Yukon-Koyukuk basin, tantalum and 
 columbium occurrences are not associated with tin and do 
 not occur within tin trends. In these areas, columbium and 
 tantalum are associated with peralkaline intrusions or 
 pegmatites. Other alkaline intrusive complexes in southeast- 
 ern, western, and other areas of Alaska may also contain 
 columbium and tantalum. 
 
 TANTALUM AND COLUMBIUM LODE OCCURRENCES 
 
 Tantalum and columbium reported in Alaskan lode 
 prospects occur in trace amounts associated with uranifer- 
 
 ous alkaline complexes, in pegmatites, in tungsten-bearing 
 molybdenum porphyries or in tin-bearing greisens (table 
 
A-1). Tantalum and columbium in these occurrences may be 
 recoverable as byproduct commodities. 
 
 At Bokan Mountain (map location 61), columbium occurs 
 in grades of 0.01 to 1.0 pet and is associated with uranium 
 and thorium minerals within a peralkaline granite (70). 
 Mineralization in the Bokan Mountain area consists of 
 disseminated uranium-thorium minerals in granite, aplite, 
 and pegmatite: hydrothermally deposited uranium-thorium 
 minerals in or near fractures; and uranium-thorium minerals 
 in interstices of quartzite (70-71). Both columbite and 
 pyrochlore have been identified. 
 
 In the Selawik Hills (map location 9). columbium is found 
 in uraniferous altered zones within an alkaline complex (41). 
 A columbium-uranium-titanium-bearing mineral has been 
 identified in this area. This same or a similar mineral has 
 been reported in the placers of Vulcan and Clear Creeks 
 (map location 22). where it is apparently derived from the 
 Darby Mountain igneous complex in the eastern Seward 
 Peninsula. 
 
 Columbium occurs in a pegmatite at the Edelweiss 
 prospect (map location 59) in southeastern Alaska, and 
 tantalum and columbium are reported in a pegmatite at the 
 Kiana occurrence (map location 7) in the western Brooks 
 Range (72-73). At the Kiana occurrence, columbite and 
 tantalite are reported to occur with cassiterite. Both localities 
 remain unevaluated. 
 
 An open-ended 4,000-ft-long by 200- to 2,000-ft-wide 
 columbium soil geochemical anomaly with values of 0.006 to 
 0.018 pet Cb corresponds to molybdenum-tungsten miner- 
 alization associated with an altered porphyry at Bear 
 Mountain (map location 2) in northeastern Alaska (74). 
 Pyrochlore was identified in a pan concentrate sample 
 collected nearby. 
 
 At the Kougarok prospect (map location 16) on the 
 Seward Peninsula, tantalum and columbium values in the 
 0.01- to 0.03-pct range are associated with parts of the 
 tin-mineralized greisen. The tantalum- and columbium- 
 bearing minerals have not been identified. 
 
 COLUMBIUM AND TANTALUM PLACER OCCURRENCES 
 
 Columbium and, less commonly, tantalum occur in 
 anomalously large amounts in many placer and heavy- 
 mineral concentrate samples in Alaska. They are not known 
 to occur in concentrations that would justify mining them as a 
 primary commodity, but some of the higher concentrations 
 may be recoverable as byproducts of tin or gold mining. The 
 only occurrences that have been studied in any detail are at 
 Tofty (map location 36) in the Manley Hot Springs district of 
 interior Alaska. (See table A-2 for detailed data on placer 
 occurrences.) 
 
 At Tofty. columbium occurs within columbite and 
 possibly aeschynite [Ce, Ca, Fe. Th)(Ti, Cb) ? (0, OH) 6 ] (32). 
 The columbium occurs in grades averaging 0.05 lb/yd 3 
 columbium oxide and is associated with tin and gold in the 
 placer deposits; however, the columbium and tin may have 
 different sources. The sources of the columbium and tin are 
 unknown. 
 
 Also in interior Alaska, anomalously large amounts of 
 tantalum and columbium occur in the Sithylemenkat area 
 (map location 25). where placer concentrate samples 
 containing detectable columbium and tantalum average 0.26 
 and 0.062 pet. respectively (34). Several other placer 
 deposits in interior Alaska, including those of the Ruby, 
 Circle, and Fairbanks districts (map locations 32-33 and 35), 
 also contain anomalously large amounts of columbium (75). 
 
 In northeastern Alaska, values of 0.05 to 0.1 pet Cb have 
 been found in association with tin, tungsten, and rare-earth 
 
 metals in sluice-box concentrate samples from the Rapid 
 River drainage (map location 3) (35). At the Bear Mountain 
 prospect (map location 2), concentrate from a bulk sample of 
 alluvial gravel collected 2 mi downstream from the mineral- 
 ized zone contained 0.15 pet Cb and 3 pet W (74). 
 
 On the Seward Peninsula, columbium is reported in 
 tin-bearing gravels of Tuttle Creek (Ear Mountain area, map 
 location 10), Boulder and Cape Creeks (Cape Mountain 
 area, map location 12), and Cassiterite Creek (Lost River 
 Mine area, map location 13) (28, 42, 75). Reported values 
 range from 0.001 to 0.10 pet Cb in spectrographic analyses 
 of churn-drill concentrate samples. Columbium values 
 associated with uranium occur in the Clear and Vulcan 
 Creeks area (map location 22) of the Darby Mountains on the 
 southeastern Seward Peninsula, where a range of 0.03 to 
 0.18 lb/yd 3 Cb and an average of 1 pet Cb in concentrates (19 
 samples) was reported (44). Creeks draining the Kougarok 
 Mountain (map location 16) and Granite Mountain (map 
 location 23) areas on the central and eastern Seward 
 Peninsula, respectively, are also reported to contain anoma- 
 lously large concentrations of columbium (75). 
 
 In the Kuskokwim Mountains, anomalously large 
 amounts of columbium are reported in stream gravels from 
 the Vinasale Mountain (map location 42) and Marvel Creek 
 (map location 46) areas (75). These occurrences have not 
 been evaluated. 
 
 SUMMARY 
 
 Data compiled from published and unpublished sources 
 indicate that Alaska contains a significant portion of the 
 United States reserves of tin. The State also contains minor 
 reserves of columbium and occurrences of tantalum. All 
 three of these critical and strategic metals could be obtained 
 from Alaska during a period of national shortage. 
 
 An estimated 5.830.600 lb of tin has been produced, and 
 an estimated additional 140,900.000 lb has been measured, 
 indicated, or inferred to occur within Alaskan lode and placer 
 deposits Alaskan tin reserves represented about 150 pet of 
 U.S. consumption of primary tin in 1983. whereas the State's 
 current production of about 200,000 lb yr represents about 
 0.2 pet of domestic consumption. Western Seward Peninsula 
 placer mines have yielded most of the tin produced; however, 
 it is that area s lode deposits that contain most of the State's 
 reserves. 
 
 On a broad scale, Alaskan tin lode and placer 
 occurrences are part of a belt of tin mineralization that 
 extends along the western flank of North and South America. 
 On a smaller scale, however, the Alaskan portion of the "tin 
 belt" comprises several stanniferous trends, each with 
 particular geologic attributes and a variety of lode and placer 
 occurrence types. Five main tin lode types are represented: 
 greiaen, vein, skarn, pegmatite, and volcanogenic massive 
 sulfide. Although greisen and vein occurrences are the most 
 abundant in the State, skarn deposits have historically been 
 the most valuable. Bench, stream, river, and beach placers 
 are also represented within the Alaskan tin trends. Most of 
 these placers are located on the Seward Peninsula or in 
 interior Alaska; however, occurrences are also reported in 
 northern and south-central Alaska. 
 
 Alaska has not produced columbium or tantalum and 
 
has no tantalum reserves. Approximately 135,000 lb of 
 niobium oxide is inferred within the tin- and gold-bearing 
 placers of Tofty, in interior Alaska. Anomalously high 
 columbium concentrations are also reported in association 
 with uraniferous alkaline complexes in southeastern and 
 western Alaska, with a molybdenum-tungsten-mineralized 
 porphyry in northeastern Alaska, and in tin- and/or gold- 
 bearing placers on the Seward Peninsula and in interior 
 
 Alaska. Anomalously high tantalum and columbium values 
 are reported in association with tin-bearing greisen on the 
 Seward Peninsula, with pegmatites in southeastern and 
 northern Alaska, and in a placer in interior Alaska. Where the 
 columbium and tantalum concentrations are relatively high, 
 these minerals may be recoverable as byproducts of tin or 
 gold mining. 
 
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 64. Dillion, J. T.. G. H. Pessel. J. H. Chen, and N. C. Veach. 
 Tectonic and Economic Significance of Late Devonian and Late 
 Proterozoic U-Pb Zircon Ages From the Brooks Range, Alaska. AK 
 Div. Geol. and Geophys. Surv. Geol. Rep. 61. 1979. dd. 36-41. 
 
 65. Lovenng. T. S. Halogen and Acid Alteration at Fumarole No. 
 1. Valley of Ten Thousand Smokes, Alaska. Geol. Soc. America 
 Bull., v. 68. 1957. pp. 1585-1603. 
 
 66. Hammit. J. (Bear Creek Min. Co.). Private communication. 
 1984: available upon request from J. D. Warner, BuMines, 
 Fairbanks. AK. 
 
 67 Caps. S. R. The Yenta District. Alaska. U.S. Geol. Surv. Bull. 
 534. 1913. 75 pp. 
 
 68. Larson. B. R.. C H. Nelson. C. Heropoulos, and J. J. 
 Patry Distribution of Trace Elements in Bottom Sediment of the 
 Northern Bering Sea. U.S. Geol. Surv. OF 80-399. 1980, 40 pp. 
 
 69. Dawson. K. R. Niobium (Columbium) and Tantalum in 
 Canada. Geol. Surv Can. Econ. Geol. Rep. 29. 1974. 157 pp. 
 
 70. MacKevett. E. M . Jr. Geology and Ore Deposits of the Bokan 
 Mountain Uranium-Thorium Area. U.S. Geol. Surv. Bull. 1 154, 1963, 
 82 pp 
 
 71. Staatz. M. H. I and L Uranium and Thorium Vein Systems. 
 Bokan Mountain. Southeastern Alaska. Econ. Geol. v. 73. No. 4. 
 1978. pp. 512- 524 
 
 72 Anderson. E. Mineral Occurrences in Northwestern Alaska. 
 AK Dept Mines Pamphlet 5-R. 1944, 37 pp 
 
 73 Lathram. E. H.. J. S Pomeroy. H S Berg, and R. A Loney. 
 Reconnaissance Geology of Admiralty Island, Alaska. U.S. Geol. 
 Surv Bull. 1181-R. 1965. 48 pp. 
 
 74 Barker. J C . and R. C. Swambank. A Tungsten-Rich 
 Molybdenum Porphyry Occurrence at Bear Mountain, Northeastern 
 Alaska BuMines OFR 85-5. 1984. 64 pp. 
 
 75. Samsbury. C L.. and B I Thomas Location of Anomalous 
 Concentrations of Metals in Alaskan Placer Concentrate Samples. 
 (Maps j BuMines OFR 56-76. 1975 
 
 76. Grybeck. D Known Mineral Deposits of the Brooks Range, 
 Alaska. US. Geol Surv. OF 77-166-C. 1977. 45 pp. 
 
 77 Brosge . W. P. and H N Reiser. Preliminary Geologic and 
 Mineral Resource Maps (Excluding Petroleum). Arctic National 
 Wildlife Range. Alaska US Geol. Surv. Map of 76-539, 1976. 
 
 78 Garland. R. E . G E Eakins. T C Trible. and W. W. 
 
 McClintock. Geochemical Analysis of Rock and Stream Sediment 
 Samples, Survey Pass A-4, A-5, A-6, B-5, and B-6 Quadrangles, 
 Alaska. AK Div. Geol. and Geophys. Surv. Open File Rep. 67, 1975, 
 2 pp. 
 
 79. Dillion, W. S., M. A. Moorman, and L. Lueck. Geochemical 
 Reconnaissance of the Southwest Wiseman Quadrangle, Summary 
 of Data on Rock Samples. AK Div. Geol. and Geophys. Surv. Open 
 File Rep. 133B. 1981, pp. 67-68, 80, 96. 
 
 80. U.S. Bureau of Mines. A Mineral Appraisal of the Areas 
 Traversed by the Salmon and Noatak Rivers in the Western Brooks 
 Range: A Summary Report. BuMines OFR 50-79, 1979, 16 pp. 
 
 81. Borg, H. C, and E. H. Cobb. Metalliferous Lode Deposits of 
 Alaska. U.S. Geol. Surv. Bull. 1246, 1967, 254 pp. 
 
 82. Lu, C. J., L. E. Heiner, and D. P. Harris. Known and Potential 
 Ore Reserves, Seward Peninsula, Alaska. Univ. AK, Fairbanks, AK, 
 Miner. Ind. Res. Lab. Rep. 18, 1968, 105 pp. 
 
 83. Sainsbury, C. L., and Hamilton, J. C. Mineralized Veins at 
 Black Mountain, Western Seward Peninsula, Alaska. U.S. Geol. 
 Surv. Prof. Paper 575-B, 1967, pp. B21-B25. 
 
 84. Sainsbury, C. L., R. Kachadoohan, T. E. Smith, and W. C. 
 Todd. Cassiterite in Gold Placers at Humboldt Creek Serpentine- 
 Kougarok Area, Seward Peninsula, Alaska. U.S. Geol. Surv. Circ. 
 565, 1968, 7 pp. 
 
 85. Puchner, C. C. (Anaconda Miner. Co.). Private communica- 
 tion, 1984; available from J. D. Warner, BuMines, Fairbanks, AK. 
 
 86. Mulligan, J. J. Lead-Silver Deposits in the Omilak Area, 
 Seward Peninsula, Alaska. BuMines Rl 6018, 1962, 44 pp. 
 
 87. Miller, T. P., and R. L. Elliot. Metalliferous Deposits Near 
 Granite Mountain, Eastern Seward Peninsula, Alaska. U.S. Geol. 
 Surv. Circ. 614, 1969, 19 pp. 
 
 88. Freeman, L. (Resource Associates of Alaska, Inc.). Private 
 communication, 1983; available upon request from J. D. Warner, 
 BuMines, Fairbanks, AK. 
 
 89. Barker, J. C. (BuMines). Private communication (to J. J. 
 Mulligan), 1983; available upon request from J. D. Warner, BuMines, 
 Fairbanks. AK. 
 
 90. Thomas, B. I. (BuMines). Private communication (to R. V. 
 Berryhill), 1964; available upon request from J. D. Warner, BuMines, 
 Fairbanks, AK. 
 
 91. Chapman, R. M. Geochemical Anomalies in Bedrock, West 
 Half of Kantishna River Quadrangle. Ch. in Accomplishments During 
 1976. U.S. Geol. Surv. Circ. 751 -B, 1976, pp. B35-B36. 
 
 92. Pilcher, S. H. (Duval Corp.). Private communication, 1984; 
 available upon request from J. D. Warner, BuMines, Fairbanks, AK. 
 
 93. Bundtzen, T. K., and G. M. Laird. Geologic Map of the Iditarod 
 D-2 and Eastern D-3 Quadrangles, Alaska. AK Div. Geol. and 
 Geophys. Surv. Geol. Rep. 72, 1982. 
 
 94. Cady, W. M., R. E. Wallace, J. M. Hoare, and E. S. Webber. 
 The Central Kuskokwim Region, Alaska. U.S. Geol. Surv. Prof. 
 Paper 268, 1955, 132 pp. 
 
 95. West, W. S. Reconnaissance for Radioactive Deposits in the 
 Lower Yukon-Kuskokwim Region, Alaska, 1952. U.S. Geol. Surv. 
 Circ. 328, 1954, 10 pp. 
 
 96. Maddren, A. G. Gold Placers of the Lower Kuskokwim, With a 
 Note on Copper in the Russian Mountains. U.S. Geol. Survey Bull. 
 622, 1915, pp. 292-360. 
 
 97. Bundtzen, T. K. Geology and Mineral Deposits of the 
 Kantishna Hills, Mt. McKinley Quadrangle, Alaska. M.S. Thesis, 
 Univ. AK, Fairbanks, AK, 1981, 238 pp. 
 
 98. Hawley, C. C, and A. L. Clark. Geology and Mineral Deposits 
 of the Chulitna-Yentna Mineral Belt, Alaska. U.S. Geol. Surv. Prof. 
 Paper 758-A, 1973, 10 pp. 
 
 99. Geology and Mineral Deposits of the 
 
 Upper Chulitna District, Alaska. U.S. Geol. Surv. Prof. Paper 758-B, 
 1974, 47 pp. 
 
 100 Cobb, E. H. Summary of References to Mineral Occurrences 
 (Other Than Mineral Fuels and Construction Materials) in the Healy 
 Quadrangle, Alaska. U.S. Geol. Surv. OF 78-1062, 1978, 112 
 
 PP- 
 
 101. Reed, B L. Disseminated Tin Occurrences Near Coal Creek, 
 Talkeetna Mountain D-6 Quadrangle, Alaska. U.S. Geol. Surv. OF 
 78-77, 1978, 8 pp. 
 
 102. Cobb E. H., and B. L. Reed. Summaries of Data on and Lists 
 of References to Metallic and Selected Nonmetallic Mineral Deposits 
 in the Talkeetna Quadrangle, Alaska. U.S. Geol. Surv. OF 80-884, 
 1980. 106 pp. 
 
 103 Maloney, R. P., and B. I. Thomas. Investigation of the 
 Purkeypile Prospects, Kuskokwim River Basin, Alaska. BuMines 
 OFR 5-66, 1966, 12 pp. 
 
 104. Fechner, S. (BuMines). Private communication, 1983; 
 available upon request from J. D. Warner, BuMines, Fairbanks, AK. 
 
 105. Brew, D. A., B. R. Johnson, D. Grybeck, A. Griscom, D. F. 
 Barnes, A. L. Kimball, J. C. Still, and J. L. Rataj. Mineral Resources 
 
10 
 
 of the Glacier Bay National Monument Wilderness Study Area, 
 Alaska. U.S. Geol. Surv. OF 78-494, 1978, 656 pp. 
 
 106. Karl, S. M. Preliminary Map and Tables Describing 
 Metalliferous and Selected Nonmetalliferous Mineral Deposits in the 
 Petersburg and Eastern Port Alexander Quadrangles, Alaska. U.S. 
 Geol. Surv. OF 80-793, 1980. 
 
 107. Eakins, G. R. Uranium Investigations in Southeastern 
 Alaska. AK Div. Geol. and Geophys. Surv., Geol. Rep. 44, 1975, 62 
 pp. 
 
 1 08. Cobb, E. H. Summary of References to Mineral Occurrences 
 (Other Than Mineral Fuels and Construction Materials) in the 
 Beaver, Bettles, and Medfra Quadrangles. U.S. Geol. Surv. OF 
 78-94, 1978, 55 pp. 
 
 109. Placer Deposits of Alaska. U.S. Geol. 
 
 Surv. Bull. 1379, 1973, 213 pp. 
 
 110. Heide, H. E., and R. S. Sanford. Churn Drilling at Cape 
 Mountain Tin Placer Deposits, Seward Peninsula, Alaska. BuMines 
 Rl 4345, 1948, 14 pp. 
 
 111. Sainsbury, C. L, R. Kachadoorian, T. Hudson, T. E. Smith, 
 T. R. Richards, and W. E. Todd. Reconnaissance Geologic Maps 
 
 and Sample Data, Teller A-1, A-2, A-3, B-1, B-2, B-3, C-1, and 
 Bendeleben A-6, B-6, C-6, D-5, D-6 Quadrangles, Seward 
 Peninsula, Alaska. U.S. Geol. Surv. OF 377, 1969, 49 pp. 
 
 112. Cobb, E. H. Summaries of Data on and Lists of References 
 to Metallic and Selected Nonmetallic Mineral Occurrences in the 
 Bendeleben Quadrangle, Alaska. Supplement »o OF 75-429, Part 
 A— Summaries of Data to Jan. 1, 1980. U.S. Geol. Surv. OF 
 81-0363-A, 1981, 26 pp. 
 
 113. Thomas, B. I., and W. S. Wright. Investigations of Morelock 
 Creek Tin Placer Deposits, Fort Gibbon District, Alaska. BuMines Rl 
 4322, 1948, 8 pp. 
 
 114. Mulligan, J. (BuMines). Private communication, 1984; 
 available from J. D. Warner, BuMines, Fairbanks, AK. 
 
 115. White, G. E., and G. E. Tolbert. Miller House— Circle Hot 
 Springs Area. Ch. in Reconnaissance for Radioactive Deposits in 
 East Central Alaska, 1949. U.S. Geol. Surv. Circ. 335, 1954, 4-6 pp. 
 
 116. Maloney, R. P. Investigation of Mercury-Antimony Deposits 
 Near Flat, Yukon River Region, Alaska. BuMines Rl 5991, 1962, 44 
 pp. 
 
11 
 
 APPENDIX.— LISTINGS OF LODE AND PLACER OCCURRENCES OF TIN, TANTALUM, 
 
 AND COLUMBIUM IN ALASKA 
 
 Tables A-1 and A-2 list Alaskan lode and placer 
 occurrences containing tin. tantalum, and or columbium. 
 Where available, abbreviated geologic, geochemical. and 
 production data are provided. Generally, the criteria for 
 inclusion of a tin occurrence or deposit in these tables were 
 (1) the presence of greater than trace amounts of tin and (2) 
 a possibility for large, although undefined, volumes of 
 
 material. However, a tew tin occurrences that are in unique 
 geologic settings but do not necessarily meet these criteria 
 are also included for illustrative purposes. All reported 
 occurrences of tantalum and/or columbium are included in 
 these tables. The only commodities listed are metals with 
 potential economic importance. 
 
 Table A-1. — Lode occurrences 
 
 (For placer occurrences in the vicinity of a listed location, see listings in table A-2 with the same map location number 
 
 in table A-2. placer occurrences have not been reported in the area.) 
 
 the location number does not appear 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig D 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and or 
 assay data 
 
 Production 
 and/or description 
 
 Refer- 
 ences 
 
 NORTHEAST ALASKA TREND 
 
 approx 6735 N. 
 141 = 15 W 
 
 Esotuk Glacier. 
 69=19N. 144"22W. 
 
 1 
 
 Pb. Zn. Sn. Cu 
 
 W 
 
 Up to 300 ppm Sn and 1 ,500 
 ppm W. 
 
 McCali Glacier. 
 69 : 18N. 14337 W. 
 
 1 
 
 Cu. Zn, Pb. Sn 
 
 
 NA 
 
 Bear Mountain. 
 68=23 N. 14205W. 
 
 2 
 
 Mo, W, Cb 
 
 
 60-180 ppm Cb in 
 open-ended 200-ft-wide by 
 4,000-ft-long geochemical 
 soil anomaly. 
 
 Mountain Creek. 
 6730N. 141M2W 
 
 3 
 
 Cu. Pb. Zn. Sn 
 
 Ag 
 
 Be, 
 
 140-800 ppm Sn and up to 10 
 pet Cu. 
 
 Rapid River lodes. 
 
 3 
 
 U. Sn. Pb. Zn, 
 
 3u 
 
 Several hundred parts per 
 
 million Sn, Pb, and Zn and 
 100 ppm U. 
 
 Skarn contains galena, sphalerite, 
 axinite, and quartz-tourmaline 
 veins. 
 
 Sulfides in deformed quartz veins 
 and schist along sheared 
 granite-quartz monzonite dike 
 contacts. Nearby occurrence of 
 fluorite in greisen in granite. 
 
 Soil anomaly corresponds to 
 Mo-W-mineralized gossan 
 associated with an altered 
 porphyry. Pyrochlore identified 
 in a pan concentrate. 
 
 Skarn mineralization adjacent to 
 rhyolite porphyry sills occurs as 
 thin lenses up to 50 ft long. 
 
 Greisen and veins in granite. 
 
 76-77 
 76-77 
 
 74 
 
 35-36 
 35-36 
 
 BROOKS RANGE TREND 
 
 Unnamed. 
 67-30 N. 155O0W 
 
 Unnamed. 
 6728 N. 155=06 W 
 
 Unnamed. 
 67"-24 N. 15245W 
 
 Kaiueh. 
 67-34 N. 15812W 
 
 Kiana. approx 
 67=30 N. 16033 W 
 
 Cu. Pb. Zn. Mo. Ag, NA 
 Sn 
 
 Au. Ag, Pb, Zn. Sn. 
 Mo 
 
 Ag. Cu. Zn. W. Sn. 
 B. Be. Bi. Cd. Sb 
 
 Pb. Zn, F. U, Sn, W, 
 
 Ag 
 Sn. Cb. Ta 
 
 Up to 55 ppm Au, 55 ppm Ag, 
 6.320 ppm Pb. 8.5000 ppm 
 Zn, and 450 ppm Sn in rock 
 samples. 
 
 700-1.000 ppm Sn and up to 
 20 ppm Ag. 1 100- by 300-ft 
 zone contains approx 1 pet 
 combined W0 3 and Sn. 
 
 NA 
 
 NA 
 
 Contact metamorphic 76 
 
 mineralization near contact 
 
 zone of granite. 
 Granite-metamorphic rock contact. 76, 78 
 
 Molybdenite and fluorite 
 
 present. 
 
 Tin disseminated and in skarn 7, 79 
 
 near contact of granite. 
 
 Mineralization in or near granite 80 
 
 contact. 
 
 Unevaluated report of cassiterite, 72-81 
 
 columbite, and tantalite in hills 
 north of Kiana, apparently in a 
 pegmatite. 
 
 SEWARD PENINSULA TREND 
 
 Setawik Hills area. 
 
 9 
 
 U. Cb. F 
 
 approx 6607 N. 
 
 
 
 160=15 W 
 
 
 
 Ear Mountain. 
 
 10 
 
 Sn, Cu. Au, Ag, Pb. 
 
 65=56 N. 16612W 
 
 
 Zn. U. Cb 
 
 Potato Mountain. 
 65=39 N. 167=34 W 
 
 Cape Mou r % - 
 65=35N. 16TS6W 
 
 fj 
 
 12 
 
 Sn. Cu. Pb. Zn 
 
 Sn 
 
 Several samples contained 
 20-90 ppm U and 150-500 
 ppm Cb. 
 
 2 pel Sn and 3 pet Cu 
 inferred over 1 ,000-ft-long 
 by 65-fl-wide zone. 0.01-0 1 
 pet Cb identified 
 spectrographically in 
 mineralized rock at Winfield 
 Shaft 
 
 Average grade of mineralized 
 zones may be approx 25 
 pet Sn Largest zone is 3 to 
 10 ft wide and 300 ft long 
 and may average 1 pet Sn 
 
 Average of 5- to 5.5-ft channel 
 samples was 6 5 pet Sn. 
 
 Altered zones in Selawik Hills 41 
 
 alkaline complex. Cb-U-Ti 
 
 mineral identified. 
 Cassiterite in skarn adjacent to 10, 29 
 
 small granite stock. 
 
 Cluster of cassiterite-bearing 4, 10, 
 
 quartz veinlets in tourmalinized 43 
 
 metasedimentary rocks. Small 
 
 irregular mineralized zones. 
 
 2.000 lb Sn reported to have 
 
 been produced (4). 
 Small, irregular, podlike 4, 42 
 
 replacement 
 
 cassitente-sericile-quartz- 
 
 tremolite bodies in limestone 
 
 adjacent to granite 12.000 lb 
 
 Sn produced 
 
 •■- ■■■ -■-..-* ace 
 
12 
 
 Table A-1. — Lode occurrences — Continued 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig. D 
 
 Lost River Mine, 
 65°28'N, 167°10'W. 
 
 13 
 
 Bessie Maple, 
 65°27'N, 167°12'W. 
 
 Rapid River lode, 
 65°24'N, 167°U'W. 
 
 Brooks Mountain, 
 65°31'N, 167°09'W. 
 
 13 
 13 
 
 13 
 
 Black Mountain, 
 65°31'N, 166°43'W. 
 
 14 
 
 Unnamed, 
 65°28'N, 
 
 165°37'W. 
 
 15 
 
 Kougarok, 
 65°40'N, 
 
 165°13'W. 
 
 16 
 
 Commodities Ore grade D . , 
 
 (in order of and/or ^ r0( ^ cUon t - 
 
 importance) assay data and/or description 
 
 SEWARD PENINSULA TREND— Continued 
 
 Sn, F, W, Be Proven and indicated 695,400 lb Sn produced. Skarn 
 
 reserves: 6.8 MM lb Sn and greisen bodies near or 
 
 grading 0.26 to 1 .3 pet in within granite or related rhyolite 
 
 cassiterite dike and 85 MM dikes. Be deposits located 
 
 lb Sn grading 0.151 pet in zonally away from Sn and F 
 
 cupola. Inferred reserves: deposits. Total proven and 
 
 16.6 MM lb Sn in cassiterite indicated reserves are 91.8 MM 
 
 dike and 4.4 MM lb Sn in lb Sn; total inferred reserves 
 
 Ida Bell Dike. 4.94 MM tons are 21 MM lb Sn. 
 
 fluorite reserves. Grades of 
 1 .0 to 2.0 pet Sn mined 
 from 1952 to 1955. 
 
 Sn, Ag, Pb, Cu, Sb, NA Sulfide-Sn replacement deposit is 
 
 Zn, W, Be, F flanked by fluoriteberyllium 
 
 deposits. No production noted. 
 
 Be, F, Sn NA Cassiterite encountered at depth 
 
 of several hundred feet in drill 
 core. Cupola may underlie area. 
 Granite stock intrudes 
 
 Sn, F, W, Pb, Zn, NA metasedimentary rocks. Small 
 
 Cu, Be replacement pod of sulfide 
 
 mineralization noted. 
 Sulfide-bearing skarn 
 
 Sn, W, Zn, Pb NA mineralization adjacent to 
 
 altered fault zone near biotite 
 granite. Minor greisen 
 developed. 
 Sn-bearing skarn found in 
 Sn > 1, 000 ppm Sn in skarn boulders of frostriven bedrock 
 
 samples. and scattered outcrops. 
 
 Sn, Ta, Cb 
 
 Omilak Mine, 
 65°04'N, 162°35'W. 
 
 Foster prospect, 
 65°04'N, 162°35'W. 
 
 Granite Mountain, 
 65°30'N, 161°08'W. 
 
 21 
 21 
 
 23 
 
 Ag, Pb, Sn, Sb 
 
 Ag, Pb, Sn, Au, Sb 
 
 Ag, Pb, Zn, Sn, Cb 
 
 Several ore zones defined 
 with 0.36-2.32 pet Sn and 
 potential for 0.01-0.03 pet 
 Ta and Cb. 
 
 0.2 pet Sn found in rock 
 sample. 
 
 High-grade ore contains 
 0.1-1.0 pet Sn. Trace to 0.3 
 pet Sn irregularly distributed 
 throughout 1.7- to 10.4-ft 
 drill intersections and 
 channel gossan samples. 
 
 Sn detected in 50 pet of 
 analyzed soil and rock 
 samples. Highest value was 
 500 ppm Sn in sulfide veins 
 in altered andesite. 
 Numerous pan concentrate 
 samples on north flank 
 contain detectable Cb 
 
 Mineralization consists of steep 
 cylindrical bodies and dikes of 
 greisenized granite, greisens 
 developed along tops of granite 
 sills, and veins and stockwork 
 in schist. 
 
 Several hundred tons Pb-Ag ore 
 produced from lenticular sulfide 
 body within limestone. 
 
 Gossan along fracture zone. Sn 
 apparently associated with Pb. 
 
 Numerous small argentiferous 
 galena-sphalerite-pyrite- 
 arsenopyrite-tourmaline 
 occurrences in 18-mi-long by 2- 
 to 5-mi-wide altered zone in 
 andesite and quartz monzonite. 
 
 Refer- 
 ences 
 
 4, 10, 
 21- 
 22, 
 82 
 
 4, 10 
 10 
 
 4, 10 
 
 10, 83 
 
 10 
 84-85 
 
 86 
 86 
 
 87, 75 
 
 KOKRINE-HODZANA TREND 
 
 Sithylemenkat, 
 66°03'N, 151°03'W. 
 
 Quartz Creek, 
 65°16'N, 151°22'W. 
 
 25 
 
 28 
 
 Sn, Cu, Pb, Zn, W, 
 Cb 
 
 Ag, Pb, Sn 
 
 0.23 pet Sn in greisen 
 samples. Up to 87 ppm Cb, 
 0.18 pet Cu, 3 4 pet Pb, 0.4 
 pet Zn, and 135 ppm W 
 also found in greisen 
 samples. 
 
 0.01-0.10 pet Sn in 
 mineralized samples. 
 
 Chlorite-magnetite greisen occurs 34 
 in rubble at head of east fork of 
 Kanuti Kilolitna River. 
 
 Work by the Bureau has shown a NAp 
 
 stockwork of quartz-galena 
 veins 0.5-6 in wide along a 
 zone approx 1 1 ft wide in 
 metasedimentary rocks. Minor 
 Ag production. Sn not 
 recovered. 
 
 YUKON-TANANA TREND 
 
 Porcupine Dome, 
 65°31'N, 145°32'W 
 
 Ketchem Dome, 
 65°27'N, 144°42'W. 
 
 33 
 33 
 
 Au, Ag, Sn 
 Sn, W 
 
 NA 
 
 2.3 pet Sn in high-grade 
 samples and 0.05-0.4 pet 
 Sn in channel samples of 
 vein zones. 0.5 pet Sn in 
 pegmatites. 
 
 Au-Ag-bearing quartz veins in 15-16 
 
 metasedimentary rock contain 
 
 cassiterite. 
 Greisen and pegmatites 15, 88 
 
 associated with multiple-phase 
 
 biotite granite. 
 
 NA Not available. NAp Not applicable. 
 
Table A-1. — Lode occurrences — Continued 
 
 13 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig 1) 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and 'or 
 assay data 
 
 Production 
 and or description 
 
 Refer- 
 ences 
 
 YUKON-TANANA TREND— Continued 
 
 Lime Peak. 
 6538N. 146-37W. 
 
 34 
 
 Sn. Cb 
 
 Janiksela. 
 64°58'N. 147"36 W 
 
 Cosna. 
 64°32N. 15V49 W 
 
 35 
 37 
 
 Sn 
 
 Pb. Sn. Ag 
 
 Stream sediments contain 
 anomalously large amounts 
 of Cu, Zn. Ba. Be. La. Mo. 
 Pb. Ag, Sn, Th, and U Pan 
 concentrate samples from 
 streams draining Lime Peak 
 summit contained the 
 following values, in 
 milligrams per pan: 
 43.6-561.8 Sn. 24.7-101.4 
 W. and 1.2-5.5 Cb. 60-1, 
 560 ppm Sn in greisen 
 samples. 
 
 NA 
 
 Samples of dumps and 
 mineralized rocks contained 
 traces to 3 18 pet Sn and 
 up to 80 pet Pb and 97 
 oz. ton Ag. Sample from 
 head of Tin Creek 
 reportedly contained 35 pet 
 Sn. 14 of 16 rock samples 
 collected from Fe-stained 
 zones in area contained 
 anomalously large 
 concentrations of Ag, Sn, 
 Bi, Be, Zn, Cu, Mo, and/or 
 Pb. 
 
 Multiple-phase biotite granite 15, 
 
 contains chlorite-sencite 37, 
 
 (topaz-tourmaline) greisen 89 
 
 zones. Work by the Bureau has 
 shown that greisen vein zones 
 up to 300 ft wide can be traced 
 for up to 6.000 ft along strike. 
 
 Cassiterite in pegmatite stringer 13 
 
 on contact of mica and graphitic 
 schists. 
 
 Apparently veinlike mineralization. 90-91 
 Numerous quartz veins and 
 rhyolite dikes within andulusite- 
 and tourmaline-bearing 
 hornfels suggest a granitic body 
 at depth. Cassiterite identified. 
 
 KUSKOKWIM TREND 
 
 Win claims. 
 63 : 29 N. 155 : 41 W 
 
 Won c a ~ 5 
 63 : 12N. 15554W 
 
 Mystery Mountain. 
 63=30N. 154<30W 
 
 Telida Mountains. 
 63 32N. 15309 W 
 
 38 
 
 39 
 
 40 
 
 Sn. Ag 
 
 Sn. Ag, Au 
 
 Sn. Pb 
 
 41 
 
 Sn 
 
 Beaver Mountains. 
 62°SON 15651W 
 
 Russ*ar Wc.' - ; m 
 61'40"N. 159'-07'W 
 
 43 
 
 45 
 
 Cb. Sn, Cu, Ag, 
 
 Cu. Au. Ag. Sn 
 
 Sn and sporadic Ag values in 
 rock samples. Anomalously 
 large concentration of Sn, 
 W, Bi, Ag, Zn, Pb, and As 
 in pan concentrates. 
 
 Sporadic Sn and Ag values in 
 rock samples. > 1.000 ppm 
 Sn in pan concentrate 
 samples. 
 
 Anomalously large 
 concentrations of Sn and Bi 
 in rock samples. Local 
 gossans contain Pb values 
 of several percent. Several 
 samples of nonmagnetic 
 heavy-mineral concentrates 
 contained > 1,000 ppm Sn. 
 
 Anomalously large 
 concentrations of Sn, Ag, 
 Bi, Cu. Mo, Pb, As, and Be 
 in rock samples of 
 tourmaline zones. Several 
 samples of nonmagnetic 
 heavy-mineral 
 concentrations contained 
 > 1,000 ppm Sn 
 
 200 and 1 ,000 ppm Cb in 2 
 samples of sulfide veinlet in 
 greisensenized basalt. 100 
 ppm Sn in channel samples 
 of Cu-Ag-rich 
 tourmaline-axinite-greisen 
 fracture fillings. 
 
 Typical mineralized rock 
 contains 1 pet Cu, 0.1 
 oz ton Au, and 1 .0 oz/ton 
 Ag, with local Sn values up 
 to 1 4 pet 
 
 Linear breccia zones within 59, 92 
 
 hornfelsed argillites. Hypabyssal 
 intrusions crop out nearby. 
 
 Breccia and quartz vein stockwork 59, 92 
 in horn-felsed argillite near 
 partially unroofed intrusion. 
 
 Large area of hornfels cut by 59 
 
 altered rhyolite dikes. Local 
 tourmaline flooding and 
 tourmalinized breccias. 
 
 Biotite granite intruding clastic 59 
 
 sedimentary rocks and gabbro. 
 Widespread tourmaline in 
 flat-dipping sheeted zones. 
 
 Veins and greisen zones in 93 
 
 monzonite and overlying basalt. 
 
 800-ft fissure vein within quartz 94-96 
 
 monzonite. 
 
 ALASKA RANGE TREND 
 
 \--.hz 1-ee- 
 
 56'N, 148M7W 
 
 Karmshna distnci. 
 63 35N. 15046 W 
 
 Long 1-%e- 
 63*11 N. 14939 W 
 
 47 
 
 48 
 
 49 
 
 Zn. Pb. Sn. Ag 
 
 Ag. Au. Sb. Cu. Pb, 
 Zn. W. Sn 
 
 Ag. Au. Cu. Bi. Sn 
 
 Average over 350 ft was 1 .4 
 pet Zn. 6 pet Pb. 035 
 pet Sn. and 3 oz ton Ag. 
 Higher grade 8-ft zone 
 within horizon contained 1 2 
 pet Sn. 
 
 NA 
 
 Up to 700 ppm Sn in rock 
 samples 
 
 Volcanogenic massive sulfide 66 
 
 hosted by siliceous exhalite 
 (identification uncertain) and 
 overlain by graphitic schists. 
 
 Cassiterite- and scheelite-bearing 97 
 
 cobbles reported to be coarse 
 
 and abundant in Caribou and 
 
 Glen Creeks; may suggest a 
 
 lode source nearby 
 Sn occurs in arsenopyrite-bearing 98-99 
 
 veins and is disseminated in 
 
 country rock within 300- by 
 
 600-ft area 
 
 NA Not available 
 
14 
 
 Table A-1— Lode occurrences— Continued 
 
 Name and 
 lat-long location 
 
 Ohio Creek, 
 63°11'N, 149°55'W. 
 
 Canyon Creek and 
 Ready Cash area, 
 63°09'N, 149°51'W. 
 
 Tired Pup, approx 
 61°20'N, 154°05'W. 
 
 Map 
 location 
 
 (fig- D 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and/or 
 assay data 
 
 Production 
 and/or description 
 
 ALASKA RANGE TREND— Continued 
 
 49 
 
 49 
 
 Sn, Ag, Au, Cu, Pb, 
 Zn, W, Cb 
 
 Ag, Sn 
 
 Coal Creek, 
 63WN, 149°51'W. 
 
 49 
 
 Sn, Ag, W, Zn 
 
 Tsusena Creek, 
 63°01'N, 148°40'W. 
 
 50 
 
 Ag, Cu, Pb, Zn, Sn 
 
 Boulder Creek 
 (Purkeypile), 
 62°53'N, 152°08'W. 
 
 51 
 
 Sn, Ag 
 
 53 
 
 Sn, U 
 
 >0.10 pet Sn in gresien 
 samples. Anomalous Sn, W, 
 Ag, Pb, Bi, Be, and Zn in 
 stream sediment samples. 
 
 Rock samples of veins 
 average 20 oz/ton Ag and 
 0.1-1.0 pet Sn. 
 
 Rock samples contain 
 0.002-1 .5 pet Sn and are 
 reported to average >0.2 
 pet Sn. 2 samples assayed 
 2.9 and 4.3 oz/ton Ag. 
 
 Channel samples of vein 
 yielded 0.5 pet Sn over 4 ft 
 and 0.10 pet Sn over 10 ft. 
 
 Up to 18 pet Sn and 230 
 oz/ton Ag. 12 of 24 drill hole 
 intersections contained 
 >0.53 pet Sn; average of 
 2.41 pet Sn over a 9-ft vein 
 width. 1.11-9.47 oz/ton Ag 
 found over lengths of 2-34 ft 
 in 9 of 24 drill holes. 
 
 Up to 1 ,000 ppm Sn in stream 
 sediment samples. 
 
 Cassiterite-bearing 
 muscovite-tourmaline greisen, 
 probably limited in extent. 
 
 Vein potential reported in 
 hundreds of thousands of tons. 
 1 vein, 400 ft of which averaged 
 0.5 pet Sn, has about 25,000 
 ton potential. 
 
 Inferred ore reserves of >5 MM 
 tons of >0.2 pet Sn associated 
 with multiple-phase biotite 
 granite. Ore body consists of 
 stockwork greisen veins. 
 
 Sheeted veins within felsic to 
 intermediate volcanic flows, 
 tuffs, breccia, and agglomerate. 
 
 300,000 lb Sn proven and 1 .05 
 MM lb Sn inferred (24) within 
 stockwork of cassiterite-sulfide 
 veinlets along a probable 
 fracture zone near granite. 
 Work by Reed (26) suggests 
 substantially lower Sn reserves. 
 
 Reported Sn-U mineralization. 
 
 Refer- 
 ences 
 
 39 
 99-100 
 
 39 
 98-100 
 
 24, 
 39, 
 101 
 
 88 
 
 25, 
 
 28, 
 
 39, 
 
 102- 
 
 103 
 
 40 
 
 OTHER OCCURRENCES 
 
 Valley of Ten Thousand 
 Smokes, 
 58°18'N, 155°18'W. 
 
 Copper Mountain, 
 60°47'N, 146°34'W. 
 
 Bokan Mountain, 
 55°55'N, 132°09'W. 
 
 54 
 
 55 
 
 Sn, Pb, Zn 
 
 Sn 
 
 Rude River, 
 
 56 
 
 Sn 
 
 60°45'N, 145°19'W. 
 
 
 
 Tarr Inlet Knob, 
 
 57 
 
 Au, Ag, Cu, Pb, Zn 
 
 58°57'N, 136°54'W. 
 
 
 Sn 
 
 Johns Hopkins Inlet, 
 58 53'N, 137°01'W. 
 
 58 
 
 Cu, Au, Ag, Sn, Vv 
 
 Edelweiss prospect, 
 58°04'N, 134°27'W. 
 
 59 
 
 U, Th, Zr, Cs, Cb, 
 REE 
 
 Salmon Bay, 
 56°19'N, 133°10'W. 
 
 60 
 
 Th, REE, Cb 
 
 61 
 
 U, Th, REE, Pb, Cb, 
 Be 
 
 0.019 pet Sn, 0.054 pet Pb, 
 and 0.034 pet Zn found in 
 precipitate in throat of 
 fumarole. 
 
 0.5 pet Sn in sample of 
 quartz-cemented breccia 
 found in float. 
 
 0.17 pet Sn in pyritiferous 
 slate. 
 
 Channel samples up to 
 10-ft-long contained 50-200 
 ppm Sn and up to 0.68 pet 
 Cu, 4.3 pctZn, 0.15 pet Pb, 
 100 ppm Ag, and 0.70 ppm 
 Au. 
 
 Rock sample contained 
 4,100 ppm Cu, 0.15 ppm 
 Au, 7 ppm Ag, 700 ppm Sn, 
 and 793 ppm W. 
 
 Heavy-mineral concentrate 
 samples contained trace to 
 major amounts Cb. 
 
 Average of 290 ppm Cb (high 
 of 700 ppm) in 5 samples of 
 felsic dikes associated with 
 mineralized veins. 100 ppm 
 Cb in some vein material. 
 
 12 ore samples from Ross 
 Adams Mine averaged 1.1 
 pet U and 0.01 pet Cb. 
 Other prospects contain 
 0.003-1 .0 pet Cb associated 
 with U mineralization over 
 widths probably < 1-6 ft. 
 
 Precipitate consists largely of 
 opal, gypsum, and traces of 
 arsenic sulfide and barium 
 sulfate. 
 
 Host rock may be greenstone. 
 
 Red-stained zone in 
 metasedimentary rocks. 
 
 Mineralized fault zones in 
 porphyritic granite and quartz 
 monzonite. 
 
 Hornfels in float. 
 
 Rare-earth-bearing pegmatite. 
 
 Radioactive carbonate-hematite 
 veins and nonradioactive 
 rare-earth carbonate veins 
 found along 8 mi of coast. 
 
 94,000 tons ore grading approx 1 
 pet U mined from Ross Adams 
 Mine to 1971. Cb not 
 recovered. Mineralization 
 consists of disseminated U-Th 
 accessory minerals in 
 pegmatite, aplite, and 
 peralkaline granite; 
 hydrothermally deposited U-Th 
 minerals in or near fractures; 
 and U-Th minerals in interstices 
 of quartzite. Columbite and 
 pyrochlore identified. 
 
 65 
 
 104 
 
 104 
 105 
 
 105 
 
 73 
 106-107 
 
 70-71 
 
 REE Rare-earth elements. 
 

 
 
 
 
 
 15 
 
 
 
 
 Table A-2. 
 
 —Placer occurrences 
 
 
 
 (For lode occurrences in the vicinity of a listed location, see listings in table A-1 with the same map location 
 
 number If the location number does not appear in 
 
 
 
 table A-1. 
 
 lode occurrences have not been reported in the area.) 
 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 
 (fig 1) 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and or 
 assay data 
 
 Production 
 and or description 
 
 Refer- 
 ences 
 
 NORTHEAST ALASKA TREND 
 
 Bear Mountain. 
 
 2 
 
 W. Cb 
 
 
 Concentrate from bulk sample 
 
 Downstream from Bear Mountain 
 
 74 
 
 68 23 N. 142 05 W 
 
 
 
 
 of gravel contained 3-12 pet 
 WO\ and up to 15 pet Cb. 
 
 lode Pyrochlore-like mineral 
 
 
 
 
 
 
 identified. 
 
 
 Rapid River. 
 
 3 
 
 Sn. W. 
 
 REE. U. Cb. 
 
 1.6-21.0 pet Sn in 
 
 Potentially very large reserves in 
 
 35 
 
 67=38 N. 141=20 W. 
 
 
 
 
 monazite-rich concentrates 
 from sluicebox samples. 
 0.04-5.7 lb yd 3 Sn. 
 0.14-0.75 pet associated W 
 and 0.05-0.1 pet Cb. 
 
 basin. 
 
 
 Porcupine River. 
 
 3 
 
 Sn. REE 
 
 Up to 0.7 pet Sn in pan 
 
 Potential for large, low-grade 
 
 35 
 
 67-21 N. 141=17 W 
 
 
 
 
 concentrate sample of 
 ancient channel gravels. 
 Cassiterite identified. 
 
 reserves in terrace deposits. 
 
 
 BROOKS RANGE TREND 
 
 Gold Bench. 
 
 8 
 
 Au. Sn 
 
 
 Cassiterite in concentrates 
 
 Only Au recovered 
 
 108 
 
 6659 N. 150=19 W 
 
 
 
 
 
 
 
 SEWARD PENINSULA TREND 
 
 Kreoger and Eldorado 
 
 10 
 
 Sn 
 
 
 Unweighted average for 26 
 
 Creeks drain Ear Mountain stock 
 
 10. 29 
 
 Creeks 
 
 
 
 
 churn drill holes in Kreuger 
 
 and contact zone. No mining 
 
 
 65=56 N. 166'07'W. 
 
 
 
 
 and Eldorado Creeks was 
 0.3 lb yd 3 over 10-ft mining 
 section. 
 
 reported. 
 
 
 Tuttte Creek. 
 
 10 
 
 Sn. Cb 
 
 
 Trace to 1.2 Ibyd 3 Sn in 
 
 No mining reported 
 
 29 
 
 65=56 N. 1S6=2rW. 
 
 
 
 
 placer samples. Traces of 
 Cb also present. 
 
 
 
 Potato Creek. 
 
 11 
 
 Sn 
 
 
 Composite sample of 
 
 do 
 
 43 
 
 65=40N. 167=39W 
 
 
 
 
 concentrate contained 45.22 
 pet Sn. Average for 15 
 churn drill holes was 0.2 
 lb yd 3 Sn in pay streak. 
 
 
 
 Buck Creek 
 
 11 
 
 Sn 
 
 
 Average of 3.9 lb yd 3 Sn in 
 
 From 1902 to 1953, 2,204,600 lb 
 
 43 
 
 65=39 N. 167*31 W. 
 
 
 
 
 pay streak Averages of 1 .0 
 and 1.1 lb/yd 3 Sn in upper 
 (17 samples) and west (18 
 samples) forks of Buck 
 Creek, respectively. 
 
 Sn produced from 560,000 yd 3 
 of gravel (including Grouse 
 Creek). Largely mined out. 
 
 
 Peluk Creek. 
 
 11 
 
 Sn 
 
 
 Composite sample of 
 
 Some mining possibly occurred 
 
 10. 43 
 
 6539 N. 1 67=31 W. 
 
 
 
 
 concentrate contained 53 46 
 pet Sn. 0.01-0.77 lb/yd 3 Sn. 
 Average for 2 churn drill 
 holes near creek mouth was 
 0.5 Ibyd 3 Sn in pay streak. 
 
 near mouth of creek. 
 
 
 Sutter Creek. 
 
 11 
 
 Sn 
 
 
 Abundant Sn occurs near 
 
 Mining extends 1,000 ft from 
 
 10. 43 
 
 6538 N. 167=31 W. 
 
 
 
 
 mouth of Iron Creek. Up to 
 90 lb/yd 3 cassiterite 
 recovered Average for 30 
 churn drill holes was 0.2 
 lb yd 3 Sn in pay streak. 
 
 mouth of Iron Creek. 
 
 
 Iron Creek. 
 
 11 
 
 Sn 
 
 
 Gravels containing 3.38 lb yd 3 
 
 1.500-ft section along stream bed 
 
 10. 43 
 
 65=39 N. 16733'W 
 
 
 
 
 Sn mined in 1917. Average 
 for 1 1 churn drill holes was 
 0.6 lb yd 3 Sn in pay streak. 
 
 was hand-mined; unknown 
 amount of Sn recovered. 
 
 
 Oakland C 
 
 11 
 
 Sn 
 
 
 15 churn drill samples in pay 
 
 Pay streak extends about 1 mi 
 
 43 
 
 65 41 N. 167=36 W 
 
 
 
 
 streak averaged 0.10 lb/yd 3 
 Sn. 
 
 along creek near western base 
 of Potato Mountain. 
 
 
 Grouse Creek 
 
 11 
 
 Sn 
 
 
 Average of 2.9 lb yd 3 Sn in 
 
 See Buck Creek for production. 
 
 10. 43 
 
 65'39 N 167 34W 
 
 
 
 
 pay streak 
 
 Mining extends 5,000 ft 
 downstream from mouth of 
 Buck Creek Largely mined out. 
 
 
 . -.-.• I--- 
 
 12 
 
 Sn 
 
 
 Average for 8 churn drill holes 
 
 No mining reported 
 
 42, 
 
 65'37N. 168D3W 
 
 
 
 
 was 0.18 lb/yd 3 Sn 
 
 
 109- 
 110 
 10. 23, 
 
 Boulder Creek. 
 
 12 
 
 Sn. Cb 
 
 
 Average values in churn 
 
 Pay gravels extend at least 4,000 
 
 6537 N. 167=59 W 
 
 
 
 
 drill-hole lines in pay streak: 
 12-17 Ibyd 3 Sn. 22 churn 
 drill samples from pay 
 streak yielded average of 
 10 Ibyd 3 Sn 01-0 1 pet 
 Cb detected in a composite 
 concentrate sample. 
 
 ft along creek, but no mining 
 recorded. 
 
 109- 
 110 
 
 Qoodv. - C-ee« 
 
 12 
 
 Sn 
 
 
 Composite concentrate 
 
 Several hundred pounds 
 
 10, 42, 
 
 65'35N. 167=54W 
 
 
 
 
 sample contained 58 5 pet 
 Sn. Average grade of 2 
 churn drill samples from pay 
 streak at mouth of Goodwin 
 Gulch was 4 Ibyd' Sn 
 Average for 3 churn drill 
 holes m pay streak at 
 mouth of Wales Creek was 
 1 lb yd 3 Sn. 
 
 cassiterite concentrate 
 recovered from narrow 
 1.000-ft-long pay streak. 
 
 109- 
 110 
 
 REE Rare-earth elements 
 
 
 
 
 
 
 
16 
 
 Table A-2. — Placer occurrences — Continued 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig- 1) 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and/or 
 assay data 
 
 Production 
 and/or description 
 
 Refer- 
 ences 
 
 SEWARD PENINSULA TREND— Continued 
 
 First Chance Creek, 
 65°35'N, 167°56'W. 
 
 Cape Creek, 
 65°37'N, 167°59'W. 
 
 Anikovik River, 
 65°31'N, 167°36'W. 
 
 Creeks, 
 
 64°57'N, 162°12'W. 
 
 12 
 
 12 
 
 Sn, Cb, Ta 
 
 Sn, Cb, Ta 
 
 13 
 
 Sn, Au 
 
 Cassiterite Creek, 
 
 13 
 
 Sn, W, Cb 
 
 65°28'N, 167°10'W. 
 
 
 
 Lost River, 
 
 13 
 
 Sn 
 
 65°27'N, 167°10'W. 
 
 
 
 Rapid River, 
 
 13 
 
 Sn 
 
 65°27'N, 167°12'W. 
 
 
 
 Kougarok River area 
 
 16 
 
 Au, Sn, Cb 
 
 (Washington and Mascot 
 
 
 
 Creeks), 
 
 
 
 65°44'N, 164°58'W. 
 
 
 
 Humboldt Creek, 
 
 16 
 
 Au, Sn, Cb 
 
 65°49'N, 164°25'W. 
 
 
 
 Hannum Creek, 
 
 17 
 
 Au, Sn, Pb 
 
 65°54'N, 163°11'W. 
 
 
 
 Otter Creek, 
 
 18 
 
 Au, Sn 
 
 65°06'N, 162°23'W. 
 
 
 
 Monument Creek, 
 
 19 
 
 Au, Sn 
 
 64°36'N, 165°30'W. 
 
 
 
 Rocky Mountain Creek, 
 
 20 
 
 Au, Sn, W 
 
 64°46'N, 165°12'W, 
 
 
 
 Clear and Vulcan 
 
 22 
 
 Cb, Sn, U, W 
 
 20 churn drill holes yielded 
 average of 1.0 lb/yd 3 Sn in 
 pay streak that extends 
 1 ,500 ft up creek from 
 mouth. Traces of Cb and Ta 
 present. 
 
 32 churn drill holes near 
 mouth of creek averaged 
 0.2 lb/yd 3 Sn. 48 churn drill 
 holes above mouth of First 
 Chance Creek averaged 4.5 
 lb/yd 3 Sn. Total inferred 
 reserves, including gravels 
 below First Chance Creek, 
 average 2.6 lb/yd 3 Sn. 
 Trace of Cb and Ta 
 detected. 
 
 31 pet Sn in concentrate. 
 
 156,000 yd 3 of mined 
 
 gravels averaged 0.003 
 
 lb/yd 3 Sn. 
 Mine records indicate 3.6 
 
 lb/yd 3 Sn was mined. Trace 
 
 Cb detected. 
 0.04-0.35 lb/yd 3 Sn found in 6 
 
 churn drill holes. 
 Trace of Sn found in 2 churn 
 
 drill holes. 
 Cassiterite in concentrate. 
 
 Concentrates show 60 pet Sn 
 and trace Cb. 
 
 Cassiterite and Pb minerals in 
 
 concentrate. 
 >5,000 ppm Sn in pan 
 
 concentrate sample. 
 Cassiterite reported. 
 
 Cassiterite reported in placer 
 concentrates. 
 
 500-800 ppm Cb in pan 
 concentrate samples. 1 pet 
 Cb found in composite 
 samples of concentrates 
 from 19 test pits (0.03-0.18 
 lb/yd 3 Cb). 
 
 Some past mining is evident. 
 Production may be credited to 
 Cape Creek. 
 
 Delta-like deposit in beach gravels 
 at mouth of Cape Creek and 
 alluvial deposits in upper creek. 
 Production, including Goodwin 
 Gulch, from 1924 to 1975 was 
 1 .537 MM lb Sn. Production 
 from Cape Creek is presently 
 1 50,000-200,000 lb cassiterite 
 concentrate per year. 550,250 
 lb Sn produced from 1 979 to 
 1982. Calculated inferred Sn 
 reserves: 2.2 MM lb within 
 850,000 yd 3 gravel. 
 
 496 lb Sn produced from within 
 0.5 mi of river mouth in 1914 
 and 1915. 
 
 93.4 tons Sn recovered from 
 52,000 yd 3 of gravel from 1 949 
 to 1951. 
 
 Pits irregularly distributed over 
 19-mi length of several creeks. 
 
 10, 42, 
 
 109- 
 
 110 
 
 6-7, 10 
 23, 42 
 109- 
 110 
 
 10, 46 
 
 4, 46 
 
 Cassiterite not mined. 
 
 46 
 
 No mining reported 
 
 10, 46 
 
 Intermittent mining to 1968. 
 Cassiterite not recovered. 
 
 75, 111 
 112 
 
 Coarse cassiterite hampered Au 
 recovery. In 1919, a few 
 hundred pounds cassiterite was 
 saved but not shipped. 
 
 Mined for Au; no cassiterite 
 recovered. 
 
 Evidence of past mining; some 
 recovery of Sn reported. 
 
 Mined for Au 
 
 84, 
 111 
 
 109, 
 111 
 9, 63 
 
 109 
 
 do 
 
 109 
 
 44 
 
 KOKRINE-HODZANA TREND 
 
 Hogatza, 
 
 66°11'N, 155°43'W. 
 Sithylemenkat pluton 
 
 area 
 
 66°03'N, 151°00'W. 
 
 24 
 25 
 
 Au, Sn, PGM 
 Sn, W, Ta, Cb 
 
 Hot Springs pluton 
 
 26 
 
 Sn 
 
 
 area, 
 
 
 
 
 66°20'N, 150°46'W. 
 
 
 
 
 Fort Hamlin Hills 
 
 27 
 
 Sn, 
 
 Cb 
 
 pluton area. 
 
 
 
 
 66°07'N, 150°08'N 
 
 
 
 
 Tozimoran and Ash 
 
 29 
 
 Au, 
 
 Sn 
 
 Creeks, 
 
 
 
 
 65°30'N, 153°00'W. 
 
 
 
 
 Melozimoran Creek, 
 
 29 
 
 Au, 
 
 Sn 
 
 65°23'N, 152°49'W. 
 
 
 
 
 Mason Creek, 
 
 30 
 
 Au, 
 
 Sn 
 
 65°11'N, 153°19'W. 
 
 
 
 
 Cassiterite and PGM identified 
 in concentrates. 
 
 Trace to 0.404 lb/yd 3 Sn in 
 bulk gravel samples from 
 upper east fork and 0.08 
 lb/yd 3 Sn from main branch 
 of Kanuti Kilolitna River. 21 
 of 35 placer concentrate 
 samples contained average 
 of 0.26 pet Cb; 35 
 concentrate samples 
 contained average of 06 
 pet Ta. 
 
 Several pan concentrate 
 samples contained 
 1,000-7,000 ppm Sn. 
 
 Pan concentrate samples 
 contained 7,000->10,000 
 ppm Sn and trace Cb. 
 
 Churn drilling showed 0.73 
 lb/yd 3 Sn over 650- by 80-ft 
 block of ground on 
 Tozimoran Creek. 2-3 pet 
 Sn in concentrates from 
 Ash Creek. 
 
 Trace Sn in lower creek. 
 
 Concentrate recovered in 
 1918 averaged 0.5 lb/yd 3 
 Sn. 
 
 Dredge operation in glaciofluvial 
 deposits recovers Au. 
 
 Sn-bearing gravels in streams 
 draining Ray Mountain and 
 Sithylemenkat plutons. 
 
 No mining reported 
 
 Creeks draining northwestern 
 portion of Fort Hamlin Hills. 
 
 Approx 13,000 lb Sn produced 
 from Tozimoran Creek in 
 1938-43 and 1983. 
 Cassiterite-bearing cobbles 
 reported. No production from 
 Ash Creek. 
 
 No mining reported 
 
 Unconfirmed report of 1 ton 
 cassiterite concentrate 
 recovered from 4,000 yd 3 of 
 gravel in 1918. No cassiterite 
 found in 1944. 
 
 13, 
 109 
 
 33-34 
 
 33-34 
 33-34 
 
 12, 14, 
 18 
 
 14, 18 
 14 
 
 PGM Platinum-group metals. 
 
17 
 
 Table A-2. — Placer occurrences — Continued 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig 1) 
 
 Commodities 
 
 (m order ot 
 importance) 
 
 Ore grade 
 
 and or 
 assay data 
 
 Production 
 and or description 
 
 Refer- 
 ences 
 
 KOKRINE-HODZANA TREND— Continued 
 
 Morelock and Bonanza 
 Creeks. 
 65"19N. 151=20W 
 
 Big Creek. 
 64=40 N. 155"29 W 
 
 Birch Creek. 
 64=28 N. 1 55=22 W 
 
 Monument Creek. 
 
 64=19 N. 155=23 W 
 Poorman Creek. 
 
 64=06 N. 15532 W 
 Short Creek. 
 
 64=19N. 15533W 
 
 Spruce Creek. 
 64=09 N. 1 55=28 W 
 
 Straight Creek. 
 64=23 N. 155=23 W 
 
 31 
 
 Au. Sn 
 
 32 
 
 32 
 
 32 
 32 
 
 Au. Sn 
 
 Au. Sn 
 
 Cox Gulch. 
 64=40 N. 155=29 W 
 
 32 
 
 Au. Sn 
 
 Crooked Creek. 
 
 64=28 N. 155=23 W 
 Fifth of July Creek. 
 
 64=23 N. 155=33W. 
 
 32 
 32 
 
 Au. Sn 
 Au. Sn 
 
 Rint Creek. 
 
 64=24 N. 155=23 W 
 Glacier Creek. 
 
 64=40 N. 155=29W 
 
 32 
 32 
 
 Cb 
 
 Au. Sn. Bi 
 
 Greenstone Creek. 
 64=18N. 15532W 
 
 32 
 
 Au. Sn 
 
 Long Creek. 
 64=23 N. 15532W. 
 
 32 
 
 Au, Sn 
 
 Midnight Creek 
 64=19 N. 155=32 W 
 
 32 
 
 Au, Sn 
 
 32 
 
 Sn, Cb 
 
 32 
 
 Au, Sn 
 
 32 
 
 Au. Sn 
 
 Au. Sn 
 Au, Sn 
 
 Trace to 0.18 lb Sn per 
 square foot of bedrock in 
 pay streak at Morelock 
 Creek. 15 lb Sn per 
 square foot of bedrock 900 
 ft above mouth of Bonzana 
 Creek. 47 3-65.2 pet Sn in 6 
 concentrate samples from 
 different parts of pay streak. 
 
 Cassiterite in headwaters. 
 
 Min 0.01-0 04 lb cassiterite 
 per square foot of bedrock 
 in pay streak. 0.5 lb 
 cassiterite per square foot 
 of bedrock recovered from 
 88,900 ft 2 of underground 
 workings. 
 
 0.2-033 lb Sn per square foot 
 of bedrock. 
 
 Sn reported 
 
 Sn-bearing area is approx 1.5 mi 
 long and 400- to 500-ft wide on 
 Morelock Creek and at least 
 900 ft up Bonanza Creek. 
 Probably about 2 ft of irregularly 
 distributed pay streak. Sn 
 recovered from a few small 
 cuts. 
 
 Pay streak estimated to be 5,000 
 
 ft long, 30 ft wide, and 1-15 ft 
 
 thick. Approx 1.100 lb 
 
 cassiterite concentrate 
 
 recovered. 
 At least 5,000 lb cassiterite 
 
 concentrate recovered 1914-36 
 
 Pay streak on bench estimated 
 
 to cover 18 acres. 
 
 Cassiterite very coarse, approx 
 1 ,000 lb cassiterite concentrate 
 recovered. 
 
 Au mining just above Birch Creek. 
 
 Cassiterite common in 
 concentrates. 
 
 Approx 300 lb Sn represents 
 incomplete recovery from 
 approx 6,000 ft 2 of bedrock. 
 
 Trace Cb detected in Cb not recovered 
 
 concentrates. 
 
 NA 1 50 lb cassiterite concentrate 
 
 recovered. Pay streak 
 estimated to cover 12 acres. 
 
 NA Approx 300 lb cassiterite 
 
 recovered 1940-42. Pay streak 
 estimated to cover 18 acres. 
 
 NA Cassiterite reported in Au 
 
 concentrates. Pay streak 
 estimated to cover 61 acres 
 and to be at least 6.4 mi long. 
 
 Cassiterite recovered 7320 lb cassiterite concentrate 
 
 averaged 0.06 lb/yd 3 . produced in 1940-42. 1,037 lb 
 
 concentrate containing 537 lb 
 Sn produced in 1917-18. Pay 
 streak estimated to cover 9 
 acres. 
 
 Trace Sn and Cb detected in Sn and Cb not recovered, 
 
 concentrates. 
 
 Some cassiterite reported. 
 
 Cassiterite is common 
 
 Cassiterite reported. 
 NA 
 
 Pay streak estimated to cover 61 
 
 acres. 
 In 1918, a few thousand pounds 
 
 of cassiterite was recovered 
 
 from placer workings 1-1.5 mi 
 
 long, 20-40 ft wide, and 10-15 ft 
 
 deep. 
 Cassiterite not produced. Pay 
 
 streak estimated to cover 6 
 
 acres. 
 Unconfirmed report of cassiterite 
 
 recovered with Au in lower 
 
 portion of creek 
 
 13-14, 
 113 
 
 14 
 
 14, 114 
 
 14 
 
 14 
 14 
 
 75 
 
 14, 114 
 
 14. 114 
 14, 114 
 
 14, 114 
 
 75 
 
 13, 114 
 
 13-14 
 
 13, 114 
 14 
 
 YUKON-TANANA TREND 
 
 Yankee Creek. 
 
 6532 N. 145=23 W 
 Mastadon Creek. 
 
 65=29 N 145=18 W 
 
 nr'i'€ O ©V*. 
 
 65'31 N. 145=14 W 
 Granite Gulch. 
 
 6530 N. 145=12 W 
 Harrison Creek. 
 
 65=25N 145'14'W 
 
 Bedrock Creek. 
 6530 N 14507W 
 
 Boulder Creek. 
 6529 N. 145=03 W 
 
 33 
 
 Au Sn 
 
 33 
 
 Au, Sn 
 
 33 
 
 Au. Sn 
 
 33 
 
 Au. Sn. W 
 
 33 
 
 Au. Sn 
 
 33 
 
 33 
 
 Sn. W 
 
 Au. Sn. W 
 
 Cassi'ente associated with 
 
 placer Au. 
 Cassiterite reported in 
 
 concentrates. 
 > 1 pet Sn in sluice-box 
 
 sample. 
 Sluicebox sample contained 
 -40 pet Sn and 4 pet W 
 Sluicebox sample from upper 
 
 portion of creek contained 
 •1 pet Sn. 
 Pan concentrate samples 
 
 showed anomalously large 
 
 concentrations of Sn and 
 
 W 
 Estimate of ^2 lb/yd 3 
 
 cassiterite at mine site 63 
 
 pel cassiterite and 2 pet 
 
 scheehte in sluice-box 
 
 concentrates 
 
 Cassiterite not recovered. 
 
 15 
 
 
 Pay streak in lower valley is 200 ft 
 
 wide and 7-10 ft thick 
 Cassiterite not recovered. Pay 
 
 streak has max width of 50 ft. 
 
 15 
 15- 
 
 16 
 
 Cassisterite not recovered. 
 
 16 
 
 
 do 
 
 16 
 16 
 
 
 do 
 
 
 Pay streaks limited to 200- to 
 300-ft wide and 4- to 15-ft-deep 
 alluvial gravels. Some 
 concentrate recovered 
 
 16 
 
 •.a •.:■ ,.-. ■-.'.<■. 
 
18 
 
 Table A-2. — Placer occurrences — Continued 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig- D 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and/or 
 assay data 
 
 Production 
 and/or description 
 
 Refer- 
 ences 
 
 YUKON-TANANA TREND— Continued 
 
 Deadwood Creek 
 (Switch Creek), 
 65°28'N, 144°57'W. 
 
 Ketchem Creek, 
 65°29'N, 144°45'W. 
 
 Half Dollar Creek, 
 
 65°25'N, 144°37'W. 
 Portage Creek, 
 
 65°26'N, 144°37'W. 
 
 Twin Creek, 
 
 65°02'N, 147°27'W. 
 Gilmore Creek, 
 
 64°59'N, 147°25'W. 
 Cache Creek, 
 
 65°06'N, 150°48'W. 
 
 Dalton Gulch, 
 65WN, 150°50'W. 
 
 Deep Creek area, 
 65°04'N, 150°58'W. 
 
 33 
 
 Au, Sn, W 
 
 33 
 
 Au, 
 
 Sn, W 
 
 33 
 
 Au, 
 
 Sn, W 
 
 33 
 
 Au, 
 
 Sn, W, Cb 
 
 35 
 
 Au, 
 
 W, Sn 
 
 35 
 
 Au, 
 
 Sn, Cb 
 
 36 
 
 Au, 
 
 Sn, Cb 
 
 36 
 
 Au, 
 
 Sn, Cb 
 
 36 
 
 Au, 
 
 Sn, Cb 
 
 Ferguson Draw and 
 Harter Gulch, 
 65°06'N, 150°51'W. 
 
 Gold Basin Creek, 
 65°07'N, 150°45'W. 
 
 Idaho and Tofty 
 Gulches, 
 65°05'N, 150°52'W. 
 
 36 
 
 36 
 36 
 
 Au, Sn 
 
 Au, Sn 
 Au, Sn, Cb 
 
 Woodchopper Creek, 
 65°03'N, 151°01'W. 
 
 36 
 
 Au, Sn, Cb 
 
 Average of 1 -2 lb/yd 3 
 concentrates (principally 
 wolframite and cassiterite). 
 2 sluicebox concentrate 
 samples from Switch Creek 
 showed approx 10 pet Sn 
 and 2 pet W. 
 
 Cassiterite in concentrates. 
 >1 pet Sn and >1 pet W in 
 sluicebox sample. 
 
 Cassiterite abundant and 
 scheelite common. 
 
 Sluicebox sample contained 
 >1 pet Sn and trace Cb. 
 
 Cassiterite common 
 
 Trace Cb in concentrates. 
 
 Average of 0.019 lb/yd 3 Cb 
 and 2.26 lb/yd 3 Sn found in 
 channel samples of tailings. 
 
 Average of 3.9 lb/yd 3 Sn and 
 0.0002 lb/yd 3 Cb 2 O s found 
 in 5 channel samples of 
 tailings. 
 
 Average of 1 .98 lb/yd 3 Sn and 
 0.10 lb/yd 3 Cb 2 O s in 26 
 channel samples of tailings. 
 
 0.1-0.4 lb cassiterite per 
 square foot of bedrock in 
 pay streak at Ferguson 
 Draw. 4 channel samples of 
 tailings from Harter Gulch 
 showed an average of 0.27 
 lb/yd 3 Sn and trace Cb 2 5 . 
 
 NA 
 
 5 channel samples of tailings 
 from Idaho Gulch averaged 
 1.0 lb/yd 3 Sn and 0.019 
 lb/yd 3 Cb 2 5 . 
 
 Killarney Creek, 
 65°07'N, 150°44'W. 
 
 36 
 
 Au, 
 
 Sn 
 
 Cassiterite reported. 
 
 Miller Gulch, 
 65°05'N, 150°56'W. 
 
 36 
 
 Au, 
 
 Sn, Cb 
 
 16 channel samples of tailings 
 averaged 0.775 lb/yd 3 Sn 
 and 0.03 lb/yd 3 Cb 2 5 . Up 
 to 7 pet Cb 2 5 in 
 concentrates. 
 
 Patterson Creek, 
 
 65°05'N, 150°54'W. 
 Sullivan Creek, 
 
 65°07'N, 150°55'W. 
 
 36 
 36 
 
 Au, 
 Au, 
 
 Sn 
 Sn, Cb 
 
 NA 
 
 Tailings average 0.241 lb/yd 3 
 Sn and trace Cb. 
 
 12 channel samples of tailings 
 averaged 0.72 lb/yd 3 Sn 
 and 0.010 lb/yd 3 Cb 2 5 . 
 1.2-1.3 lb cassiterite per 
 square foot of bedrock 
 recovered at south end of 
 pay streak. 
 
 Cassiterite recovered from 
 concentrates during early 
 mining. Pay streak reported to 
 be about 9 mi long. 
 
 Cassiterite not recovered. 
 
 ..do 
 
 Cassiterite not recovered. 
 
 Bismuthinite and wolframite 
 
 also present. 
 May have most abundant 
 
 cassiterite in Fairbanks district. 
 Only Au recovered 
 
 5,155 lb cassiterite concentrate 
 recovered 1909-56. Aeschymite 
 [(Ce, Ca, Fe, Th)(Ti, Cb) 2 (0, 
 OH) 6 ] reported. 
 
 3,000 lb cassiterite concentrate 
 produced from discontinuous 
 pay streaks, 1909-56. 
 
 Columbite [(Fe, Mn)(Nb, Ta) 2 6 ] 
 and aeschymite reported. 
 64,200 lb concentrate averaging 
 56 pet Sn produced from drift 
 mining. Pay streak estimated to 
 cover 18 acres. 169,400 lb 
 indicated Sn reserves in tailings 
 of Woodchopper and Deep 
 Creeks. 
 
 Harter Gulch and Ferguson Draw 
 pay streak estimated to cover 
 27 acres. 
 
 Unverified Sn production reported. 
 Pay streak estimated to cover 
 12 acres. 
 
 Production of cassiterite 
 concentrate, 1909-56: 300 lb 
 from Idaho Gulch and 19,600 lb 
 from Tofty Gulch. Idaho Gulch 
 to Tofty Gulch pay streak 
 estimated to cover 36 acres. 
 157,000 lb indicated Sn 
 reserves in tailings from Miller 
 Gulch to Tofty Gulch. 
 
 Fine cassiterite abundant for 
 1 ,000 ft along creek. 
 
 Columbite and aeschymite in 
 concentrate. Production through 
 1956 was 101,875 lb cassiterite 
 concentrate Long, narrow 
 continuous pay streak 
 estimated to cover 10 acres. 2 
 pay streaks 200 ft apart in 
 upper 2,000 ft of workings. 
 
 20,282 lb cassiterite concentrate 
 recovered 1909-56. 
 
 215,445 lb cassiterite concentrate 
 produced 1909-56. Aeschymite 
 also reported. 117,800 lb Sn 
 indicated to remain in tailings 
 from Sullivan Bench and 
 Ferguson Draw. 
 
 40,300 lb cassiterite concentrate 
 recovered 1 909-56 from drift 
 mining. Lower Woodchopper 
 Creek pay streak estimated to 
 cover 73 acres. 169,400 lb 
 indicated Sn reserves in tailings 
 of Woodchopper and Deep 
 Creeks. 
 
 15-16 
 
 15-16 
 
 15-16 
 15-16 
 
 13 
 
 75 
 
 11, 19- 
 32 
 
 11, 19, 
 32 
 
 11, 19, 
 
 32, 
 
 114 
 
 11, 19, 
 
 32, 
 
 114 
 
 13, 32 
 114 
 
 11, 19, 
 
 32, 
 
 114 
 
 19 
 
 It, 19, 
 
 32, 
 
 114 
 
 11, 19 
 
 11, 19 
 
 11, 19 
 114 
 
 NA Not available. 
 
19 
 
 Table A-2. — Placer occurrences — Continued 
 
 Name and 
 lat-long location 
 
 Map 
 location 
 (fig. D 
 
 Commodities 
 (in order of 
 importance) 
 
 Ore grade 
 
 and or 
 assay data 
 
 Production 
 and or description 
 
 Refer- 
 ences 
 
 KUSKOKWIM TREND 
 
 Vmasale Mountain. 
 62-"38 N. 15759 W 
 
 Malamute Creek. 
 62°2B'K 158'OOW 
 
 Marvel Creek. 
 60'54 N. 159 30W 
 
 42 
 
 44 
 
 46 
 
 Au. Cb. Sn 
 
 Au. Sn. Hg. W. Cr 
 
 Au. Cb 
 
 Anomalously large 
 concentrations of Cb and 
 Sn reported in concentrates. 
 
 Cassiterite. cinnabar, scheelite, 
 ferberite. chromite. realgar. 
 and allanite in concentrates. 
 
 Anomalously large 
 concentrations of Cb 
 reported in concentrates. 
 
 Only Au recovered 
 
 do 
 
 do 
 
 75 
 
 13, 116 
 
 75 
 
 ALASKA RANGE TREND 
 
 Poorman Creek. 
 62 35 N. 150 49 W 
 
 52 
 
 Au. Sn. Pt 
 
 Cassiterite in concentrates. 
 
 1 1 -ft-deep Tertiary gravels on 39, 98, 
 
 lower portion of creek mined for 67 
 Au. May have most cassiterite 
 in Yentna district. 
 

 
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UNITED STATES 
 
 DEPARTMENT OF THE INTERIOR 
 
 BUREAU OF MINES 
 
 A L A S K 
 
 A 
 
 MAP E 
 
 
 60 100 
 
 150 
 
 Scale, ml 
 
 
 I983 
 
 
 LOCATION OF OCCURRENCES, 
 
 PROSPECTS, DISTRICTS, AND AREAS 
 
 CONTAINING TIN (Sn>, TANTALUM (Ta), 
 
 AND/OR COLUMBIUM (Cb) 
 
 1 Esoluk Glacier and McCall 
 
 Glacier 
 
 2 Bear Mountain prospecl Cb 
 
 3 Rapid and Porcupine Rivers area Sn, Cb 
 
 4 Unnamed occurrences Sn 
 
 5 Unnamed occurrences Sn 
 
 6 Kaluich occurrence Sn 
 
 7 Kiana occurrence 
 
 8 Gold Bench occurrence 
 
 9 Selawik Hills area 
 
 10 Ear Mountain area 
 
 11 Potato Mountain area 
 
 12 Cape Mountain area 
 
 13 Lost River Mine area 
 
 14 Black Mountain occurrence 
 
 15 Unnamed occurrence 
 
 16 Kougarok Mountain a 
 
 17 Hannum Creek occur 
 
 18 Otter Creek Mine 
 
 19 Monument Creek occurrence 
 
 20 Rocky Mountain Creek 
 
 Sn. Cb 
 
 ?1 
 
 Omilak and Foster prospects 
 
 Sn 
 
 
 ?i» 
 
 Clear and Vulcan Creeks area 
 
 Oh 
 
 Sn 
 
 23 
 
 Granite Mountain area 
 
 Cb 
 
 Sn 
 
 24 
 
 Hogatza occurrence 
 
 Sn 
 
 
 2b 
 
 Sithylemenkal area 
 
 Sn 
 
 Ta, Cb 
 
 2b 
 
 Hoi Springs plulon area 
 
 sn 
 
 
 2/ 
 
 Fort Hamlin Hills pluton area 
 
 Sn, 
 
 Cb 
 
 20 
 
 Quartz Creek prospecl 
 
 Sn 
 
 
 m 
 
 Tozimoran and Ash Creeks ares 
 
 Sn 
 
 
 3d 
 
 Mason Creek Mine 
 
 Sn 
 
 
 m 
 
 Morelock Creek and Bonanza 
 
 
 
 
 Creek prospects 
 
 Sn 
 
 
 32 
 
 Ruby mining district 
 
 Sn 
 
 
 sa 
 
 Circle mining district 
 
 Lime Peak (Rocky Mountain) 
 
 Sn 
 
 
 34 
 
 
 
 
 prospect 
 
 Sn, 
 
 3b 
 
 :a 
 
 Fairbanks mining district 
 
 Sn 
 
 
 3« 
 
 Totty tin belt 
 
 Sn 
 
 ;b 
 
 31 
 
 Cosna prospect 
 
 Sn 
 
 
 m 
 
 Win prospect 
 
 Sn 
 
 
 39 
 
 Won prospect 
 
 Sn 
 
 
 40 
 
 Mystery Mountain area 
 
 Kn 
 
 
 41 
 
 Tellda Mountain area 
 
 Sn 
 
 
 42 
 
 vinasale Mountain area 
 
 Cb 
 
 Sn 
 
 43 
 
 Beaver Mountains area 
 
 Cb 
 
 Sn 
 
 44 
 
 Malamute Creek occurrence 
 
 Kn 
 
 
 4b 
 
 Russian Mountains occurrence 
 
 Sn 
 
 
 46 
 
 Marvel Creek occurrence 
 
 Oti 
 
 
 4/ 
 
 Sheep Creek prospect 
 
 Sn 
 
 
 43 
 
 Kantishna mining district 
 
 Sn 
 
 
 49 
 
 Chulitna area 
 
 Sn 
 
 
 bO 
 
 Tsusena Creek prospect 
 
 Sn 
 
 
 b1 
 
 Boulder Creek prospect 
 
 Sn 
 
 
 bH 
 
 Yentna mining district 
 
 Sn 
 
 
 63 
 
 Tired Pup pluton area 
 
 Sn 
 
 
 b4 
 
 Valley ot Ten Thousand Smokes 
 
 
 
 
 area 
 
 Sn 
 
 
 bb 
 
 Copper Mountain occurrence 
 
 Sn 
 
 
 46' 
 
 Rude River occurrence 
 
 Sn 
 
 
 V 
 
 Tarr Inlet Knob occurrence 
 
 Sn 
 
 
 iS 
 
 Johns Hopkins inlet occurrence 
 
 Sn 
 
 
 iS 
 
 Edelweiss prospecl 
 
 Oh 
 
 
 60 
 
 Salmon Bay prospect 
 
 Ob 
 
 
 61 
 
 Bokan Mountain area 
 
 Cb 
 
 
 FIGURE 1.— Tin, tantalum, and columblum occurrences In Alaska. 
 
 IC9037