STATUS OF MINERAL RESOURCE INFORMATION FOR THE CROW INDIAN RESERVATION, MONTANA By W. J. Mapel R. N. Roby J. C. Sarnecki Michael Sokaski B. F. Bohor George McIntyre U. S. Geological Survey U. S. Bureau of Mines Administrative report BIA-7 1975 CONTENTS SUMMARY AND RECOMMENDATIONS ........................................... 1 INTRODUCTION ................................................................ 1 PRESENT STUDY ............................................................... 2 GEOLOGY ..................................................................... 2 Setting ................................................................... 2 Rock Units ................................................................ 2 Structure.................................................................. 7 Folds............................................................... 7 Bighorn and Pryor Uplifts ........................................ 7 Subsidiary Folds................................................ 8 Faults .............................................................. 8 MINERAL RESOURCES .......................................................... 9 General ................................................................... 9 Energy ................................................................... 9 Coal ............................................................... 9 General ....................................................... 9 Coal in the Cloverly Formation ................................... 10 Coal in the Parkman Sandstone ................................... 10 Coal in Nonmarine Equivalents of the Bearpaw Shale ................. 10 Coal in the Hell Creek Formation ................................. 10 Coal in the Fort Union Formation ................................. 11 Tullock and Lebo Shale Members ........................... 11 Tongue River Member .................................... 11 Roland Bed....................................... 12 Smith Bed........................................ 12 Anderson Bed..................................... 12 Dietz Bed ........................................ 12 Canyon Bed ...................................... 13 Wall Bed ........................................ 13 Rosebud bed ...................................... 13 McKay bed ....................................... 14 Robinson bed ..................................... 14 Burley bed ....................................... 14 Potential Resources ............................................ 14 Reserves ..................................................... 14 General ................................................ 14 North of the Reservation .................................. 15 Southeast of the Reservation ............................... 15 On the Reservation....................................... 16 Coal Characteristics ............................................ 17 Coal Preparation............................................... 17 Mining Methods ............................................... 18 Surface Mining .......................................... 18 Underground Mining ..................................... 19 Markets and Uses .............................................. 20 Electrical Power Generation ............................... 20 Metallurgical Applications................................. 20 Gasification ............................................ 20 Synthetic Liquid Fuels .................................... 21 Transportation ................................................ 22 General ................................................ 22 Unit Trains ............................................. 22 Slurry Pipeline .......................................... 22 Electrical Power System .................................. 23 Byproducts ....................................... 23 Synthetic fuels .......................................... 24 Energy Parks ........................................... 24 Environmental Aspects ......................................... 24 Surface Rehabilitation .................................... 24 Aquifers ......................................... 26 Emissions ........................................ 26 Recommendations ............................................. 27 Petroleum and Natural Gas ............................................ 28 General ...................................................... 28 Geologic Setting and Controls .................................... 28 Potential Resources ............................................ 29 History and Production ......................................... 32 Soap Creek Oil Field ..................................... 32 Lodge Grass Oil Field .................................... 32 Hardin Gas Field ........................................ 34 Ash Creek Oil Field ...................................... 36 Snyder Oil Field ......................................... 38 Transportation and Markets ...................................... 39 Environmental Aspects ......................................... 39 Uranium ........................................................... 40 Geologic Setting and Controls .................................... 40 Occurrences on Reservation...................................... 41 NONMETALLIC MINERAL RESOURCES .......................................... 42 Bentonite ................................................................ 42 General ............................................................ 42 Geologic Setting and Controls .......................................... 44 Potential Resources .................................................. 45 Characteristics of Reservation Bentonites ................................. 45 Processing, Marketing, and Transportation ............................... 45 Recommendations ................................................... 46 Claystone and Shale ........................................................ 46 General ............................................................ 46 Geologic Setting and Controls .......................................... 47 Potential Resources .................................................. 48 Processing, Transportation, and Marketing ................................ 48 Gypsum ................................................................. 48 Limestone And Dolomite .................................................... 49 General ............................................................ 49 Production and Potential .............................................. 49 Sand and Gravel ........................................................... 50 General ............................................................ 50 Potential Resources .................................................. 50 Pumicite ................................................................. 51 General ............................................................ 51 Potential Resources .................................................. 51 Transportation and Marketing .......................................... 53 Building Stone ............................................................ 53 Silica Sand ............................................................... 54 Clinker .................................................................. 55 METALLIC MINERAL RESOURCES .............................................. 55 Gold and Copper .......................................................... 55 MINERAL LEASING AND PROSPECTING REGULATIONS ........................... 55 RECOMMENDATIONS FOR FURTHER WORK ..................................... 56 REFERENCES ................................................................. 57 Status of Mineral Resource Information For The Crow Indian Reservation, Montana W. J. Mapel, R. N. Roby, J. C. Sarnecki, Michael Sokaski, B. F. Bohor, and George McIntyre SUMMARY AND RECOMMENDATIONS the northern edge of the reservation, and the Montana-Wyoming border forms much of the The minerals of economic interest on the Crow southern edge. Indian Reservation include coal, petroleum, natural The northern ends of the Bighorn and Pryor gas, bentonite, claystone and shale, pumice, lime­ Mountains extend from areas farther south into the stone, gypsum, silica sand, building stone and southwestern part of the reservation where they uranium. Of these, coal has the greatest potential. form a large area of steep-walled canyons and high The northeastern and southeastern parts of the mountain slopes. Rolling grass-covered hills and reservation have been explored for coal by private broad valleys flank the mountains on the north and companies; additional work by the U.S. Geological northeast and make up the greatest part of the Survey or the U.S. Bureau of Mines is not war­ reservation. The Wolf and Rosebud Mountains ranted. form an elevated, highly dissected area along the The Crow Reserve Area is unexplored but east side of the reservation. The Bighorn River, contains potentially valuable coal deposits. Recom­ which flows generally north-eastward, and its large mended future work includes geologic mapping tributary, the north-flowing Little Bighorn River, augmented by drilling 10 to 15 holes per township cross the reservation, joining at Hardin, and are the to depths of 200 to 500 feet. major drainage ways. Elevations range from about The Powder River Basin including the Crow 9,000 feet in the Bighorn Mountains to about 2,900 Reservation is a major oil producing region. How­ feet at the confluence of the Bighorn and Little ever, most of the production has come from the Bighorn