Bulletin of the American Institute of Mining Engineers, Edição 81

American Institute Asst average beds bituminous coals Bldg Bolivia Bolivian Tin Bull Mountain Butte meeting carbon cent Change drill CHARLES Coal Field coal-bearing Colo compressed air compressor contains Crucible steel cylinders deposits diagram District efficiency electric EMMONS Engr exhaust valves formation fuel furnace Geological hammer drill heating value hoist hole inches Institute of Mining iron Jackhamer JAMES GAYLEY JOHN Judith River formation lever Lewistown lignite limestone load mean effective pressure metal Mexico miles Milk River mills mineral Mining Engineer Mont Montana motor operated Ore-Deposits oxides oxygen P. O. Box paper piston plant Porphyry Present position pressure production Red Lodge rock drill rope sample sandstone School of Mines Secretary shaft shale Southern Cross speed spigot steam steel stoper stroke sub-bituminous coal Supt Survey Bull tachograph Test Teton county thickness tons U. S. Geol veins workable coal York