MINING METHODS & COSTS AT METAL MINES OF UNITED STATES By Wright 1931 IC 6503

Description

Offered here for sale is a good complete copy of
MINING METHODS & COSTS AT METAL MINES OF THE UNITED STATES by Charles Will Wright. DC: Bureau of Mines Information Circular 6503, June 1931. 10 1/2" X 8", pp 39 with 34 pp of figures; stapled self wrappers, 3 hole punched. A few tape repairs, previous owner's name inked at top of title page else good and complete. This is a well-illustrated compilation of data for United States metal mines describing open-stope methods, shrinkage methods, cut-and-fill methods, square-set and stull-set stoping methods, caved-stope methods, sublevel caving, top slicing, block caving methods. Also includes consumption of labor, power and explosives, with average costs per ton mined by each method. Profusely illustrated and quite scarce.
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