Transactions . ton capacity, with Hyatt roller-bearing wheels. Five-ton bar frame Westinghouse electric locomotives areused, operating at 260 volts from an overhead trolley wire. The standardtrack gage on all levels, except the 700-ft. main railroad tunnel level,for both hand and electric tramming is 20 in. ( cm.). Hand trammingtracks use 16-lb. ( kg.) rails and electric tracks use 40-lb. ()rails. 398 GEOLOGY AND MINING METHODS AT PILARES MINE The mine employs about 1300 men underground and 300 men on thesurface. All labor is Mexican. The only Americans are the divisionforemen
Transactions . ton capacity, with Hyatt roller-bearing wheels. Five-ton bar frame Westinghouse electric locomotives areused, operating at 260 volts from an overhead trolley wire. The standardtrack gage on all levels, except the 700-ft. main railroad tunnel level,for both hand and electric tramming is 20 in. ( cm.). Hand trammingtracks use 16-lb. ( kg.) rails and electric tracks use 40-lb. ()rails. 398 GEOLOGY AND MINING METHODS AT PILARES MINE The mine employs about 1300 men underground and 300 men on thesurface. All labor is Mexican. The only Americans are the divisionforemen, engineers, and heads of departmc^nts. All developnient work,mucking, and tramming is done by contract at so much per foot or percar. A considerable number of the stopes are also operated on con-tract. In drifting and cross-cutting, Leyncr & Waugh 60 Drc^adnoughtand Waugh Turbo machines are used, mounted on 8-ft. () standard drive is ft. by 5 ft. wide for machine work, and 7 ft. high. Fig. 7.—Esperanza shaft head-frame with compressor house and hoist house in background. by 5 ft. wide for hand work. The standard drift round is shown in theillustration. Stoping is done with 16-V Waugh and CC-11 Ingersoll-Rand stopers. The men running stoping drills are paid by the foot ofdrill hole put in per shift. Storing Methods We haye in operation the following methods of stoping orebodies:Hard ore in ground that stands exceptionally well is mined by the flatcut-and-fill method and an incline shrinkage-and-fill method. Cut-and-fill Method.—The flat cut-and-fill method, shown in Fig. 8, hasbeen the standard method of Pilares for several years and is the method W. ROGERS WADE AND ALFRED WANDTKE 399 that, at present, produces the largest percentage of the ore. The groundstands exceptionally well in the majority of the orebodies. Some of theseflat cut-and-fill stopes often reach very large dimensions, as, for example,the 646 stope, which is 60 ft. ( m.) wide by
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
