. Transactions. of mining. The veinis almost vertical; its average width is 15 in. (38 cm.), seldom less than 12or more than 24 in. thick; the west wall is smooth, hard, and firm, withquartz sometimes frozen to it; the east wall is less well defined, decomposi-tion having extended into it to a depth of a few inches to two or threefeet; a sliding movement has occurred in the east side of the vein, and atsome points a considerable amount of gouge is found, containing piecesof vein matter. J. V. N. DORR AND L. D. DOUGAN 81 When planning a method of mining, stripping (resuing) was consid-ered, the
. Transactions. of mining. The veinis almost vertical; its average width is 15 in. (38 cm.), seldom less than 12or more than 24 in. thick; the west wall is smooth, hard, and firm, withquartz sometimes frozen to it; the east wall is less well defined, decomposi-tion having extended into it to a depth of a few inches to two or threefeet; a sliding movement has occurred in the east side of the vein, and atsome points a considerable amount of gouge is found, containing piecesof vein matter. J. V. N. DORR AND L. D. DOUGAN 81 When planning a method of mining, stripping (resuing) was consid-ered, the idea being to mine the east wall as narrow as possible, use it forfilling, break the ore away from the west wall, and run it all out. Thevein, however, was too brittle in many places to permit this; all of thequartz in the gouge would have been lost, as well as much of the veinproper. The advantages of this method—the small amount of high-grade ore to be milled, and the smaller plant to be erected—were more. Fig. 2.—A stope between the 450 and GOO-ft. level. than offset b} the greater cost of mining and the inevitable losses. Stop-ing the ore with some waste, as little as possible, required a plant of 25to 50 per cent, greater capacity, and involved a small increase in powerand supplies consumed, but this method permitted the recovery of allof the ore, and it was thought that the increased milling expenses wouldbe less than the loss by any selective method of mining. Overhead stoping was adopted, enough ore being drawn daily tomaintain proper working room above the broken ore. No sorting wasattempted in the stopes. In spite of the fact that the stopes were almost 82 ELKO PRINCE MINE AND MILL vertical, and that one wall was hard and smooth, the ore would occasion-ally hang and cause trouble. After a time, it was found that if a littleore was drawn daily from every shoot, and the broken ore was not per-mitted to remain at rest for a whole day, it would remain loose enough
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
