. Transactions . SECTION MINE immc Division, y/jle district. COLUMBIA. The Emma Mine. 193 mainly composed of feldspar and hornblende. A few crystalsof iron sulphide are also present. Fig. 4 is from near the ore on 250 level, 40 feet north of theEmma shaft and like Fig. 1 shows limestone in the course ofconversion to ± ig. 4. Some pyroxene is present in small grains, and all the calcitewhich remains is in minute lines running through the rock. The sections are magnified 25 diameters. Mining.—Owing to the vertical position of the deposit,mining here is a much simpler problem than in mos
. Transactions . SECTION MINE immc Division, y/jle district. COLUMBIA. The Emma Mine. 193 mainly composed of feldspar and hornblende. A few crystalsof iron sulphide are also present. Fig. 4 is from near the ore on 250 level, 40 feet north of theEmma shaft and like Fig. 1 shows limestone in the course ofconversion to ± ig. 4. Some pyroxene is present in small grains, and all the calcitewhich remains is in minute lines running through the rock. The sections are magnified 25 diameters. Mining.—Owing to the vertical position of the deposit,mining here is a much simpler problem than in most of the Boun-dary mines. The shaft is a two compartment incline, angle 60degrees. Across the drifts are placed heavy stuUs supported byposts, the stulls and posts in the widest portions of the drift beingoften 30 inches in diameter. The stulls are placed 5 feet apart, and are covered with 8 to12 inch pole lagging. Chutes are provided at convenient intervals,they being at the opening 3^ to 4 feet wide by 2 to 2^ feet deep,so as to allow large rocks to pass. The ore is broken down on thetimbers to the level above, only the swell being drawn from thechutes, which swell amounts to about 40%. After the level aboveis reached the stopes can be drawn at will, and, commencing at 13 194 The Canadian Mining Institute. the p
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