Ontario Sessional Papers, 1913, . saved, and theactual drilling time is thus increased. 4. A greater footage of drilling is even claimed for the smaller machine ina given length of drilling time. 5. Fewer holes can sometimes he used to break a round, by drilling a fewholes at a time, and then blasting. Advantage can thus Ije taken of any pecul-iarities in tlie breaking of the rock. If this method were tried with the heaviermachines, too much tijue would be consumed in setting up and tearing down. G. Small (•oiisum])tif)n of compressed air. In the harder ground and particularly in the
Ontario Sessional Papers, 1913, . saved, and theactual drilling time is thus increased. 4. A greater footage of drilling is even claimed for the smaller machine ina given length of drilling time. 5. Fewer holes can sometimes he used to break a round, by drilling a fewholes at a time, and then blasting. Advantage can thus Ije taken of any pecul-iarities in tlie breaking of the rock. If this method were tried with the heaviermachines, too much tijue would be consumed in setting up and tearing down. G. Small (•oiisum])tif)n of compressed air. In the harder ground and particularly in the solid (|uartz the piston diill isstill used for sinking on account of the large number of steel breakages (duedoubtless to crystallization) and the consequent loss of holes. Timbering employed is very simple. Square sets are used in ilic and lagging are placed in the stope aliove the drifts and the ore is brokendown onto the timber by overhand stoping. AVork is carried \\\) on tho broken i9i: MINING ENGINEER-S l^EPOUT, 11. 12 T. AXD X. 0. EAILWAY Xo. 70 ore^ only sufficient being drawn off below through chutes to keep the broken rockfar enough away from the back to allow work to proceed. At the Dome Mine a different method of mining is adopted as described underthe mine heading. Millbig: Most of the ore on the surface was free-milling, but as the workings wentdown the gold was found to be more closely associated with the sulphides andsimple amalgamation had to be augmented by cyanidation. Primary grinding of the ore is performed by stamps in all cases, except inthe Yipond mill, where rolls are employed to follow the crushers. The Hollinger mill is a cyanide plant, while at the Dome preliminary amal-gamation is employed before cyanidation. By the use of coarse screens the stampduty is run up to 10 tons or over per 24 hours. Poiver: Two hydro-electric power plants belonging to the Xorthern Canada PowerCompany have been installed on the Mattagami Eiver to supply p
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Keywords: ., bookauthorontariol, bookcentury1900, bookdecade1910, bookyear1913
