Silver and Gold: An Account of the Mining and Metallurgical Industries of the United States |
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الصفحة 87
... stopes on these levels , we will be able to get out sufficient ledge - rock to keep the mills running ; until then we will be obliged to take out considerable bowlder - rock to keep up the supply . The entire mine and machinery ( as is ...
... stopes on these levels , we will be able to get out sufficient ledge - rock to keep the mills running ; until then we will be obliged to take out considerable bowlder - rock to keep up the supply . The entire mine and machinery ( as is ...
الصفحة 128
... stopes through , as there are sometimes small bunches of quartz found within those areas rich enough to pay for the work . The free gold in the quartz is sometimes though not everywhere visible . The sulphuret or pyrites , with which ...
... stopes through , as there are sometimes small bunches of quartz found within those areas rich enough to pay for the work . The free gold in the quartz is sometimes though not everywhere visible . The sulphuret or pyrites , with which ...
الصفحة 140
... stopes , and as soon as it was cleared an accident happened to the flume , which cut off the water just as the rich rock was being milled . The average yield per ton for the six months , however , compares favorably with that of ...
... stopes , and as soon as it was cleared an accident happened to the flume , which cut off the water just as the rich rock was being milled . The average yield per ton for the six months , however , compares favorably with that of ...
الصفحة 148
... stopes where the air from the tunnel would not penetrate . According to natural laws as at present understood and received , the air entering the proposed tunnel would pass through it and up the shafts of the mines by the annoyance ...
... stopes where the air from the tunnel would not penetrate . According to natural laws as at present understood and received , the air entering the proposed tunnel would pass through it and up the shafts of the mines by the annoyance ...
الصفحة 149
... stopes and drifts not in the line of such direct transit . Hence the necessity which is assumed for a continuance of mechanical ventilation for certain portions of the mines after the completion of the tunnel . And here it may be proper ...
... stopes and drifts not in the line of such direct transit . Hence the necessity which is assumed for a continuance of mechanical ventilation for certain portions of the mines after the completion of the tunnel . And here it may be proper ...
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50 feet amalgam amount antimony arrastra assay average Bannack base bullion bed-rock bullion Calaveras County California Cañon carbonate cent chemical claim coal commenced company's contains copper cost County course Creek Cupellation December deposits depth developed district ditch drift drill east El Dorado County engine erected Eureka expense extracted feet deep feet in length feet long feet wide furnace galena gangue gold Gold Hill gravel ground Gulch Hill hundred hydraulic inches incline iron labor lead ledge limestone located lode metallurgy metals miles mill miners Mining Company months nearly Nevada opened operations ounces owners placer mines pounds present Professor prospecting quantity quartz quartzite rich River rock San Francisco silver slag slate smelting smelting-works stamps stopes sulphurets sunk supply surface Table Mountain tailings thick tion tons Total tunnel Tuolumne County tuyeres Valley vein width yield