Silver and Gold: an Account of the Mining and Metallurgical Industry of the United States: With Reference Chiefly to the Precious MetalsJ.B. Ford, 1873 - 566 halaman |
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Halaman 41
... drift or tunnel , has long been a desideratum , and has long exercised the ingenuity of our mechanics and miners . The system of drilling by machinery used in the construction of large tun- nels , such as the Hoosac and the Mount Cenis ...
... drift or tunnel , has long been a desideratum , and has long exercised the ingenuity of our mechanics and miners . The system of drilling by machinery used in the construction of large tun- nels , such as the Hoosac and the Mount Cenis ...
Halaman 43
... drift or tunnel , at the same time , the work of a hundred men can be done in the space where only four could work by the old method of hand - drilling . In form it is com- posed of two cylinders , the shorter and larger one being ...
... drift or tunnel , at the same time , the work of a hundred men can be done in the space where only four could work by the old method of hand - drilling . In form it is com- posed of two cylinders , the shorter and larger one being ...
Halaman 63
... drift is now 1,600 feet in length on the channel , but " breasting " has not been made on more than half this distance . The gravel is brought from the " head " or " breasts " of the drifts by a car drawn by a mule to the foot of the ...
... drift is now 1,600 feet in length on the channel , but " breasting " has not been made on more than half this distance . The gravel is brought from the " head " or " breasts " of the drifts by a car drawn by a mule to the foot of the ...
Halaman 64
... drifts of the two companies are now approaching each other , one running north and the other south on the channel , and before the close of the present year the communication will be opened through the mountain under the lava crust ...
... drifts of the two companies are now approaching each other , one running north and the other south on the channel , and before the close of the present year the communication will be opened through the mountain under the lava crust ...
Halaman 66
... twenty - eight to thirty degrees . Both walls are granite , and the fissure varies in width . At the north end of the drifts the vein mat- ter is about eight feet wide and yields an average 66 MINING STATISTICS WEST OF THE ROCKY MOUNTAINS .
... twenty - eight to thirty degrees . Both walls are granite , and the fissure varies in width . At the north end of the drifts the vein mat- ter is about eight feet wide and yields an average 66 MINING STATISTICS WEST OF THE ROCKY MOUNTAINS .
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50 feet amalgam amount antimony arrastra assay average Bannack base bullion bed-rock bullion Calaveras County California CaƱon 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 metal metallurgy 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