Gold and Silver: Comprising an Economic History of Mining in the United States, the Geographical and Geological Occurrence of the Precious Metals, with Their Mineralogical Associations, History and Description of Methods of Mining and Extraction of Values, and a Detailed Discussion of the Production of Gold and Silver in the World and the United StatesJ. Wiley & Sons, 1908 - 727 strani |
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Zadetki 1–5 od 63
Stran 23
... stone wall was encoun- tered , which for some purpose had been built up from bed - rock , and must undoubtedly have required some engineering skill . However , this work must either have been carried on prior to the advent of the ...
... stone wall was encoun- tered , which for some purpose had been built up from bed - rock , and must undoubtedly have required some engineering skill . However , this work must either have been carried on prior to the advent of the ...
Stran 55
... bed - rock . On pounding it with a stone he found it malleable and suspected that it was gold . With him at the time was a laborer ( Peter Wimmer ) who subjected it to a still further and more conclusive test by boiling it in strong lye ...
... bed - rock . On pounding it with a stone he found it malleable and suspected that it was gold . With him at the time was a laborer ( Peter Wimmer ) who subjected it to a still further and more conclusive test by boiling it in strong lye ...
Stran 217
... bedding - planes , carry silver and lead , while the fissures of the north ... bed of limestone ( " short lime " ) below . The ore is galena and blende.2 ... rock of granite and 1 Eng . and Min . Jour . , Vol . 54 , p . 174 . 2 Min ...
... bedding - planes , carry silver and lead , while the fissures of the north ... bed of limestone ( " short lime " ) below . The ore is galena and blende.2 ... rock of granite and 1 Eng . and Min . Jour . , Vol . 54 , p . 174 . 2 Min ...
Stran 223
... bed of quartz , but not in workable quanti- ties . Probably the most important geologically is that at Middle- town ... rock begins with Rabun and Habersham counties in the northeastern part of the state and extends southwestward to the ...
... bed of quartz , but not in workable quanti- ties . Probably the most important geologically is that at Middle- town ... rock begins with Rabun and Habersham counties in the northeastern part of the state and extends southwestward to the ...
Stran 290
... rock which find their way into them that find lodgment , the finer and lighter particles being carried down - stream ... bed of the stream , while the gangue passes on . It has been observed that coarse gold tends to be concentrated on soft ...
... rock which find their way into them that find lodgment , the finer and lighter particles being carried down - stream ... bed of the stream , while the gangue passes on . It has been observed that coarse gold tends to be concentrated on soft ...
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Alaska amalgamation andesite argentiferous assay auriferous average bed-rock blende calcite California Carolina cent chalcopyrite chlorination Colorado Comstock lode considerable copper country-rock County Cripple Creek cyanide cyanide process Deep Mines deposits depth diorite discovered discovery district dollars drift employed extraction feet free-gold furnace galena gangue gold and silver gold production gold-bearing granite gravel gray copper Gulch Hill hydraulic Ibid Idaho igneous rocks inches iron Jour lead limestone located mercury method Mexico mill Mineral Industry Mineral Resources Mines and Minerals Montana Mountain Nevada North North Carolina occur operations ore-bodies ounces output oxide placer mines placers porphyry precious metals Press probably production of gold pyrite quantities quartz quartz-veins Rept River roasting rocks schists shaft silver production Silver-bearing slate sluices smelting solution South stamps stope sulphides sulphurets surface TABLE tellurides tellurium tetrahedrite timber tion tons Total tunnel usually Utah veins width yield zinc