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 92
Stran 23
... lower California have had access to gold as far back as we have any record of them , which they have used as a medium of exchange in barter , also as ornaments some exceed- ingly rare specimens of virgin gold having been found among ...
... lower California have had access to gold as far back as we have any record of them , which they have used as a medium of exchange in barter , also as ornaments some exceed- ingly rare specimens of virgin gold having been found among ...
Stran 69
... lower- grade ores were being worked . Probably the most interesting event of 1903 was the starting and completion of the drainage adit , which made connection with the El Paso mine on September 6 , 1903. This tunnel proved conclusively ...
... lower- grade ores were being worked . Probably the most interesting event of 1903 was the starting and completion of the drainage adit , which made connection with the El Paso mine on September 6 , 1903. This tunnel proved conclusively ...
Stran 93
... lower Ammonoosuc River as early as 1866.2 The Eaton lode was discovered in 1826 , 3 and yielded lead - silver ore . The Ammonoosuc gold field has been described by Professor C. H. Hitchcock as auriferous slates and schists occurring ...
... lower Ammonoosuc River as early as 1866.2 The Eaton lode was discovered in 1826 , 3 and yielded lead - silver ore . The Ammonoosuc gold field has been described by Professor C. H. Hitchcock as auriferous slates and schists occurring ...
Stran 100
... lower they are , and gold is found very near the surface in the higher and hilly parts , while , on the contrary , in the great deposits of the lower parts of the valley the auriferous strata are covered by sterile masses . Near the ...
... lower they are , and gold is found very near the surface in the higher and hilly parts , while , on the contrary , in the great deposits of the lower parts of the valley the auriferous strata are covered by sterile masses . Near the ...
Stran 152
... lower point , having perhaps gone deeper than the vent by a syphonic movement around an impervious barrier . With increasing depth within the earth the deep waters meet zones of slowly increasing temperature , and hence conditions of ...
... lower point , having perhaps gone deeper than the vent by a syphonic movement around an impervious barrier . With increasing depth within the earth the deep waters meet zones of slowly increasing temperature , and hence conditions of ...
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Alaska amalgamation andesite argentiferous assay auriferous average bed-rock blende bornite calcite California Carolina cent chalcopyrite chloride chlorination Colorado Comstock lode concentration 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 gneiss gold and silver gold production Gold-bearing granite gravel gray copper Gulch Hill hydraulic Ibid Idaho inches iron Jour lead limestone located mercury method Mexico mill Mineral Industry Mineral Resources Mines and Minerals Montana Mountain Nevada North occur operations ore-bodies ounces output oxide placer mines placers porphyry precious metals Press probably production of gold pyrite pyrrhotite quantities quartz quartz-veins quartzites Rept rhyolite River rocks schists shaft siliceous silver production Silver-bearing slate sluices smelting solution South stamps stope sulphides sulphurets surface TABLE tellurides tellurium tetrahedrite timber tion tons Total tunnel Utah yield zinc