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 99
Stran 82
... feet , then supposing that the ground below was barren , they were deserted , but were again opened up and worked to a depth of 40 to 50 feet in 1869.3 In 1863 , the placers of Horse Prairie Creek were discovered , and two years later ...
... feet , then supposing that the ground below was barren , they were deserted , but were again opened up and worked to a depth of 40 to 50 feet in 1869.3 In 1863 , the placers of Horse Prairie Creek were discovered , and two years later ...
Stran 175
... feet wide , at the Mexican 150 feet and at the Ready Bullion it has again increased to 300 feet ; these figures , however , include large horses , and in places a system of parallel slate divisions . Following the intrusion of syenite ...
... feet wide , at the Mexican 150 feet and at the Ready Bullion it has again increased to 300 feet ; these figures , however , include large horses , and in places a system of parallel slate divisions . Following the intrusion of syenite ...
Stran 182
... feet in thickness have been opened to a depth of 300 feet and over . The ore carries both gold and silver , is quartzitic and occasionally ferruginized . The silver occurs as chloride , bromide , sulphide and iodide , while gold is ...
... feet in thickness have been opened to a depth of 300 feet and over . The ore carries both gold and silver , is quartzitic and occasionally ferruginized . The silver occurs as chloride , bromide , sulphide and iodide , while gold is ...
Stran 183
... feet north and south by 450 feet east and west . This ore belt extends for a distance of 12 to 18 miles and is considerably cut up by intrusions of volcanic rock . Small ore- bodies occur at intervals along the belt . The ores have ...
... feet north and south by 450 feet east and west . This ore belt extends for a distance of 12 to 18 miles and is considerably cut up by intrusions of volcanic rock . Small ore- bodies occur at intervals along the belt . The ores have ...
Stran 185
... feet in width . Widths of from 10 to 15 feet are found in the veins of Mariposa and Tuolumne counties , but they are rather limited in horizontal extent and probably do not extend deeper than 10,000 feet . The common form of gangue is ...
... feet in width . Widths of from 10 to 15 feet are found in the veins of Mariposa and Tuolumne counties , but they are rather limited in horizontal extent and probably do not extend deeper than 10,000 feet . The common form of gangue is ...
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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