Silver resources

Deposits. Selenium forms natural compounds with 16 other elements. It is a main constituent of 39 mineral species and a minor component of 37 others, chiefly sulfides. The minerals are finely disseminated and do not form a selenium ore. Because there are no deposits that can be worked for selenium recovery alone, there are no mine reserves. Nevertheless, the 1995 world reserves, chiefly in nonferrous metals sulfide deposits, are ca 70,000 metric tons and total resources are ca 130,000 t (24). The principal resources of the world are in the base metal sulfide deposits that are mined primarily for copper, zinc, nickel, and silver, and to a lesser extent, lead and mercury, where selenium recovery is secondary. 

Mexico, the world s leading producer of silver since the Spanish conquest, obtains virtually its entire silver production from lead—2inc mines in the central cordillera. Mexico retained its dominance in silver production until the discovery of the Comstock Lode in Nevada in 1859. Discoveries in Colorado, Ari2ona, and Montana placed the United States as the world s top silver producer from 1871 until 1900. As these mines played out, Mexico s vast resources returned it to its former position of dominance. 

Resources. World resources of silver are estimated to be about half a million tons. However, only about 250,000 metric tons are considered economically recoverable reserves. These are associated with ores of copper, gold, lead, and 2inc, and extraction depends on the economic recovery of those metals. Canada and the CIS vie for the greatest reserves of silver in the ground. 

T. P. Mohide, Silver, Ontario Ministry of Mineral Resources, Toronto, Canada, 1985. 

Like selenium, tellurium minerals, although widely disseminated, do not form ore bodies. Hence, there are no deposits that can be mined for tellurium alone, and there are no formally stated reserves. Large resources however, are present in the base-metal sulfide deposits mined for copper, nickel, gold, silver, and lead, where the recovery of tellurium, like that of selenium, is incidental. 

Continental Silver Bow, Mont. Montana Resources Inc. copper—molybdenum ore, concentrated 50... 

Viebrock, H. J., (ed.), "Fiscal Year 1980 Summary Report of NOAA Meteorology Laboratory Support to the Environmental Protection Agency." National Oceanic and Atmospheric Administration Tech. Memo. ERL ARL-107. Air Resources Laboratories, Silver Spring, MD, 1981. 

Berger, B.R. (1983a) Epithermal gold-silver quartz-adularia type. In Cox, D.P. (ed.), GEOMINAS Mineral Resource Assessment of Columbia — Ore Deposit Models, U.S. Geological Survey. Open-File Report, 83, V. 23, 39. 

Ibaraki, K. and Suzuki, R. (1993) Gold-silver quartz-adularia veins of the Main, Yamada and Sanjin deposits, Hishikari gold mine a comparative study of their geology and ore deposits. Resource Geology Special Issue, 14, 1-11. 

Miyashita, A. (1995) Were the epithermal gold-silver deposits in the Hokusatsu region formed in association with cauldrons Resource Geology, 45, 313-321 (in Japanese). 

Ohta, E. (1992) Silver mineralization at the Toyoha mine, Hokkaido, Japan. Resource Geology, 42, 19-32. 

Cadmium (Cd) anode cells are at present manufactured based on nickel-cadmium, silver-cadmium, and mercury-cadmium couples. Thus wastewater streams from cadmium-based battery industries carry toxic metals cadmium, nickel, silver, and mercury, of which Cd is regarded the most hazardous. It is estimated that globally, manufacturing activities add about 3-10 times more Cd to the atmosphere than from natural resources such as forest fire and volcanic emissions. As a matter of fact, some studies have shown that NiCd batteries contribute almost 80% of cadmium to the environment,4,23 while the atmosphere is contaminated when cadmium is smelted and released as vapor into the atmosphere4 Consequently, terrestrial, aquatic, and atmospheric environments become contaminated with cadmium and remain reservoirs for human cadmium poisoning. 

Keeling, C. D., The Influence of Mauna Loa Observatory on the Development of Atmospheric C02 Research, 1978, J. M. Miller, ed., N0AA Special Report, Air Resources Laboratory, Silver Spring. 

Proposed silver criteria for the protection of natural resources and human health... 

Table 7.8 Proposed Silver Criteria for the Protection of Natural Resources and Human Health... 

Resource, Criterion, and Other Variables Effective Silver Concentration Referenceb... 

Using Resources Use resources such as the CRC Handbook of Chemistry and Physics, the Merck Index, or the Internet to determine the colors of silver metal and copper nitrate in water. Compare this information with your observations of the reactants and products in step 6. 

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