Mine Production of Silver

Mine Production of Silver. World production of silver by region is given in Table 3. Some 900,000 metric tons are estimated to have been mined since early times. By the year 1500 world mine production was about 50 t/yr. In 1992 world production exceeded 14,900 metric tons. EoUowing the breakup of tfie Soviet Union, previously undisclosed data showed that the USSR led wodd silver production during 1979—1980 at about 1550 metric tons. During the early 1990s the production in this region exceeded 2000 t/yr. 

World production of silver increased from 7.4 miUion kg in 1964 to 9.06 million kg in 1972 and to 9.67 million kg in 1982. In 1986, 13.06 miUion kg of silver was produced globally the United States produced 1.06 million kg in 1986 but consumed 3.94 million kg. In 1990, the estimated world mine production of silver was 14.6 million kg major producers were Mexico with 17% of the total, the United Stales with 14%, Peru with 12%, the... 

Silver Manufacture - Metallurgical and Chemical l35 Table 6.1 World mine production of silver by country in 2000... 

The Gogerddan mines near Aberystwyth two or three centuries ago were very productive of silver the ore was galena. It is said that they yielded to Sir Hugh Myddleton a profit of some 25,000 a year which enabled him to pursue and complete in 1613, with... 

Lead was widely used in ancient times, dating back over 7000 years. It was often mined and produced as a co-product of silver, which was highly prized for ornamentation and jewellery and later for coinage. Lead served as a collector for silver and gold and often smelting was conducted primarily for this purpose. Lead was separated from the precious metals by oxidation in the cupellation process . 

The American cordillera extending from Alaska to BoUvia has been the most productive source of silver wherever it is associated with Tertiary age intmsive volcanic rocks, mosdy concentrated by hydrothermal action. The largest producing mine in the cordillera is at Potosi, BoUvia, where the total silver output since the 1500s is estimated at over 31,000 metric tons. 

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. 

In the Commonwealth of Independent States (CIS, formerly the USSR), nearly 50% of the CIS production comes from Ka2akhstan. Silver is produced from the lead—2inc mines at Ostkamen, Shymkent, and Leninogorsk (ca 1000 t) and also in Russia s Far East, where it is a by-product of the tin deposits near Khabarovsk, and of the copper and gold deposits in the Ural Mountains. 

Canada s most productive district is in the Canadian shield at Cobalt, Ontario. Nearly 97% of the silver values in this pre-Cambrian age ore were found as great slabs of nearly pure silver. One slab was 474 kg. The huge open-pit Kidd Creek Mine has had an aimual output of over 80 t of silver. 

U.S. silver production from 1985 to 1994 averaged 1588 t/yr. Less than one quarter of this output comes from silver mine districts, however. About half is as by-product of gold mines about one quarter comes from copper and lead—2inc mines. The silver production in Mexico from 1985 to 1994 averaged 2256 t/yr, and Pern, at the southern extremity of the cordillera, where silver is a by-product of copper and lead—2inc mines, averaged 1810 t/yr. 

Secondary Silver Recovery. The consumption of sdvei normally exceeds its mine production therefore recovery from scrapped products. ... 

Montana. These deposits consist of stibnite and other sulfide minerals containing base metals and silver or gold. Ores of the complex deposits are mined primarily for lead, copper, 2inc, or precious metals antimony is a by-product of the treatment of these ores. 

In 1996, mines in Missouri and Alaska accounted for 93% of total US. lead mine production. Domestic lead mine production decreased in 1992 and 1993 as a result of low lead, gold, and silver metal prices, but increased the following three years when several mines either expanded or reopened due to increased metal prices. Domestic lead mine production reached 436,000 metric tons in 1996 and an estimated 450,000 metric tons in 1997, which was still less than the 484,000 metric tons produced in 1990 (Larrabee 1997 Smith 1998). 

Cobalt is also found in seawater, meteorites, and other ores such as linnaeite, chloanthite, and smaltite, and traces are found mixed with the ores of silver, copper, nickel, zinc, and manganese. Cobalt ores are found in Canada and parts of Africa, but most of the cobalt used in the United States is recovered as a by-product of the mining, smelting, and refining of the ores of iron, nickel, lead, copper, and zinc. 

Platinum is the 75th most abundant element and, unlike many elements, is found in its pure elemental form in nature, as are deposits of silver and gold. Platinum is widely distributed over the Earth and is mined mainly in the Ural Mountains in Russia and in South Africa, Alaska, the western United States, Columbia in South America, and Ontario in Canada. When found in the mineral sperryhte (PtAs ), it is dissolved with aqua regia to form a precipitate called sponge that is then converted into platinum metal. It is also recovered as a by-product of nickel mining, mainly in Ontario, Canada. 

Another species of this substance, says Phillips, forms one of the principal sources of silver in the rich mines of Arqucros, in the province of Coquimbo, Chili. From its malleability and general appearance this product was for a long time thought to bo metallic silver. According to the analysis of Professor Domeyko, of the mining school of Coquimbo, this amalgam consists of silver 86-63, mercury 13 37, from which it appears to be composed of six equivalents of silver united to one of mercury, and its composition may therefore be represented by the formula Agg Ilg. 

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