Tungsten mine production

FIGURE 13.8. World tungsten mine production and demand (1975-1995) [13.7]. 

Molybdenum is also recovered as a by-product of copper and tungsten mining operations. The metal is prepared from the powder made by the hydrogen reduction of purified molybdic trioxide or ammonium molybdate. 

Mined bismuth in China is a by-product of tungsten mining operations, but most of the bismuth produced in China comes from bismuth concentrates. 

FIGURE 2.5. Cumulative mine production, reserves, and static lifetime of tungsten (1.1.1946-1.1.1978) [2.19]. 

Tungsten s economy was generally ruled by the supply/demand situation, which itself was a consequence of the world s general economic situation. Booming industry was always associated with enhanced tungsten consumption and mine production as well as with the search for new deposits. Times of general recession always showed minimum of the consumption combined with mine closures. Wars reflected situations of highest industrial activity and always maximum of consumption and prices. 

Other parameters influencing tungsten s economy are shown schematically in Fig. 13.1. The different types of stock may evidently create a confusing picture of the situation at any given time. No direct relationship exists between mine production, supply, demand, and consumption. The supply may originate from mine production, from scrap, or from stocks. The demand must not be necessarily balanced with consumption, because economic reasons may dictate a build up or decrease of intermediate stocks. 

In Fig. 13.2, the share of different countries and continents or political areas in available tungsten ore deposits is shown. In former times, the percentage of mine production showed a similar picture, but since the late 1970s the situation has changed. 

The end of the cold war had a strong worldwide impact on tungsten consumption, and consequently on mine production (see Section 13.3 for more details). 

As it can be seen in Table 13.1, that supply/demand statistics are worldwide more or less balanced. Primary tungsten supply to the MEC is illustrated in Fig. 13.7 (by suppliers). The share of China increased while die supply from the MEC decreased. The 1994 imports from CIS were additional. However, what is not at all obvious is the origin of the supply, either from stocks or from mine production. Therefore, another statistic (comparison of mine production and demand) shows a much less balanced situation (Fig. 13.8). The following short historical consideration should explain the situation between 1981 and 1996. 

Bismuth is referred to as a minor metal. It is not generally mined for its own intrinsic value, rather it is mined primarily as a by-product of lead or copper ores. In China, however, bismuth can be found ia tungsten ores. In BoHvia the metal has been mined for its own value, but this has not happened on a consistent basis over the years because fluctuations ia the bismuth price have at times made it uneconomical to recover. 

Primary Mined particularly for the molybdenum contained in the ores. In some instances, molybdenum could be the only valuable metal recovered from the ore. The Questa deposit in New Mexico is mined exclusively for molybdenum content. In other deposits molybdenum may be the main product recovered together with one or more products. In these deposits the molybdenum content alone would allow for a profitable operation. The ore at the Climax mine in Colorado is of this type. Currently, monazite, pyrite, tin, and tungsten are recovered from the ore none of these by-products exists singly nor together in sufficient quantity so that the ore could be mined profitably merely for the extraction of one or all of these by-products. 

By-product of tungsten ores The Pine Creek mine in California is the only operation that is having such reserves. 

World molybdenum production has increased from about 90 metric tons in 1900 — half from Australia and Norway, half from the United States — to 136 tons in 1906, 1364 in 1932 (an order of magnitude increase in 26 years), 10,909 in 1946, and 91,000 tons in 1973. Through the years, molybdenum has been produced in about 30 countries. In 1973, about 60% of the worldwide production was from the United States, 15% from Canada, 15% from the U.S.S.R. and China combined, and 10% from other nations — Chile, Japan, Korea, Norway, and Mexico (King et al. 1973). By 1979, the United States produced about 62% of the world production of 103,000 metric tons, and exported about half, chiefly to western Europe and Japan other major producers in 1979 were Canada, Chile, and the U.S.S.R. (Kummer 1980). In the United States, only three mines in Colorado account for almost 70% of domestic production. Other active molybdenum mining sites in North America are in Arizona, Nevada, New Mexico, Utah, and California molybdenum reserves have also been proven in Idaho, Alaska, Pennsylvania, and British Columbia (Kummer 1980). About 65% of domestic molybdenum is recovered from ores rich in molybdenum the rest is a byproduct from ores of copper, tungsten, and uranium (Chappell et al. 1979). 

The loss of tungsten in the production of ferrotungsten has been estimated by the Bureau of Mines as between 14 and 25 per cent. These losses are largely mechanical, but are partly due to incomplete reactions. 

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