America, North mine production

Table 9. United States, Canada, North America, South America, and World Mine Production, 10001...

In the U nited States, Arizona is the largest producer of copper, followed by U tab. New Mexico, Nevada and Montana. Many of the deposits in North America are, however, of a high-cost type with low copper contents. Because of this, more interest has been devoted to deposits in South America, China and Indonesia, countries that have shown the greatest increases in copper mine production in recent years. Annual production in the United States has decreased by 25% since 1996 owing to high production costs, falling copper prices and a weak demand, but the country is still second among the producer countries. 

Early demand for chlorine centered on textile bleaching, and chlorine generated through the electrolytic decomposition of salt (NaCl) sufficed. Sodium hydroxide was produced by the lime—soda reaction, using sodium carbonate readily available from the Solvay process. Increased demand for chlorine for PVC manufacture led to the production of chlorine and sodium hydroxide as coproducts. Solution mining of salt and the avadabiHty of asbestos resulted in the dominance of the diaphragm process in North America, whereas soHd salt and mercury avadabiHty led to the dominance of the mercury process in Europe. Japan imported its salt in soHd form and, until the development of the membrane process, also favored the mercury ceU for production. 

The demand for gas is highly seasonal. Thus pipeline companies economi2e by si2ing production faciUties to accommodate less than the system s maximum wintertime demand. Underground storage faciUties are used to meet seasonal and daily demand peaks. In North America, gas is stored in three main types of underground formations depleted oil or gas fields, aquifers that originally contained water, and caverns formed by salt domes or mines. 

Fig. 1. Principal salt deposits and dry salt production sites in North America, where H represents the salt deposits and D, x, and Q correspond to evaporated, rock, and solar production sites, respectively. Sites in Canada, Hsted by company name (location), are Alberta, , Canadian (Lindberg) Saskatchewan, , Sifto/Namsco (Unity) and Canadian (BeUe Plaine) Ontario, and x, Sifto/Namsco (Goderich) , Canadian (Windsor) x, Canadian (Ojibway) New Bmnswick, x. Potash Corp. of Saskatchewan (Sussex) and Nova Scotia, and x, Canadian (Pugwash) and Mines Seleine (Quebec), and,...

The exploration, evaluation, and development of zinc and lead ore bodies in North and Central America are discussed in Ref. 12. A survey of world zinc production in Ref. 13 gives all operating mines and mills, and their methods, production, and chemical analysis of the products zinc smelters are included. 

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 chief mined ore of titanium is ilmenite (iron titanium oxide, FeTiC>3) and it occurs as vast deposits of sand in Western Australia, Canada and the Ukraine. Large deposits of rutile (titanium dioxide, TiO ) are known in North America, and South Africa. World production of the metal itself is around 90,000 tonnes per year, small compared to titanium dioxide production which is 4.3 million tonnes per year. Reserves of titanium amount to more than 600 million tonnes and while there is an abundance of this element it is extremely costly because it has to be extracted by a complicated process, and yet it could be so much more useful if it was cheaply available. 

World production of PR in 1974 was approximately 110 Tg, having more than doubled during the past decade (FAO, 1976, p. 74). Principal world reserves are now mined in North Africa, North America, and the Kola Peninsula in the U.S.S.R. Minable reserves are scattered widely throughout the world. New deposits of PR are currently being discovered, notably in South America and in India. 

Diatomaceous earth or kieselguhr (p. 342) is mined by open-cast methods on a very substantial scale, particularly in Europe and North America, which respectively account for 59% and 19% of the world production (1.8 million tonnes in 1977). The principal use is in filtration plants, aitd this accotinis for about 60% of the supply a further 20% is used in abrasives, fillers, light-rveight aggregates and insulation material, and the remainder is used as an inert carrier, coaling agent or in the manufacture of pozzolan. 

---