natural mineral formations containing molybdenum in quantities that make its extraction economically feasible. The reserves of molybdenum in ores in developed deposits range from a few thousand tons to millions of tons. The average molybdenum content in the ores of large deposits ranges from 0.06 to 0.30 percent, and in small deposits, from 0.5 to 1.0 percent. Molybdenum is extracted as a by-product from other ores where its content is 0.005 percent or more.
Molybdenum ores form under endogenous and exogenous conditions. Endogenous ores are related to skarn, greisen, and hydrothermal deposits. The major ore mineral in these deposits is molybdenite (MoS2), which contains 60 percent molybdenum. Copper and tungsten—and, to a lesser extent, bismuth, beryllium, and tin—are found in various proportions in molybdenum ore. In addition, rhenium is always present in molybdenite.
Molybdenum ores are spatially and genetically related to intrusive rock. Copper-molybdenum ores are related to monzonites, granodiorites, and granosyenites; monometallic molybdenum ores, to biotite-hornblende granites; and tungsten-molybdenum ores, to leucocratic subalkaline granites.
Exogenous molybdenum ores are known in coals and carbonaceous-siliceous-clay shale, as well as in solid asphalts. Here molybdenum is closely related to organic matter and is usually associated with vanadium, uranium, and germanium. The molybdenum content in such deposits is low (thousandths or hundredths of a percent). The ores of such deposits are reserves for the future.
Most mining of molybdenum ores is done in large skarn and stockwork deposits. The enrichment of molybdenum ores by flotation makes possible the production of molybdenum concentrates with a molybdenum content of up to 51 percent. The largest known deposits of molybdenum ores in the USSR are in the Armenian SSR (Kadzharan and Agarak), the Northern Caucasus (Tyrnyauz), the Uzbek SSR (Almalyk), and the Kazakh SSR (Kounrad and Boshchekul’). In other countries, molybdenum ores are found in the USA (Climax, Bingham, and Henderson), Canada (Endaco), Chile (Chuquicamata), Mexico (Cananea), China, and Australia.
The mining of molybdenum ores in capitalist and developing countries in 1970 was 84,200 tons in the USA, 25,600 tons in Canada, and 10,000 tons in Chile (in terms of molybdenum disulfide content); smaller amounts were mined in Peru, Norway, Japan, and Mexico.
REFERENCESOtsenka mestorozhdenii pri poiskakh i razvedkakh. Fasc. 19: N. A. Khrushov, Molibden. Moscow, 1961.
Pokalov, V. T. Geneticheskie tipy i poiskovye kriterii endogennykh mestorozhdenii molibdena. Moscow, 1972.
V. T. POKALOV