Copperbelt of Central Africa

a zone of sheet deposits of copper ores on the Zambia-Zaire border, extending in a northwesterly direction for 160 km, with a width of up to 50 km. The Copperbelt continues into Katanga, where numerous deposits of copper, cobalt, and uranium occur. The first copper mine was opened in the beginning of the 20th century, and intensive mining of ore began in the late 1920’s. The chief deposits—Chililabombwe, Nchanga, Nkana, Roan Antelope, and Mufulira (in Zambia) and Kipushi, Kambove, Musonoi, Ruwe, Dikuluwe (Kolwezi), and Musoshi (in Zaire)—form two parallel series separated by a distance of 25-30 km. Before 1960, 7.5 million tons of copper and 25,000 tons of cobalt were smelted here. In 1972 total copper reserves in the deposits of Zambia and Zaire were estimated at 90 million tons, with an average copper content of 3.3-4 percent. Annually, 1.15 million tons of metal were being produced.

Most of the copper ore is found in Upper Proterozoic sedimentary rock, which is crushed into arched folds and lies unconform-ably on the crystalline base of the African-Arabian platform. Copper ores are associated with rocks of a certain lithologic composition (argillites, dolomites, feldspathic quartzites) and form series of uniform, sheetlike bodies. The chief ore minerals (pyrite, chalcopyrite, bornite, chalcocite, digenite, and linneite) impregnate the entire mass of the rock and are concentrated along the bedding planes. Most ore bodies are oxidized and leached to a depth of 50-60 m from the surface. Malachite, chalcocite, cuprite, and chrysocolla are found in the oxidized zone.

The question of the origin of copper deposits has not been settled. However, geological data support the syngenetic theory, according to which copper and other valuable components accumulated in the ancient sea basin together with the country rock and then were altered by processes of metamorphism.