Copperbelt of Chile

a narrow zone of porphyry copper deposits, stretching along the Cordillera de los Andes between 36° and 18°S lat. and extending further north into Peru. The total length of the belt is 2,100 km. Commercial development of the copper ores began here in the second half of the 19th century. In 1972 total reserves of Chilean deposits were estimated at approximately 59 million tons of copper, with an average copper content of 1.3 percent. Production amounted to 716,800 tons per year. Over 85 percent of the metal was extracted from the ores of three deposits: Chuquicamata, El Teniente, and El Salvador. In 1972, copper reserves in Peru totaled 23 million tons, with an average copper content of 1 percent. Annual production amounted to 217,000 tons.

The formation of the Copperbelt of Chile is associated with the development of the Cenozoic geosyncline of the Andes and with tectonic movements of the Paleogene and Neocene, which were accompanied by intensive volcanism and the introduction of surficial intrusions of acid and medium composition. Porphyry copper deposits associated with stocks of granodiorites and quartz diorites are of central importance. They consist of large blocks of rock containing veins and inclusions of chalcopyrite, pyrite, bornite, enargite, and molybdenite. Leached zones and zones of secondary sulfide enrichment with richer chalcocite, covellite, and cuprite ores are usually found in commercial deposits.