Copper is used extensively as an alloying ingredient and in pure form because of its excellent conductivity and resistance to corrosion. It is a main component of brass and bronze. With the advent of electricity, as well as the telegraph and telephone, large-scale copper mining became economically viable for the first time. In the United States, the main sources are located in Montana, Arizona, Utah and Michigan. South American deposits were developed and controlled by U.S. companies until the 1960s when nationalization swept the continent.
Copper is found on every continent in the form of sulfide, oxide and carbonate compounds.
In the Western Hemisphere, major mining operations are located in the United States, Chile, Peru, Mexico and Canada. World mine production totaled 12.3 million tonnes in 1998, up from 1997's 11.5 million tonnes, according to the World Bureau of Metal Statistics. Chile was the world's largest producer at 3.7 million tonnes, up from 3.4 million tonnes. The United States was second at 1.86 million tonnes, down from 1997's 1.94 million tonnes. The year was marked by the extended influence of the Asian economic crisis.