Asarco Mission Mine, Arizona

One of the largest mining operations in the United States, the Mission Complex is a copper and silver mining network, featuring an open-pit mine comprised of the Mission, Eisenhower, Pima, Mineral Hill and South San Xavier properties, as well as the neighboring North San Xavier mine. The mine is operated by Asarco (which was purchased by Mexico's largest mining company Grupo Mexico in 1999), producing around 475,000 tons of concentrated copper a year, with a reserve life estimated at 2033. The main pit is 2.5 by 1.5 miles, and 1,200 feet deep. Usually ranked the third largest copper mine in Arizona, the state that produces 65% of the nation's raw copper. It is located south of Tucson, adjacent to the Twin Buttes mine, and the Sierrita Mine.