How an 1863 discovery put Arizona on the copper map – by Mark Nothaft (Arizona Republic – July 5, 2017)

It’s hard to imagine the scale of the Morenci Mine in the southeast portion of the state, but you can get really close to it. Literally.

Take a drive along U.S. Highway 191, and one of the world’s largest open-pit copper mines and leaching operations resembles the Grand Canyon in its multi-hued red rock expanses, layered and intricate and spell-binding. The road, which roughly follows the same path as the Coronado Expedition of 1540 from Mexico to the fabled Seven Cities of Cibola, winds through the middle of it.

You think you see Fray Marcos de Niza on horseback in the distance, and then, another detonation from the miners below shakes you back to reality. Boom! Monster bulldozers and dump trucks, four or five times the size of the ones we see in the city, scoop up loosened earth and haul it off for processing.

Serious science and business

There’s some serious science and business happening at the site about 50 miles north of Safford, operated by mining concern Freeport McMoran of Phoenix. In addition to copper concentrate, the site produces molybdenum, which is used in high-strength alloys.

“In terms of annual production, Morenci was the fifth largest copper producer in the world, producing 550,000 tons of copper during 2016,” retired geologist David Briggs of Tucson says. “Morenci accounted for approximately 33.9 percent of U.S. copper production during 2015.”

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