Pinal County: Copper Corridor

The Pinal County portion of Arizona’s Copper Corridor runs from Superior in the north to Oracle Junction in the south, encompassing some of the most interesting geography in the state – along with a fascinating slice of the state’s history and scenery. Developed by the Copper Corridor Economic Development Coalition and named for the enormous wealth that has been producead by the mining activity throughout the region, it provides a look at the past, the present, and the future of the Copper State. The mining history and physical linkage to the rest of the state makes it a truly special part of Pinal County. Arizona is the number one producer of copper in the country and, as many different precious metals tend to be found in the same strata, the results here have been astounding. The corridor includes a history of successful mines all the way from Superior in the north to Oracle in the south, with more to come. Here’s a brief look at some of those mining successes.

Superior, the northern gateway to the corridor, is about 60 miles east of Sky Harbor Airport, on Highway 60. Their history began in 1875 with the Silver King Mine, Arizona’s richest ever silver mine. The Silver Queen Mine followed in 1881. Among those attracted to the new boomtown were Wyatt Earp, his common-law wife Mattie, and Doc Holiday. When Wyatt and Mattie broke up after the 1882 gunfight at the O.K. Corral in Tombstone, she returned and is buried in the Pinal Cemetery. The Silver Queen became a major copper mine when the silver played out and, as a result, Picket Post Creek became known as Queen Creek, flowing down hill to lend its name to Queen Valley and the town of Queen Creek. The town was named Superior in 1902 after the mine’s owners. Magma Copper took over the mine in 1910 and it became a huge producer. When it ceased production in 1996, the mining operation had processed over 27 million tons of ore, producing approximately 1.3 million tons of copper, over 36,000 tons of zinc, 686,000 ounces of gold, and over 34 million ounces of silver. Further exploration has now found what is purported to be the largest copper deposit in North America, some 7,000 feet below the surface. It’s estimated to include over 1.6 billion tons of ore, and is projected to be a $64 billion project over the next 60 years, providing over 25% of the country’s copper needs for decades. Using modern techniques and a projected $6 billion investment by Resolution Copper (the largest investment in Arizona history), work is under way by to recover it.

The Ray mine, a little over 10 miles to the south, has been in production for 140 years. Primarily known as a copper mine, the deposit also includes gold, silver, molybdenum, zinc, and lead. The open pit mine continues to process some 250,000 tons of ore per day, with proven and probable reserves of over 800 million tons. It is projected to produce until at least 2044 and has been directly responsible for the development of the towns of Kearny and Hayden.

From Winkelman, at the confluence of the San Pedro and Gila Rivers, to Oracle, mining is joined by cattle ranching and offers a stunning selection of riparian and wilderness area access points along the San Pedro River Valley for outdoor exploration and activities.

Mammoth is another town with a very successful mining history – with a potential for even more in the future. It became a major source of molybdenum during World War I, adding to its gold mining heritage. The nearby ghost town of Copper Creek is known to contain a major copper deposit, including over 500 mineralized breccia pipes of concentrated ore, raising new interest in developing the claims.

In the 1980s, the San Manuel mine was rated the largest underground copper mine in the world in terms of production capacity, size of ore body, and infrastructure, later adding an open pit operation, producing almost 800 tons of ore. They had the largest smelter of its type in the world and developed geologic modeling techniques that are still in use by geologists worldwide to locate and estimate the size of ore bodies.