Morenci Mine, The Largest Copper Mine In US, Is A Sight To Behold

The Morenci Mine is the largest copper mine in the US and one of the biggest in the world. As of 2007, operations ran around the clock, churning up over 381,000 tons (840 million pounds) of valuable metals every year, according to NASA.

Located in rural Arizona’s Greenlee County, the entire complex takes up around 24,970 hectares (61,700 acres) – about the size of Brooklyn in New York – comprising 20,760 hectares (51,300 acres) of fee lands and 4,208 hectares (10,400 acres) of unpatented mining claims, according to Mining Technology.

The landscape of the mine is characterized by a Martian-like red soil, pitted with deep bowls and giant mounds that have stepped, stratified sides, like the seats of an ancient amphitheater.

Its geological history is millions of years old, but things have been especially eventful in the past century.

Following the global recessions of the late 1970s and 80s, the price of copper slumped and Phelps Dodge, the company that operated the Morenci Mine, decided to lay off thousands of workers. The local economy was deeply dependent on the mine, so the local community was hit hard, with nearly half of Clifton’s population losing their jobs. 

Negotiations between the corporation and the unions fell apart, leading to the Great Arizona Copper Strike between June 1983 and February 1986. Unlike other companies in the wider dispute, Phelps Dodge took a hardline stance, hiring non-union replacement workers and trying to get union members to cross picket lines. 

Events reached fever pitch on August 8, 1983, when the mine was reopened using strikebreaking labour. Thousands of workers blocked the gates in protest, forcing the company to temporarily shut down the mine and agree to a 10-day cooling-off period. The mine eventually reopened again under heavy security from the authorities, with 350 National Guard troops, 425 state troopers, and 160 SWAT sharpshooters deployed to allow the arrival of replacement workers.

The legacy of the strike can still be found in the local area today, but the mining still continues in whole new ways. 

While all of the mine’s easily recoverable copper has been recovered, recent media reports suggest that President Trump’s renewed focus on domestic copper output has reignited interest in the mine. Copper is a key ingredient in many components of electric cars and renewable energy technologies, positioning the metal for a significant surge in demand.

With the help of new technology, companies are looking into new ways of separating copper from chalcopyrite, a copper-iron sulfide mineral which is typically considered difficult to process. So far, they’ve managed to obtain 100,000 tons of copper using “sulfide leaching” techniques, with the aim of producing 400,000 tons by 2030 – that could be enough to build over 36,000 electric vehicles.