Arizona’s Morenci copper mine, owned by Freeport-McMoRan Inc., is pioneering sulfide leaching technology to recover low-grade copper from waste rock piles. After 154 years of operation, all easily accessible copper has been extracted, leaving nearly 10 million tons of low-grade copper in towering piles of waste rock. Freeport-McMoRan aims to produce 400,000 tons of copper by 2030 using this innovative method, enough to wire over 4.3 million electric vehicles. The technology is gaining attention as global demand for copper rises due to electrification and renewable energy initiatives.
Sulfide leaching uses chemical reagents to extract copper from chalcopyrite, a sulfide mineral traditionally considered difficult to process. Unlike conventional mining methods that require extensive grinding and smelting, leaching offers a potentially cheaper, faster, and more environmentally friendly alternative. Freeport-McMoRan has already recovered 100,000 tons of copper using this process at Morenci. Other major miners like BHP and Rio Tinto are also investing in similar technologies, with startups such as Jetti Resources and Ceibo developing tailored solutions.
While promising, scaling sulfide leaching technology remains a challenge. Economic viability and technical feasibility at industrial levels are still being tested. Freeport-McMoRan has shifted away from earlier partnerships with startups like Jetti at its El Abra mine in Chile and is now pursuing proprietary methods. BHP is testing multiple leaching technologies at its Escondida mine in Chile, evaluating cost-efficiency against recovery rates.
Morenci’s efforts align with U.S. President Donald Trump’s critical minerals agenda, which emphasizes domestic production to reduce reliance on imports. The mine supports approximately 13,000 direct and indirect jobs and generates $1.5 billion annually for Arizona’s economy. As global competition for copper intensifies, advancements at Morenci could play a pivotal role in securing U.S. supply chains.
