Startup Recovers Copper From Abandoned Arizona Mines

In central Arizona, approximately 90 miles east of Phoenix, a former open-pit copper mine, closed in the 1980s, now holds a significant volume of water. These "pit lakes," formed by accumulated rainwater and groundwater, are maintained to prevent environmental contamination but otherwise remain largely unused. However, this water is rich in critical minerals, including copper, a metal facing a looming shortage. SiTration, a startup originating from the Massachusetts Institute of Technology (MIT), has initiated a two-month pilot program aimed at recovering copper from this legacy mine water. According to SiTration CEO Brendan Smith, the pilot is designed to extract two tonnes of copper from the pit lake. While this quantity is modest compared to the output of traditional copper mines, Smith stated that the pilot's primary objective is to validate the startup's technology. He expressed optimism that this approach could "unlock a whole new source of copper that’s sitting there on the table for taking." The pilot is taking place at the BHP Copper Cities site in Arizona, which features a legacy pit lake.

The demand for critical minerals, including copper, is experiencing a substantial surge. These materials are indispensable for a wide array of modern technologies, such as batteries, electric vehicles, drones, computer chips, and data centers. Copper, in particular, is in high demand due to its essential role in these sectors. Smith highlighted that a single hyperscale data center might require as much as 50,000 tons of copper, which is equivalent to the annual production of an entire copper mine. Furthermore, the existing electric grid relies heavily on copper for components like transistors and transmission lines. Projections indicate that by 2040, the overall demand for copper could increase by 50%. Concurrently, the supply of newly mined copper is diminishing. Experts forecast a global copper deficit of 10 million metric tons by the same year. A significant contributing factor to this supply challenge is the declining ore grade; the concentration of copper in mined ore has decreased by nearly 50% since 1990, meaning current mining operations yield half the amount of copper from the same volume of ore compared to three decades ago. This represents a substantial decline in resource efficiency for traditional mining.

SiTration's technology focuses on extracting dissolved minerals from water, a process that differs significantly from conventional mining. Traditional methods involve physically excavating large quantities of rock and then processing it to separate the desired minerals. This often results in significant waste rock and tailings. In contrast, SiTration's approach targets the minerals already leached into the water bodies, potentially offering a more environmentally benign and resource-efficient method for copper recovery. The company's innovation lies in its ability to selectively extract specific minerals from complex aqueous solutions. This selective extraction is crucial for efficiently obtaining copper without also recovering unwanted elements, thereby reducing processing complexity and costs. The success of this pilot program could pave the way for the redevelopment of numerous abandoned mine sites globally, transforming them from environmental liabilities into valuable resource assets. The company's origin at MIT, a leading research institution, suggests a strong foundation in scientific and engineering principles underpinning their recovery technology. The pilot's two-month duration is intended to provide sufficient data to assess the technology's scalability and economic viability for larger-scale operations, potentially addressing a critical gap in the global copper supply chain.