Rust-colored piles of mine waste and sun-bleached wooden derricks loom above the historic Colorado mountain town of Leadville—a legacy of gold and silver mines polluting the Arkansas River basin more than a century after the city’s boom days. The Environmental Protection Agency has been cleaning the area up for decades. One fledgling company called CJK Milling says it can help—it would “remine” some of the waste piles to extract more gold and silver from ore discarded decades ago when it was less valuable. The waste would be trucked to a nearby mill, crushed to powder, and bathed in cyanide to extract trace amounts of precious metals. The proposal comes amid surging global interest in re-processing waste containing discarded minerals that have grown more valuable over time and can now be more readily removed. These include precious metals and minerals used for renewable energy that many countries including the U.S. are scrambling to secure. Backers say the Leadville proposal would speed up cleanup work that’s languished for decades under federal oversight with no foreseeable end. They speak of a “circular economy” for mining where leftovers get repurposed. “The idea of reprocessing old waste is as old as mining is itself,” said Nick Michael, a representative of CJK Milling. “Today we’re coming back to these, and we’re saying they have value. And more importantly, they need to be cleaned up.” Yet for some residents, reviving the city’s depressed mining industry and stirring up waste piles brings them back to a polluted past they don’t want to revisit. “We’re sitting in a river that 20 years ago fish couldn’t survive,” Brice Karsh, who owns a fishing ranch downstream of the proposed mill, said as he threw fish pellets into a pool teeming with rainbow trout. “Why risk that?” The company’s process doesn’t get rid of the mine waste. For every ton of ore milled, a ton of waste would remain—minus a few ounces of gold. At 400 tons a day, waste will stack up quickly. In September, gold prices reached record highs, and demand has grown sharply for critical minerals such as lithium used in batteries. This article was provided by The Associated Press.