Coal waste may help US secure rare earth supply for clean energy and defense

Researchers at the South Dakota School of Mines and Technology have developed a novel method to extract rare earth elements (REEs) from coal mine waste, including overburden rock and coal ash, which are typically discarded or stored long-term. Led by Professors Venkataramana Gadhamshetty and Purushotham Tukkaraja, the team focused on coal mines in Wyoming and identified valuable REEs such as yttrium, dysprosium, erbium, ytterbium, and gadolinium—critical components for clean energy technologies, electronics, and national defense. Their three-stage extraction process integrates physical crushing, environmentally friendly chemical leaching, and a biological step where microorganisms absorb and concentrate the dissolved REEs, enhancing recovery efficiency and sustainability. Beyond solid waste, the researchers are also applying this approach to coal mine wastewater, aiming to recover REEs from contaminated water streams. Supported initially by the National Science Foundation and later by the U.S. Department of the Interior and the Office of