Coal ash—the chalky remnants of coal that has been burned for fuel—has been piling up across the United States for decades. But new research led by The University of Texas at Austin has found that the national coal ash supply contains enough rare earth elements to significantly bolster the national supply without any new mining. Coal ash—the chalky remnants of coal that has been burned for fuel—has been piling up across the United States for decades. But new research led by The University of Texas at Austin has found that the national coal ash supply contains enough rare earth elements to significantly bolster the national supply without any new mining. Earth Sciences Phys.org – latest science and technology news stories