BOULDER COUNTY — Poofs of smoke and coal ash wafted from a 30-foot pit on Marshall ... from an underground seam and dumped them onto a pile of dirt and rock, where a bulldozer mixed it all ...

Published in September, the survey revealed that 11 million tons of REEs could be extracted from domestic coal ash stashes – a big jump from the current estimated U.S. reserves of 1.4 million tons.