RARE EARTH ELEMENT AND CRITICAL MINERAL ENRICHMENT IN COAL AND COAL-ADJACENT STRATA OF THE UINTA REGION

This study aims to quantify rare earth element (REE) enrichment within coal and coal-adjacent strata in Utah’s Uinta Region and Western Colorado. REEs are a subset of critical minerals (CM) utilized for renewable energy technology in the transition toward carbon-neutral energy. While REE enrichment has been observed within Appalachian coals, there has been limited evaluation of Western U.S. coals. In this study, samples from seven active mines and seven stratigraphically complete cores within the Uinta Region are geochemically evaluated via portable X-Ray Fluorescence (pXRF) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) elemental abundance methods. Results from 3,362 pXRF and 145 ICP-MS analyses suggest that stratigraphically coal-adjacent carbonaceous shale and siltstone units show REE enrichment (REE>200ppm), as do igneous dikes that cross-cut coal seams. Most coal seams themselves do not display REE-enrichment, except in rare cases. Historical evaluations of geochemical data on Uinta Region coal and coal-adjacent data are sparse, emphasizing the statistical significance of this study’s analyses. These results support the utilization of active mines and coal processing waste piles for the future of domestic REE extraction, offering economic and environmental solutions to pressing global demands.