Identification and Characterization of Coal and Coal By-Products Containing High Rare Earth Element Concentrations

The focus of this study it to identify and characterize coal and coal related materials in the Illinois coal basin that contain high rare earth element (REE) concentrations, particularly those resources in the Springfield, Herrin and Baker coal beds. Previous studies showed areas of elevated concentration in this region, however, the amount of data available is limited in comparison with other coal basins. Sampling from the mid-1980’s showed some sampling sites containing >300 ppm REE on a whole basis, however most sampling sites showed lower concentrations. Examination of DOE/NETL’s Energy Data eXchange (EDX) public database shows that REE content in coal and coal related material generally increases with ash content. Investigations at the University of Kentucky (UK) showed that some layers within coal seams contained significantly higher REE concentration than others, most notably higher ash content layers associated with partings or roof and floor material. For this reason, cores will be evaluated in layers rather than simply as a homogeneous composite. Specifically, cores will be evaluated in layers based largely on inorganic content to identify REE enriched zones within seams that will be suitable for potential REE recovery. Larger samples will be taken from active mines and preparation plants where cores identified likely REE concentration >300ppm and subjected to additional separations based on physical properties to further elucidate REE partitioning and/or concentration during coal formation. These efforts will be conducted in coordination with project partner mining companies currently mining several seams throughout the Illinois Basin. By working closely with the coal companies, our samples will be representative of both current (mine face and preparation plant) and future mining in the Illinois Basin.