RARE EARTH AND STRATEGIC ELEMENTS IN ILLINOIS COAL DEPOSITS AND COALMINE WASTE
Here we report preliminary data on the concentrations of REY in samples of coal, cleaned coal and coal refuse from a coal preparation facility at an underground mine in Saline County, IL, as well as acid mine drainage at an abandoned coal mine site, in Jackson County, IL. Geochemical analyses indicate that some coals in the Illinois Basin affected by hydrothermal activity can be enriched in Ce, La, Nd, and Y, with the total REY concentration > 150 ppm, as well as non-REY elements such as Ge, Ga, V, Cr and Ni. The ultrabasic igneous dikes that intrude into the underground coal seams also have elevated concentrations of Ce, La, Nd, Pr, and Y, with the total REY concentration > 400 ppm. The coal refuse samples from the coal preparation facility are enriched in REY by a factor of ten compared to the cleaned coal prepared for commercialization. Our recent survey at the abandoned coal mine site indicates that the acid mine drainage has elevated concentrations of Y, Nd, Ce, and Gd with the total REY concentration > 1 mg/L.
These REY preliminary data suggest that further research should focus on identifying the hydrothermally-altered coals in Illinois Basin as well as surveying the roof and floor rock and the within-seam partings in the mined product. Additionally, further investigations may include geochemical characterization of coalmine acid mine drainages across the Illinois Basin.