Leaching of Metals and Trace Elements from Sulfide-Bearing Coal Waste in Southwestern Illinois

摘要

Metal sulfides, chiefly pyrite and minor sphalerite, associated with the Herrin (No. 6) coal member of the Pennsylvanian Carbondale Formation, have been concentrated in a coal refuse deposit in southern Illinois. Chemical, petrographic, and x-ray-diffraction data for 34 cores, show that the upper two meters of material have been leached of sulfides in the thirty years since washing operations ceased. Oxidation of pyrite has produced highly acid waters with high concentrations of iron, zinc (up to 200 parts per million) and toxic trace elements that have leached downward to a water system perched on the underlying Illinoisan glacial drift. Deep well samples in the refuse pile are more saturated with metals than are the runoff waters and shallow-well samples. Metal recovery does not appear to be economically feasible at this site. (ERA citation 08:031091)