Characterization and comparison of mine wastes in Can Coal Basin, northwest Turkey: a case study

The Can Coal Basin is a major coal-producing site in northwest Turkey that has faced acid mine drainage problems since the 1980s. This study characterized and compared mine wastes from the Etili and Comakli open-pit coal mines in the Can Coal Basin physically, mineralogically, and geochemically for acid mine drainage potential and metal(loid) mobility. Mineralogical analysis determined pyrite to be the major sulfide mineral in the Etili and Comakli coal and mine wastes, while dolomite and calcite were abundant in the mine wastes from the Comakli site. Concentrations of Al, As, Mn, and Pb in these mine wastes are higher than in Turkish and world coals. The enrichment factor showed moderate enrichment of Pb and significant enrichment of As in the Etili and Comakli mine wastes, respectively. Static tests indicated acid generation potential in all Etili and some Comakli mine wastes. The modified synthetic precipitation leaching procedure revealed that greater concentrations of Al, Fe, Mn, Ni, Pb, and SO42− were released from pyrite-rich mine wastes. Physical, mineralogical, and geochemical factors affecting acid mine drainage were highly variable within and between sites. Increasing concern over significant environmental health effects of low-pH, metal(loid)-polluted mine wastes necessitates remediation of the mine sites.