SURFACE MINING OF COAL AND WATER CHEMISTRY – CASE STUDY IN WEST VIRGINIA, USA
Many geochemical parameters in surface and ground water from surface mining areas were elevated and statistically different (p<0.05) compared to control areas (84 samples taken during 2011-2012 in all seasons). In the Coal River Valley all surface and ground water samples had pH values of 8-9 and conductivities exceeding 1000 microSiemens, compared to pH values of 6-7 and conductivities of <200 microSiemens in all control area samples (no surface mining). Ammonium concentrations were significantly higher in surface mining areas (30-1500 µg/L) compared to controls (0-40 µg/L), possibly linked to ammonium nitrate used as an explosive in mountaintop removal mining. Extractable hydrocarbons such as polycyclic aromatic hydrocarbons (PAHs) and phenols (possibly coal-derived) were found in many surface and ground water samples from surface mining areas, including some that were used as drinking water supplies, but were not observed in samples from control areas. Extractable hydrocarbons were in the range of 0.1-100 µg/L for individual compounds. These observations suggest possible links between surface mining and water quality. Ongoing studies are examining specific sources of these contaminants from surface mining or other sources.