Flooded mine workings underlie approximately 17,500 ha of the northern anthracite field in northeastern Pennsylvania. The U.S. Bureau of Mines is examining the hydrology and geochemistry of this large mine pool complex in order to identify flow patterns, sources of acid mine drainage, and chemical stratification. Fluid resistivity, temperature, ph, and oxidation reduction potential are being measured with down-hole instruments in 12 mine shafts open to depths down to 460 m. Samples collected at various depths are being analyzed for concentrations of total and ferrous iron, sulfate, manganese, aluminum, ph, alkalinity or acidity, and fecal coliform bacteria. Water flowing from the mine pool remains heavily contaminated by acid mine drainage more than 30 yr after the pool started to form. One goal of this study is to determine if pyrite oxidation is still adding to the pollutant load or if previously oxidized products are being flushed from the pool. A preliminary survey of water quality at depth suggests that changes in chemical parameters within the pool are closely related to the mined-out coal seams. Generally, water quality was found to decrease gradually with depth and to change sharply at the elevation of mined-out beds.
Proc. 1st Int. Mine Water Conf., Budapest, Hungary, Apr. 19-23, 1982, PP. 27-42