Current performance of a passive wetlands treating acid mine drainage from underground mine seals at Moraine State Park, Butler County, Pennsylvania

Coal mining was conducted in the area of Moraine State Park prior to establishment of the park and associated Lake Arthur. Sixty-nine underground mine entries were sealed during the 1960s and early 1970s along the proposed shore of Lake Arthur. Not all seals were successful and some were leaking acid mine drainage (AMD) and depositing iron hydroxides. A passive wetlands treatment system was constructed in 1996 to treat the AMD from one of these leaking seals. The design life of the system was estimated as twelve years. Six monitoring locations were established, water samples collected, analyzed for AMD parameters, and precipitate thickness measured to determine if the ponds continue to function properly twelve years later. This research determined the wetlands treatment system continues to ameliorate the AMD discharge, determined that the ponds do not need to be cleaned out at this time, recommends a monitoring and maintenance schedule.