Effectiveness of Pennsylvania's remining program in abating abandoned mine drainage: water quality impacts

The Pennsylvania Department ofEnvironmental Protection (PaDEP) has been issuing surface mining permits since 1984 that authorize remining in areas that will affect preexisting pollutional discharges. These permits require the mine operator to employ best management practices to reduce pollution loading from abandoned mine discharges. A total of 110 completed mining operations with 233 discharges were evaluated to determine the impact to water quality. Overall, acid loading from these discharges was reduced by 7,200 kg (15,900 lbs) per day or 61%. Metal loadings were also reduced. For acidity, 49 % of discharges improved or were eliminated, 52 % showed no significant change and fewer than 1 % got worse. Loading reductions resulted from a combination of reduced concentrations and lower flows