Under an approved remining program, a mine operator can remine abandoned coal mines without assuming treatment liability of the existing degraded water, as long as the discharging waters are not raised above the revised effluent standards. A salient yardstick of the success of remining is reduction of the acidity and iron pollution load from pre-reroining (baseline) conditions. The baseline sampling scheme, crucial to mine discharge characterization, is used to determine remining induced pollution load changes. To determine the optimum baseline sampling scenario in terms of water quality characterization, the pre-activation data from 115 discharges from 39 Western Pennsylvania remining permits were analyzed using the treatment initiation mechanism employed by the Pennsylvania Department of Environmental Resources. The best sampling duration was the maximum duration analyzed, 12 months. A year's worth of data will include data from both high and low flow conditions. The optimum sampling frequency was determined to be one sample per month. Sampling on a time-consistent basis eliminates the potential bias of oversampling high or low flow conditions. Sampling twice per month may improve the characterization, if performed on a consistent time interval. However, the improvement appears to be slight and the increased sampling may not be cost-effective.