Predicting Mine Effluent and Ground Water Quality Prior to Mining

摘要

A leaching column technique that produces effluent similar in quality to coal mine drainage in the eastern interior basin has been developed. The columns are charged with 1,000 g of crushed overburden and cycled through the leaching process once a week for 12 weeks. Interrelationships among the important chemical constituents are very similar to those present in actual mine drainage waters, but the overall concentrations of ions are more dilute in the leachates. Multiplying the leachate concentrations by a factor of 4.5 gives values similar to mine waters. Available data suggests that each of the leaching cycles represents about 3 yr of natural weathering, so that the leaching technique can predict the evolution of the mine drainage water over a time span of nearly 40 yr. Use of the leaching technique with drill core samples should provide a method of approximating mine drainage quality in advance of mining and should be useful in identifying potentially toxic units in the overburden. However, the results should be considered to be a worst case situation, because the technique does not consider the effects of reclamation.