Investigation of the natural beneficiation of coal mine drainage. [96 references]

This study was undertaken to determine the influence of certain phenomena on the natural beneficiation of coal mine effluents after first verifying that natural beneficiation had occurred. The complex interrelationship of effluent, air, and receiving water temperature was found to be a major factor in this beneficiation. The method for establishing whether beneficiation had occurred was the comparison between theoretical and actual changes in the mineral composition of the stream and pond which were monitored. The theoretical values were based on the combined effect of neutralization and dilution; while the actual values were based on material balances around the various sampling points. Although varying degrees of beneficiation were obtained depending on the parameters and environmental conditions, positive improvement in the quality of the water was found in all cases. This beneficiation ranged from ten to ninety percent reduction in the constituents present as compared to the initial total loading of the water. Such factors as temperatures, flow rates, aeration, sediments, densities, chemical composition, and depth of channels all contributed a complex influence on beneficiation. However low temperatures had the greatest positive influence on this beneficiation. In fact the most startling conclusion of this project was that the lower the airmore » and/or receiving water temperatures, the greater the degree of beneficiation. The percent reduction in mineral constituents remaining in the water was greater at low temperatures than it was at high or moderate temperatures.« less