Hydro-Geochemical Behavior of Acid Formation of Sulfide Bearing Rocks Based on Kinetic Column Tests

Abstract

Acid mine drainage (AMD) is an important environmental hazard due to its serious chemical contamination to the surface and groundwater resources. To provide enough and representative data for developing restoration techniques, this time-dependent geochemical process should be investigated based on kinetic principles. Thus, the kinetic column test was generally utilized in the earlier studies without any accepted procedures related to the column dimension and properties of materials (such as particle size and mass of samples). To overcome the dissimilarities between the mass release rate of contaminants specified in the laboratory and in the field, and to upscale laboratory-based measurements to the field, kinetic column tests were performed using different columns filled with crushed coarse and fine ore samples. The fluctuations of pH values and the concentration of various constituents were determined during kinetic column tests. The effluents of columns turned to acid after lag time of 21–65 weeks depending on the column dimensions and particle size. Statistically significant predictive models for upscaling geochemical behavior of AMD processes were presented based on simple and multiple regression analyses among column dimensions and main parameters controlling the rate of acid generation.