Characterization Study of Coal-Combustion Ash For Acid Mine Drainage Prevention

Abstract

Prevention of the acid mine drainage generation is the best effort to reduce one of the environmental issues in mining activities. This effort can be done by covering sulphide-bearing rocks by suitable and available rocks or materials to prevent the oxidation reaction of sulphide minerals with water and air. One of the materials that might be utilized is coal-combustion ash from the power plants, in the form of fly ash and bottom ash. It is necessary to conduct material characteristization of the ash so that the plan to form a cover layer can be carried out optimally. The test is carried out for mineralogical analysis using XRD and XRF; static geochemical tests with Paste pH, Net Acid Generation (NAG), Acid Neutralizing Capacity (ANC), Maximum Potential Acidity (MPA); and kinetic test with the free drainage column test. The test results show that FA and BA have non acid forming (NAF) characteristics so that they have the potential to be used as cover layer for potentially acid forming (PAF) material. In addition to geochemistry, geophysically FA has the ability to reduce water infiltration because it contains a lot of clay minerals, while BA has the ability to maintain moisture in the cover layer due to sandy properties of the material.