Acid Mine Drainage Prevention through the Dry Coating Method Using Fly Ash and Bottom Ash

Abstract

Acid mine drainage poses a significant challenge in open-pit coal mining, particularly in Indonesia, necessitating the development of effective prevention and control methods. This research aimed to assess the impact of fly ash (FA) and bottom ash (BA) coating on the mixing ratio of potentially acid-forming (PAF) and non-acid-forming (NAF) materials using a leaching column over an 8-week period. The results revealed a trend of increasing pH values and decreasing sulfate and metal concentrations in the leachate. Mixing 25% FABA in both PAF scenarios produced leachate with total concentrations of S, Fe, and Mn at 0.026 mg/L, 0.117 mg/L, and 0.677 mg/L, respectively, with a pH close to neutral (6.28). Kinetic tests indicate TDS and EC values in the resulting leachate at 1221 ppm and 2442 µs/m. This study demonstrated that PAF coating using NAF and the fly ash bottom ash (FABA) is an effective method for preventing or minimizing the generation of acid mine drainage.