Acid Mine Drainage Management Plan and Utilization of Fly Ash as Neutralizing Agent (A Case Study of Post-Mining Pits in Palaran, East Kalimantan)

Abstract

With high levels of domestic production, consumption, and coal exports in East Kalimantan, the outcome will be directly proportionate. Disruption of abiotic, biotic, and cultural factors, such as the environmental impact on Kopi Palaran Street, where there are four abandoned post-mining pits surrounded by residential areas and filled with acid mine drainage. A new issue resulting from the effects of post-mining activities is residents using acid mine drainage from post-mining pits without treatment. The acidity level of the acid mine drainage that the people of Kopi Palaran Street used for daily sanitary reasons ranged from pH 2.8 to pH 3.3 and included relatively low-level Fe and Mn metal. According to the results of laboratory tests on the acid mine neutralisation process, adding 25 g of fly ash to 1000 mL of acid mine drainage can raise the pH of the acid mine water to 8.7 due to the process of alkaline minerals of the fly ash, such as CaO, dissolving acidic minerals. It can also increase the Fe metal content to 13.1 mg/L due to the precipitation of ferric hydroxide, while lowering the Mn metal content to 0.38 mg/L.