Geochemical Characterization of Rocks to Analyze the Source of Acid Mine Drainage Generation

Abstract PT. Batubara Lahat, located in South Sumatra province, is a company that conducts coal mining using the open pit method. The open pit mining method creates a flow of water that has low pH properties commonly known as acid mine drainage and then becomes one in the lowest area of mining which is commonly called a sump. Acid mine drainage is water produced through oxidation of sulfide minerals in rocks by oxygen in the air in an aqueous environment. In good mining engineering regulations, companies must be responsible for overcoming the potential for the formation of acid mine drainage, one of which is by analyzing the quality of water that will be formed in testing as a first step by understanding the geochemical characterization of rocks on a laboratory scale. Geochemical characterization of rocks is determined by several laboratory tests, namely, static tests and kinetic tests, where in static tests are usually carried out by measuring total sulfur, paste pH, NAG pH, and Acid Base Accounting (ABA) methods, while in kinetic tests are usually carried out by the Free Draining Column Leach Test (FDCLT) method. The samples used in this study were the side rock samples of PT Lahat Coal, namely BL-A1, BL-A2, BL-B, BL-C, BL-D, BL-E and BL-F. Based on the results of this study, samples BL-A1, BL-A2 are categorized as potentially acidic rocks or PAF while samples BL-B, BL-C, BL-D, BL-E and BL-F are categorized as rocks that are not potentially acidic or NAF. The results of characterizing the geochemistry of these rocks can be a consideration for PT. Batubara Lahat in managing rock dumps in order to meet the environmental standards that have been set.