Acid mine drainage: an assessment of kinetic tests for predicting acid generation from the waste rock of the Osamu Utsumi Mine

Acid mine drainage results from the oxidation of sulfide-bearing rocks when they are exposed to atmospheric conditions, leading to the generation of sulfuric acid and acidic waters. This environmental issue escalates when surrounding rocks lack the ability to neutralize the acidity, resulting in low pH conditions that exacerbate the leaching of metals and metalloids into the environment, adversely affecting water quality. One notable example of this situation is the Osamu Utsumi Mine in Caldas, MG. This study aimed to assess and compare two kinetic tests to predict the acid generation from the mine's waste rock. The tests employed were a Soxhlet extractor method and a leaching column. The leachates obtained from both methods were analyzed for various physical-chemical parameters including pH, Eh, electric conductivity, as well as for the presence of metals and metalloids. The findings contributed valuable insights into acid formation processes and their implications for environmental management in abandoned mining sites.