Which of the following negative impacts of mining involves rainwater seeping through piles of overburden, creating sulfuric acid?
acid mine drainage
land subsidence air and water pollution
scarring of surface land

The answer is acid mine drainage. Acid Mine Drainage is the outflow of water with acid coming from a mining site. This acid mostly comes from oxidation of iron sulfide that could be found in conjunction with metals. Mining sites usually do sub-surface mining which progresses below water table. And to avoid flooding within the mining site, they have to pump the water outside the mine.