acid mine drainage. (3) the exposure, usually as a result of mining, of sulfide bearing minerals to air and water, forming sulfuric acid. This acid dissolves metals such as lead, zinc, copper, arsenic, selenium, mercury, and cadmium into ground and surface water. Acid rock/mine drainage can poison ground and drinking water and destroy aquatic life and habitat. Commonly mined ore bodies that pose the risk of acid rock drainage include gold, silver, copper, iron, zinc and lead. (4) low pH drainage derived from materials with an insufficient capacity to neutralize the acidic products of sulfide and elemental sulfur oxidation and the dissolution products of acidic minerals and amorphous materials. ARD is produced when the neutralization potential is no longer capable of maintaining neutral pH conditions. In the context of mining, may be referred to as acid mine drainage (AMD).
acid mine drainage. Acidic, heavy-metals-laden stream contamination resulting from the drainage of water that contains acidic soils and tailings (residues) from the mining process. Usually associated with surface and underground coal mining.