Acid mine drainage (AMD) and It''s control

Acid mine drainage (AMD) isamong the most significant environmental challenges facing the mining industry worldwide.It occurs as a result of natural oxidation of sulphide minerals contained in mining wastes at operating and decommissioned mine sites.AMD may adversely impact the surface water and groundwater quality and land use due to its typical low pH,high acidity and elevated concentrations of metals and sulphate content.Once it develops at a mine,its control can be difficult and expensive. The most effective method of control is to minimize penetration of air and water through the waste pile using a cover, either wet (water) or dry (soil), which is placed over the waste pile. Despite their high cost, these covers cannot always completely stop the oxidation process and generation of AMD. Application of more than one option might be required. Early diagnosis of the problem, identification of appropriate prevention/control measures and implementation of these methods to the site would reduce the potential risk of AMD generation.AMD prevention/control measures broadly include use of covers, control of the source, migration of AMD, and treatment.