The Acid Mine Drainage (AMD) is the number one environmental problem facing the mining industry. AMD occurs when sulphide-bearing minerals in rock are exposed to air and water, changing the sulphide to sulphuric acid. It can devastate aquatic habitats, is difficult to treat with existing technology, and once started, can continue for centuries (Roman mine sites in Great Britain continue to generate acid drainage 2000 years after mining ceased). Acid mine drainage can develop at several points throughout the mining process: in underground workings, open pit mine faces, waste rock dumps, tailings deposits, and ore stockpiles. (Miningwatch).
From collection: Vital Waste Graphics
Philippe Rekacewicz, UNEP/GRID-Arendal