In recent years, the limestone treatment of AMD in the Blackwater River has met with success with the effort receiving an award from the U.S. Office of Surface Mining. AMD is created when sulfite-bearing mineral strata are exposed to air and rainwater, such as when surface mining occurs. The sulfuric acid produced from the sulfite reaction can dissolve metals such as iron, aluminum, and magnesium. By 2004, the combination of acid and dissolved metals drainage had destroyed or damaged about 12,000 miles (19,300 km) of streams in Appalachia, including the Blackwater River and streams in its watershed.