Coal deposits, acid mine drainage

Mine tailings Rocks, minerals, sediments, soils, and other wastes that result from the mining of ore deposits or coal. Mine tailings often contain pyrite and other sulfide minerals, which oxidize in the presence of oxygen and water to form acid mine drainage. 

Another environmental problem associated with sulfur is called acid mine drainage. Groundwater in both coal and metal sulfide mines can become contaminated with sulfuric acid. This is particularly a problem in the coal mines of the Appalachian Mountains. Coal deposits often contain pyrites. Metal ores can include toxic salts of zinc, lead, arsenic, copper, and aluminum. In both cases, acid mine drainage can kill fish and other aquatic organisms, as well as corrode boats and piers. Streams sometimes turn red in color because of the iron content from the mine... 

Acid mine drainage (AMD) is one of the largest environmental problems faced by mining and mineral industries globally (Akcil and Koldas 2006 Akabzaa et al. 2007). AMD is mainly associated with sulphide-rich metalliferous ore deposits, viz., copper, lead, zinc, gold, nickel, tin, and uranium mines (Naicker et al. 2003 Nieto et al. 2007) and coal mines (Bell et al. 2001 Sahoo et al. 2012), which were formed under marine conditions and contain abundant reactive framboidal pyrite (Carrucio and Fern 1974 Campbell etal. 2001). In Table 1, we present a list of well-known AMD sites worldwide. 

Common rock-forming mineral, although most Al-bearing silicates quite insoluble. Potentially soluble Al-hydroxides, hydroxysulfates form in lateric ore deposits, tropical soils, and precipitate in streams affected by acid-rock drainage. Al-rich soluble salts can occur in evaporative lake sediments, and in mine wastes. Potentially reactive forms in cement, concrete, smelter emissions, coal fly ash. 

Mining also adds to the heavy metal pollution problem. As the earth is mined, deposits of minerals, which contain metals, are exposed. If the chemicals used in extracting ore or coal deposits are acidic, then the metals in the minerals are dissolved, and they may make their way into the surface water and sometimes the groundwater. This problem is sometimes controlled with a process that isolates mine drainage and then treats it to remove the metal ions. 

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