Acid mine drainage refers to water (leachate, drainage or seepage) that has come into contact with oxidised rocks or overburden that contains sulphide material (coal, zinc, copper, lead). (Keller, 2000; U.S.G.S.; U.S.E.P.A., 2002). A common sulphide is pyrite, or iron disulfide (FeS2), and throughout this essay it will be pyrite that will be the primary sulphide considered. Acid mine drainage is not a new phenomenon, early mining techniques utilized gravity to avoid water pooling, resulting in the water becoming polluted by acid, iron, sulphur and aluminium (U.S.E.P.A., 2002). It is most commonly associated with coal mining, especially with soft coal, coal that has high sulphu

US Geological survey (U.S.G.S.). Mine drainage. Retrieved from internet source on May 16 2002: http://geology.er.usgs.gov/eastern/environment/drainage.html

In summary, acid mine drainage is the result of chemical reactions between oxygen, water and sulphide bearing materials that are the result of mining processes. The water is acidic and can contaminate ground and surface water, polluting streams. The results of this pollution can cause changes in the nutrient cycles affecting both plants and animals, and it can disrupt an ecosystem and alter the species diversity. The acidic water can also affect physical structures and have an effect on local tourism. Abandoned mines, such as the Tar Creek area, are of high risk in causing A.M.D., especially if the mines have altered the natural water table, or are located close to the water table. A.M.D. can be avoided through techniques such as submerging wastes to exclude oxygen contact, sealing wastes above the water table, as well as water management techniques. Also possible is the use of artificial aerobic or anaerobic wetlands to treat the affected water. Through mitigation techniques, it should be possible to reduce if not eliminate acid mine drainage as an environmental and social problem.

What_is_Acid_Mine_Drainage.htm (1) (Last updated on 12 October 1997)

r content. The pyrite that is present in coal seams will be accessible after surface mining when the overlying surfaces are removed or in deep mines that allow oxygen access to the previously inaccessible pyrite-containing coal (D.E.P. 1, 1997). After pyrite is exposed to air and water, sulphuric acid and iron hydroxide are formed, creating an acidic runoff (D.E.P. 1, 1997; 2 2002).

http://www.epa.gov/region03/acidification (Last updated on Saturday, May 11th, 2002)

Office of Surface Mining (O.S.M). Acid mine drainage prevention and mitigation. Retrieved from internet source on June 4 2002: http://www.osmre.gov/amdpvm.htm (last updated on 3 May, 2002)

Other prevention techniques that are also remediation techniques are the construction of artificial wetlands (D.E.P. 2, 2002). Aerobic wetlands are only able to effectiv

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