Acid Mine Drainage Essay

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Pollution of Waterways from Mine Wastes G. Jeremy Hatton ENV3540 Fall2013 The flow of caustic water out of a mining site is known as acid mine drainage. FeS2 (which is known as pyrite or fool's gold) oxidizes into acid as it weathers from exposure. Pyrite is often found in or around the valuable metals being mined. Metal sulfide mines (where sulfur is found along with metal ore) almost always form acid mine drainage. Most hard rock mines also have problems with acid formation as well. Coal mines also drain large amounts of acidic water. Downstream waters are often poisoned to the point where only microbes can survive by the metals that are dissolved by the acid. This also can be caused by land uses other than mining, such as construction which disturbs the land. Mining causes by far more damage than most other causes of this type of pollution. Acid rock drainage, on the other hand, occurs naturally in some environments without the help of humans. Heavy metals such as arsenic, lead, and copper, along with sulfuric acid contaminate human water sources worldwide. Once rock that can generate acid is crushed and exposed to oxygen and the surface environment, the formation of acid is very difficult to contain or stop. It can continue for a few years or a few thousand years until all the available sulfide minerals are used up. Mines from Roman times have been found which are still producing acid mine drainage. Acid mine drainage is such a serious and persistent issue because of its extreme difficulty to contain, the inability to reverse the chemical reactions once the materials are exposed, and the very long hazard life of the materials themselves. (Paige Cordial, 2012) Desirable metals like copper, gold, lead, silver, zinc, and others are often found in ores high in iron sulfide content. Huge quantities of toxic ores exist locked away

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