Acid Mine Drainage :: science

acidulated Mine DrainageFor hund flusheds, even thousands of years, human beings have tapd for metals and stones, and with the advent of greater technology as well as greater needs, the demands for these resources stretch out to grow. While these resources benefit our lives in m each ways, the effects of excavation basin be detrimental, and one such effect is the topic of this essay, acid tap drainage (A.M.D.). The causes of A.M.D. will be discussed, along with some of the physical and biologic problems associated with it. Some prevention and remediation treatments will also be considered. social disease mine drainage refers to peeing (leachate, drainage or seepage) that has come into clear up 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 general sulphide is iron pyrite, or iron disulfide (FeS2), and throughout this essay it will be pyrite that will be the primary sulphide conside red. Acid mine drainage is not a new phenomenon, early mining techniques utilize 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, particularly with soft coal, coal that has high sulphur content. The pyrite that is present in coal seams will be accessible after surface mining when the overlying surfaces be removed or in deep mines that abide 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). When the water comes into contact with the pyrite, the chemical reactions that pass on place causes the water to increase in pH which will fragment heavy metals which stay in solution. However, when the pH levels reach a true stage, the iron can then precipitate out, coating sediments with the characteristic yellow, red or orange colourings (D.E.P. 2, 2002 U.S.G.S. U.S.E.P.A., 2002). The rate that A.M.D. advances is also influenced by the presence of accepted bacteria (Doyle U.S.G.S). A.M.D that has dissolved heavy metals such as copper, lead and mercury can contaminate ground and surface water. Especially at jeopardize are mines that are located above the water table (Keller, 2000 D.E.P. 2, 2002). The sources of water that get polluted can be surface water that permeates into the mine, change ground water flowing through the mine or any water that comes into contact with the waste tailings produced by mines.