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Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) refers to the outflow of acidic water from metal mines or coal mines. Acid rock drainage occurs naturally within some environments as part of the rock weathering process but is exacerbated by large-scale earth disturbances characteristic of mining and other large construction activities, usually within rocks containing an abundance of sulfide minerals. Areas where the earth has been disturbed (e.g. construction sites, subdivisions, and transportation corridors) may create acid rock drainage. In many localities, the liquid that drains from coal stocks, coal handling facilities, coal washeries, and coal waste tips can be highly acidic, and in such cases it is treated as acid rock drainage. The same type of chemical reactions and processes may occur through the disturbance of acid sulfate soils formed under coastal or estuarine conditions after the last major sea level rise, and constitutes a similar environmental hazard. ==Nomenclature== Historically, the acidic discharges from active or abandoned mines were called acid mine drainage, or AMD. The term acid rock drainage, or ARD, was introduced in the 1980s and 1990s to indicate that acidic drainage can originate from sources other than mines.〔Dowding, B. & Mills, C,: ''(Natural acid rock drainage and its impact upon background metal concentrations )'', (InfoMine.com ). Accessed 23 September 2013.〕 For example, a paper presented in 1991 at a major international conference on this subject was titled: "The Prediction of Acid Rock Drainage - Lessons from the Database"〔Ferguson, K.D. and Morin, K.A. The Prediction of Acid Rock Drainage - Lessons from the Database. ''Proceedings: Second International Conference on the Abatement of Acidic Drainage.'' Sept 16 to 18, 1991, Montreal, Quebec.〕 Both AMD and ARD refer to low pH or acidic waters caused by the oxidation of sulfide minerals, though ARD is the more generic name. In cases where drainage from a mine is not acidic and has dissolved metals or metalloids, or was originally acidic, but has been neutralized along its flow path, then it is described as "Neutral Mine Drainage",〔(Global Acid Rock Drainage Guide (GARD Guide) ) INAP: The International Network for Acid Prevention. Accessed 23 September 2013.〕 "Mining-Influenced Water"〔Gusek, J.J., Wildeman, T.R. and Conroy, K.W. 2006. Conceptual methods for recovering metal resources from passive treatment systems. ''Proceedings of the 7th International Conference on Acid Rock Drainage (ICARD)'', March 26–30, 2006, St. Louis MO.〕 or otherwise. None of these other names have gained general acceptance. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Acid mine drainage」の詳細全文を読む スポンサード リンク
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