How to Prevent Acid Mine Drainage
Acid mine drainage (AMD) is one of mining's most serious threats to water and aquatic life. It occurs due to the outflow of acidic water from usually abandoned coal or metal mines. When sulfide-rich metal ores are exposed to water and oxygen, sulfuric acid is formed. The resulting acid then runs off as acid mine drainage. However, AMD can be curbed before it causes any harm.
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Instructions
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Flood and seal underground mines with water. Locate and seal all shafts, adits and possible openings where there might be a influx of oxygen-containing water. By flooding the mine, oxygen--which perpetuates AMD formation--will be consumed by microorganisms and mineral-oxidizing agents present in the mine to prevent AMD production.
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Create a benign composite by blending acid-generating and acid-consuming materials. Add solid-phases of phosphate like apatite to pyrite mine waste to precipitate iron as ferric phosphate. This measure minimizes AMD formation since it reduces the chance of sulphide minerals becoming oxidized.
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Cover surface storage of reactive mineral spoilings with a dry "sealing layer" made from clay. This layer will completely prevent the reactive spoilings from coming in contact with any form of oxygen and water that will lead to the formation of AMD in surface mining areas.
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Apply biocides such as sodium dodecyl sulfate (SDS)--a type of highly toxic anionic--to inhibit lithotrophic (rock-eating) and sulphur-oxidizing bacteria in mineral spoils and tailings. Since the activities of these organisms play an important role in acid drainage formation, applying the biocides can kill them off and help prevent AMD formation.
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References
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- Photo Credit Mine image by Eldin Muratovic from Fotolia.com
