ACID MINE DRAINAGE
Clearwater Group has evaluated mine properties for resource potential, tax value for estate purposes, as well as for environmental issues. The firm has performed valuations of property with gold and silver resources as well as coal properties. The company has worked on mitigation measures to minimize acid mine drainage potential of sulfur-rich deposits.
Principal Geologist James A. Jacobs co-authored Acid Mine Drainage, Rock Drainage, and Acid Sulfate Soils (2014, Wiley).
The author is shown at the Richmond Portal of Iron Mountain Mine, a U.S. EPA Superfund Site with a documented -3.6 pH. Photos below show Iron Mountain Mine, with passive mitigation measures to treat acid mine drainage in the eastern U.S.
SIX ELEMENTS OF ACIDIC DRAINAGE AND IDENTIFICATION
The identification of the six elements of acidic drainage can be done by easily by professionals and interested persons with a modest budget of a few hundred dollars for laboratory tests. Most of the elements noted below can be identified by performing a site inspection.
1) Disturbance of pyrite-rich rocks; (identify pyrite with a hand lens and geology maps);
2) Aerobic conditions with oxygen in air and dissolved oxygen in water; (identify with a DO meter and a site inspection);
3) Microbial colonies which use pyrite as terminal electron acceptor for cellular respiration; (identify with a microbiological lab test);
4) Acidphile bacteria produce sulfuric acid (H2SO4) which lowers pH of drainage; (identify pH with a pH meter or pH paper and inspecting for visual evidence such as corrosion);
5) Acids dissolve toxic metals (Al, As, Cd, Mg, Mn, Pb, Zn, etc.) (identify metals with laboratory tests such as EPA Method 6020); and
6) Ecological and economic damage: such as fish kills, dead vegetation, habitat destruction, erosion, etc. (identify with a site inspection and reviewing regulatory reports and other documents and aerial photos).
Water treatment at Iron Mountain Mine relies on lime treatment as well as stormwater diversion.
Passive constructed wetlands have been used for acid mine drainage treatment.
Cold mix asphalt (CMA) can also be used to incorporate mining wastes into a recycled product.