Nordstrom DK, Alpers CN.. Negative pH, efflorescent mineralogy, and consequences for environmental restoration at the Iron Mountain Superfund site, California. Proc Natl Acad Sci USA 96: 3455-3462

United States Geological Survey, 3215 Marine Street, Boulder, CO 80303-1066, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 04/1999; 96(7):3455-62. DOI: 10.1073/pnas.96.7.3455
Source: PubMed


The Richmond Mine of the Iron Mountain copper deposit contains some of the most acid mine waters ever reported. Values of pH have been measured as low as -3.6, combined metal concentrations as high as 200 g/liter, and sulfate concentrations as high as 760 g/liter. Copious quantities of soluble metal sulfate salts such as melanterite, chalcanthite, coquimbite, rhomboclase, voltaite, copiapite, and halotrichite have been identified, and some of these are forming from negative-pH mine waters. Geochemical calculations show that, under a mine-plugging remediation scenario, these salts would dissolve and the resultant 600,000-m3 mine pool would have a pH of 1 or less and contain several grams of dissolved metals per liter, much like the current portal effluent water. In the absence of plugging or other at-source control, current weathering rates indicate that the portal effluent will continue for approximately 3, 000 years. Other remedial actions have greatly reduced metal loads into downstream drainages and the Sacramento River, primarily by capturing the major acidic discharges and routing them to a lime neutralization plant. Incorporation of geochemical modeling and mineralogical expertise into the decision-making process for remediation can save time, save money, and reduce the likelihood of deleterious consequences.

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Available from: Darrell Kirk Nordstrom
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    • "Nordstrom and Alpers [1] describe the reactions involved in the origin of an AMD from pyrite oxidation through three steps: "

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    • "In these locations pH has a considerable effect on the availability and, as a consequence, the toxicity of heavy metals (Mason and Jenkins 1995). Acidic environments tend to contain unusually high concentrations of heavy metals, because their solubility increases markedly as the pH decreases (Nordstrom and Alpers 1999). Despite these extreme environmental conditions, a large number of prokaryotic and eukaryotic organisms have been identified living in the presence of high concentrations of heavy Abstract High concentrations of heavy metals are typical of acidic environments. "
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    • "related with both working and abandoned mining operations . Mineral extraction and beneficiation produce crushed, milled waste rock deposited in tailings causing a potential risk to the environment when exposed to weathering (Nordstrom and Alpers 1999; Dold and Fontboté 2001). They act as a major contributor to environmental pollution, providing sources of heavy metals that may lead to the contamination of the surrounding soils, agricultural areas and villages through weathering (wind erosion, water runoff, and leachates) (Conesa et al. 2006; Navarro Flores and Martínez Sola 2010; Navarro et al. 2008; Chaoyang et al. 2009; Vrhovnik et al. 2011; Bes et al. 2014; Mileusnić et al. 2014,, Kříbek et al. 2014). "
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