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Formation and prevention of pipe scale from acid mine drainage at Iron Mountain and Leviathan Mines, California, USA

January 3, 2020

Pipelines carrying acid mine drainage (AMD) to treatment plants commonly form pipe scale, an Fe(III)-rich precipitate that forms inside the pipelines and requires periodic and costly cleanout and maintenance. Pipelines at Iron Mountain Mine (IMM) and Leviathan Mine (LM) in California carry acidic water from mine sources to a treatment plant and have developed pipe scale. Samples of scale and AMD were collected from both mine sites for mineralogical, microbiological, and chemical analysis. The scale mineralogy was primarily schwertmannite with minor amounts of poorly crystalline goethite. Although the bulk composition of the scale was similar along the length of the pipeline at IMM, the number of iron-oxidizing bacteria and concentrations of associated trace elements decreased along the flow-path inside the pipeline. Laboratory batch experiments with unfiltered AMD from IMM and LM showed that Fe(II) oxidation was driven by microbial activity when the pH was <5. A remediation strategy of decreasing the pH to <2.2 was tested through geochemical modeling and laboratory experiments. These experiments indicated that scale formation could be prevented by decreasing the pH, which could be achieved at IMM by mixing source waters. However, the presence of Fe(III)-rich scale in a pipeline buffers the pH to higher values that may affect the efficacy of this remedial approach.

Citation Information

Publication Year 2020
Title Formation and prevention of pipe scale from acid mine drainage at Iron Mountain and Leviathan Mines, California, USA
DOI 10.1016/j.apgeochem.2020.104521
Authors Kate M. Campbell, Charles N. Alpers, D. Kirk Nordstrom
Publication Type Article
Publication Subtype Journal Article
Series Title Applied Geochemistry
Series Number
Index ID 70208716
Record Source USGS Publications Warehouse
USGS Organization California Water Science Center