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Predictive Experiments of Sulfide Oxidation Processes

Project status is complete. Please check the CRMRSC project list for currently active projects.

Project Objectives

The objective of our work was to understand and ultimately quantify the behavior and distribution of environmentally significant elements as they are dispersed from their sources through the environment. Sources of elements in mineralized terranes include natural and anthropogenic entities such as ore deposits, mine tailings, and waste rock. Characterization of these source materials involved identifying the solid phases where the toxic elements reside, the speciation of the toxic elements (e.g., oxidation state and type of bonding to the mineral structure), and the rates and mechanisms of release from the mineral structure. Once released from their sources, physical, inorganic, and biogeochemical processes act to re-distribute and transform both dissolved and particulate forms of the elements.

Our specific objective was to determine rates and mechanisms of sulfide mineral oxidation and toxic element release due to chemical and microbiological processes. Laboratory experiments conducted in the last decade have determined the rates of inorganic oxidation of some common sulfide minerals under certain ranges of conditions, but much more needs to be done, especially with alteration of specific minerals and chemical reactions mediated by microorganisms. In addition, little has been done experimentally to determine the behavior of potentially toxic trace elements that exist as intergrown refractory minerals and non-sulfide mineral inclusions (usually silicates or oxides), in discrete inclusions of sulfides or sulfosalts, in defect sites, or in solid-solution within the host minerals. Trace minerals containing toxic elements may have very irregular distribution in the host sulfides. This project conducted experimental reactions of fully characterized natural sulfide minerals and will be fully integrated and interactive with pertinent Mineral Resource Program field investigations. These data were incorporated into geochemical reaction models in the form of reaction rates, solidsolution activity coefficients or specific interaction models, distribution coefficients, sorption models, and thermodynamic stability of minor or secondary phases. New fundamental information was made available to be utilized in geochemical and biogeochemical reaction progress calculations for specific field sites to provide a predictive capability of environmental behavior of ore deposits.

Relevance & Impact

This Project advanced the development and application of geoenvironmental mineral deposit models by identifying the processes that control environmental signatures of mineral deposits and the fate of metals in the environment. The studies supported the development of predictive models necessary for future mineral-environmental assessments, and provided the private sector and government agencies involved in regulatory and stewardship activities with the tools to make informed and rational decisions about (1) land use before exploration and mining and (2) post-mining remediation.

Additional work continued in the Modeling Near-Surface Processes in Mineral Systems project.

Products

Posters Delivered

• Seal R.R., Hammarstrom, J.M., Piatak, N.M., and Balistrieri, L.S., 2004, Environmental geochemistry of drainage from the abandoned Elizabeth Cu mine, USA: poster, Eleventh International Symposium on Water Rock Interaction.
• Koski, R.A., Stillings, L.L., Shanks, W.C. III, Munk, LeeAnn, Nelson, S.W., and Chezar, Henry, 2003, Metal-sulfide oxidation in coastal environments of eastern Prince William Sound, Alaska: Geological Society of America Abstracts with Programs, v. 35, no. 6, p. 239-240.
• Munk, LeeAnn, Nelson, S.W., Kennish, J.M., Munk, Jens, Aston, M.C., Koski, R.A., Shanks, W.C. III, Stillings, L.L., and Chezar, Henry, 2003, Metal and trace element distribution in water and streambed precipitates generated from weathering of copper sulfide tailings, Latouche island, Prince William Sound, Alaska: Geological Society of America Abstracts with Programs, v. 35, no. 6, p. 239.
• Shanks, W.C., Munk, LeeAnn, Stillings, L.L., Koski, R.A., Nelson, S.W., and Chezar, Henry, 2003, Sulfide mineral oxidation and metal flux in the intertidal zone, Ellamar Mine, Prince William Sound, Alaska: Geological Society of America Abstracts with Programs, v. 35, no. 6, p. 240.

Presentations Delivered

• Balistrieri, L.S. and Tempel, R.N., 2003, Modeling physical and biogeochemical processes in Dexter Pit Lake, Tuscarora, Nevada: Abstracts Geological Society of America Annual 2003 Meeting.
• Proceedings of the Western Region Restoration of Abandoned Mines Sites (RAMS) workshop on GIS and Technology References Databases. January 7-8, 2002, sponsored by the Mining Life-Cycle of the Mackay School of Mines, University of Nevada, Reno.
• Seal R.R., Hammarstrom, J.M., Piatak, N.M., and Balistrieri, L.S., 2004, Relationship of geologic and hydrologic setting to distinct evolutionary paths of mine drainage at the Elizabeth copper mine Superfund site, Vermont: 2004 Geological Society of America Northeast Section (39th Annual) and Southeastern Section (53rd Annual) Joint Meeting.
• Seal, R.R., Balistrieri, L.S., Piatak, N.M., and Hammarstrom, J.M., 2003, Physical and chemical limnology of an acidic pit lake at the Elizabeth copper mine Superfund site, Vermont: Geological Society of America Annual 2003 Meeting.

Reports Delivered

• Koski, R.A., German, C.R., and Hein, J.R., 2002, Fate of hydrothermal products from midoceanridge hydrothermal systems: Near-field to global perspectives, in Halbach, P.E., Tunnicliffe, V., and Hein, J.R., eds., Energy and mass transfer in marine hydrothermal systems: Berlin, Dahlem University Press, p. 295-313.