Assessment of the Geoavailability of Trace Elements from Minerals in Mine Wastes: Analytical Techniques and Assessment of Selected Copper Minerals By Rhonda Driscoll, Phillip Hageman, William Benzel, Sharon Diehl, David Adams, Suzette Morman, and LaDonna Choate Scientific Investigations Report 2011-5211 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior KEN SALAZAR, Secretary U.S. Geological Survey Marcia K. McNutt, Director U.S. Geological Survey, Reston, Virginia: 2011 About USGS Products For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS About this Product Publishing support provided by Denver Science Publishing Network For more information concerning this publication, contact: Center Director, USGS Central Mineral and Environmental Resources Science Center Box 25046, Mail stop 973 Denver, CO 80225 (303) 236-1562 or visit the Central Mineral and Environmental Resources Science Center Web site at: http://minerals.cr.usgs.gov Suggested citation: Driscoll, Rhonda, Hageman, Phillip, Benzel, William, Diehl, Sharon, Adams, David, Morman, Suzette, and Choate, LaDonna, 2011, Assessment of the geoavailability of trace elements from minerals in mine wastes: analytical techniques and assessment of selected copper minerals: U.S. Geological Survey Scientific Investigations Report 2011-5211, pamphlet, 68 p. 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Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Sample Preparation .......................................................................................................................................2 Introduction............................................................................................................................................2 Preparation Method .............................................................................................................................2 Mineralogical Analyses ................................................................................................................................3 Introduction............................................................................................................................................3 Methods..................................................................................................................................................3 Results ....................................................................................................................................................5 Carbonate Minerals Azurite and Malachite ............................................................................5 Sulfide Minerals Chalcopyrite and Bornite ...........................................................................10 Summary...............................................................................................................................................24 Bulk, Leachate, and Acid-Base Accounting Geochemical Study of Four Copper-Bearing Minerals ...........................................................................................................................................25 Introduction—Bulk Sample Chemistry.... ........................................................................................25 Bulk Sample Digestion Methods ......................................................................................................25 Bulk Chemistry Summary...................................................................................................................25 Introduction—Leaching Studies ......................................................................................................26 Laboratory Leaching Methods and Sample Analysis ...................................................................28 Leachate Geochemistry .....................................................................................................................28 Leachate pH ................................................................................................................................28 Leachate Specific Conductance (SC) ....................................................................................28 Major Anions by Ion Chromatography ............................................................................................29 Alkalinity ......................................................................................................................................29 Leachable Copper ......................................................................................................................29 Summary of Leaching Studies ...................................................................................................................30 Acid-Base Accounting (ABA) Study .........................................................................................................32 Summary of Acid-Base Accounting Study ..............................................................................................32 Leachate pH as an Indicator of Acid-Base Potential ............................................................................33 In Vitro Bioaccessibility Extractions .........................................................................................................34 Introduction..........................................................................................................................................34 Methods................................................................................................................................................34 Ingestion Pathway .....................................................................................................................34 Inhalation Pathway ....................................................................................................................35 Cell-Carrier Fluid ........................................................................................................................35 Results ..................................................................................................................................................35 Discussion ............................................................................................................................................40 Limitations of Results .........................................................................................................................43 Summary...............................................................................................................................................43 Procedure for Determination of Metal Toxicity Using MetPLATETM ....................................................44 Introduction..........................................................................................................................................44 General Method ..................................................................................................................................44 Summary...............................................................................................................................................45 Conclusion.....................................................................................................................................................49 Selected References ...................................................................................................................................50 iv Figures 1. Photographs of intergrown azurite and malachite .........................................................................6 2. X-ray diffraction scans of azurite .......................................................................................................7 3. Semi-quantitative mineralogy for azurite .........................................................................................9 4. Unit cell model for azurite..................................................................................................................10 5. Thin-section micrographs of malachite ..........................................................................................11 6. X-ray diffraction scan of malachite .................................................................................................12 7. Semi-quantitative mineralogy for malachite ..................................................................................13 8. Unit cell model for malachite ............................................................................................................14 9. Reflected-light micrographs of malachite ......................................................................................15