HR: 1340h
AN: B33A-1014    [Abstracts]
TI: Natural Carbon Sequestration in Mine Tailings
AU: * Wilson, S A
EM: swilson@eos.ubc.ca
AF: Department of Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4 Canada
AU: Dipple, G M
EM: gdipple@eos.ubc.ca
AF: Department of Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4 Canada
AU: Raudsepp, M
EM: mraudsepp@eos.ubc.ca
AF: Department of Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, BC V6T 1Z4 Canada
AU: Anderson, R G
EM: Bob.Anderson@nrcan-rncan.gc.ca
AF: Geological Survey of Canada, 101-605 Robson Street, Vancouver, BC V6B 5J3 Canada
AB: We have documented active sequestration of atmospheric carbon dioxide (CO2) in chrysotile mine tailings at Clinton Creek, Yukon and Cassiar, British Columbia. Hydrated magnesium carbonate minerals develop in mine tailings as a natural consequence of the weathering process within the residues. Magnesium, leached from minerals, reacts with dissolved CO2 in rainwater, precipitating carbonates at the surface of tailings upon evaporation of pore fluids. Increased reaction rates are observed in the tailings environment due to fine grainsize resulting from mineral processing. Mine tailings may therefore represent the optimal environment in which to pursue mineral sequestration. X-ray powder-diffraction studies demonstrate that CO2 is crystallographically bound within the hydrated magnesium carbonate minerals nesquehonite, dypingite, hydromagnesite, and lansfordite. Quantitative phase analysis with X-ray powder-diffraction is used to determine the modal abundance of hydrated magnesium carbonates in mine tailings. An atmospheric source of CO2 is confirmed with stable and radiogenic carbon isotope techniques. Serpentine and olivine-rich tailings are produced by many types of mining, including nickel, diamond, platinum, and chrysotile. The global scale of these mining activities has a sequestration capacity on the order of 100 million tonnes of carbon per year. Widespread implementation of mineral sequestration in mine tailings has the potential to render large mining operations greenhouse gas-neutral and significantly reduce CO2 emissions on a global scale.
DE: 0428 Carbon cycling (4806)
DE: 1039 Alteration and weathering processes (3617)
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 3665 Mineral occurrences and deposits
SC: Biogeosciences [B]
MN: Fall Meeting 2005