DC RESISTIVITY AND IP METHODS IN ACID-MINE DRAINAGE PROBLEMS - RESULTS FROM THE COPPER-CLIFF MINE TAILINGS IMPOUNDMENTS

Oxidation of sulfide minerals in the mine tailings impoundments at Cop per Cliff, Ontario generates acidic conditions and elevated concentrat ions of dissolved metals and sulfates in the pore water. The pore wate r migrates away from the tailings to pose a potential environmental ha zard if it should reach nearby water systems. There is a need to chara cterize this potential environmental problem and to assess the future hazards. A combined DC resistivity and induced polarization (IP) surve y was carried out along one of the major flowpaths in the tailings and the data were inverted to produce detailed electrical conductivity an d chargeability structures of the cross-section below the survey line. The conductivity distributions are directly translated, through theor etical and empirical relations, to a map of the concentration of the t otal dissolved solids (TDS) along the cross-section and thereby provid e insight about the in-situ pore water quality. The sulfide minerals a re the source of the IP response and, thus, when combined with borehol e data, the chargeability model can be used to estimate the amount and distribution of the sulfides.