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Characterization of a Mine Waste Rock Pile with the DC Resistivity and Induced Polarization (DC-IP) Method
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 25th European Meeting of Environmental and Engineering Geophysics, Sep 2019, Volume 2019, p.1 - 5
Abstract
Mine waste rock piles (WRPs) can contain sulphidic minerals, whose exposure to oxygen and water can produce acid mine drainage (AMD). Since AMD generation and release is dependent on the volume and composition of waste rock, effective characterization of WRPs is desired for successful long-term AMD management. In this work, DC resistivity and induced polarization (DC-IP) were combined to characterize an AMD-generating WRP in Nova Scotia, Canada. 2D DC-IP imaging was first performed with 6 long survey lines to capture the full WRP landform. DC results indicated a highly heterogeneous and moderately conductive waste rock underlain by a resistive bedrock, while IP results identified several highly-chargeable regions within the waste, with normalized chargeability delineating regions specific to waste mineralogy only. 3D DC-IP imaging, with 17 parallel lines, was then performed on the pile plateau to focus on the composition of the waste rock. 3D DC-IP distributions identified coincident and continuous zones of low resistivity (<30 ohm-m) and high normalized chargeability (>0.4 mS/m), which were inferred as generated AMD (leachate) and stored AMD (sulphides), respectively. Hydrogeological, geological and geochemical information was used to validate the geoelectrical interpretations.