Geophysical characterization of an undrained oil sands tailings pond dyke was conducted at Syncrude Canada’s Southwest Sand Storage Facility (SWSS). Push tool conductivity (PTC), electromagnetic (EM), and electrical resistivity tomography (ERT) methods in tangent with hydrogeological and chemistry measurements were used to investigate soil moisture, hydraulic heads, and groundwater salinity distributions. Geophysical data were collected from 2001 to 2008 and interpretations can further be used to validate studies of groundwater flow and salt transport within the structure. An Archie’s Law petrophysical model was used to relate measured bulk conductivity, from geophysical surveying, with measures of soil moisture and fluid electrical conductivity. It was found that a relatively strong relationship between bulk electrical conductivity and soil moisture exists, while weak to no correlation was observed between bulk and fluid electrical conductivity. ERT surveying was capable of clearly identifying the location of the capillary fringe within the dyke. This study provides a unique look into the application of geophysical techniques to investigate soil moisture, hydraulic head, and salt distribution in an active undrained tailings dam structure. The methodology and insights gained from this study may be applied to similar undrained and drained oil sands tailings storage sites.

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