Ambient noise Love wave tomography at a gold mine tailings storage facility

Tailings storage facilities (TSFs) are some of the most challenging structures to operate in the mining industry. Some of these structures are susceptible to liquefaction and piping failure, and need to be monitored carefully. In this study, ambient seismic noise interferometry is applied to image the internal structure of a tailings storage facility (TSF) that showed signs of increased seepage. Twenty geophones were deployed along a roughly 100 m section of the TSF and recorded continuous seismic data. The ambient noise was used to create Love wave dispersion curves between sensor pairs, which were in turn inverted to estimate the shear wave velocity of the dam wall as a function of depth. The velocity profile indicated the phreatic surface roughly 10 m below the surface, with regions near the centre of the array showing the phreatic surface as close as 3 m below the surface. These areas are spatially well correlated with the area where increased seepage was identified and the results were comparable with cone penetration tests that were performed in the area. The study showed that the analysis of ambient seismic noise can be a cost-effective, fast and non-invasive method to image the internal structure of TSFs.