Monitoring the effect of weather on settlement response of tailings by means of InSAR

Interferometric Synthetic Aperture Radar (InSAR) represents a satellite-based monitoring tool capable of tracking temporal changes in displacement over large areas. Due to its wide spatial coverage, InSAR monitoring has become an attractive tool in monitoring of tailings storage facilities (TSFs). InSAR measures the signal phase change between two images of the same area acquired at different times. The post-processed image of the signal phase change is represented by an interferogram. By combining multiple interferograms it is possible to generate a time-series of ground displacement, and maps showing cumulative or average displacement. By combining post-processed Sentinel-1 satellite data and historical weather reports obtained from the Australian Bureau of Meteorology, this paper presents the effect of seasonal changes (i.e., precipitation, temperature) on the settlement and swelling of tailings within a TSF. Trends in variations of negative and positive displacements over a period of several years as captured by InSAR data are presented. It is observed that, generally, the highest settlement rate of change occurred during the months marked by heavy rainfall. These could be the result of consolidation due to downward seepage into desiccated tailings. The hotter and drier months undoubtedly desiccated the tailings, but no change in settlement may be attributed to temperature variation.