Evidence Of Roof Collapse Detected On South African Coal Mines Using Sentinel-1 Interferometry

Surface subsidence associated with underground coal mining is a known concern due to the associated environmental as well as health and safety risks. This paper evaluates the potential of Sentinel-1 repeat-pass differential interferometry for monitoring mining-induced deformation. The area under investigation is a coal mining region in South Africa where pillar-extraction is taking place. The pillar extraction causes a weakening of pillars leading to roof collapse and subsequent deformation at the surface. The results of Sentinel-1 dInSAR analysis suggest that several deformation features could be observed during almost 2-years of monitoring and the evolution and progression of deformation basins over time could be studied. The results further indicate that operational monitoring of mining-induced deformation by Sentinel-1 interferometry would be possible assuming data continuity can be ensured. Since many mines are considering pillar-extraction as the end-of-life of the mine is reached, continued Sentinel-1 dInSAR observations can be incorporated into operational monitoring programmes.