Spatio-temporal analysis of ground subsidence due to underground coal mining in Huainan coalfield, China

Underground coal mining produces ground subsidence that adversely impacts the environment. Huainan coalfield, one of the largest coalfields in East China, experiences fast ground subsidence that restricts agricultural, urban and rural developments in this region. We used stacking and the small baseline subset interferometric synthetic aperture radar (InSAR) techniques to perform a spatio-temporal analysis of ground subsidence in Huainan coalfield caused by underground coal mining activities. Fourteen L-band ALOS PALSAR images acquired during 2007–2010 were used to retrieve high-resolution and high-precision time series of ground deformation and the mean deformation rate. The results show that subsidence with a rate of up to 15 cm/year is widely spread over the studied area in response to mining operation. In regions where mining lasted for many years, ground subsidence continues at a steady rate during the entire observation period. In regions of recent (i.e., since 2007–2009) mining activities, ground subsidence is rapidly accelerating. Accumulated subsidence already caused submerging of the agriculture lands, limiting further mining activities and farming. The InSAR results are consistent with the ground leveling measurements and observations. It is confirmed that the L-band InSAR can be successfully utilized for mapping long-term subsidence in Huainan coalfield in China caused by underground coal mining activities.