Detection of surface subsidence using SAR SENTINEL 1A imagery and the DInSAR method – a case study of the Belchatow open pit mine, Central PolandJaroslaw Wajs and Wojciech J. MilczarekE3S Web Conf., 55 (2018) 00004DOI: https://doi.org/10.1051/e3sconf/20175500004