Detection, Localization and Backfill Assessment of Old Mining Shafts in the Upper Silesia Coal Basin with Geophysical Me

The old shafts can create serious hazards for safe use of post mining lands. They complicate engineering conditions and need special geotechnical solutions to be applied when have to serve as structures bedrock. The paper describes experiences from application of various geophysical methods for old shafts detection and characterization. It concerns mostly gravity surveys that are compared with supplementary resistivity and GPR surveys, conducted on areas of abandoned coal and ore mines in the Upper Silesia Coal Basin (UCSB - Poland.). As an introduction to applications several geophysical models of post mining subsurface structures are described and discussed.