Increased productivity and safety of European coalmines through advanced techniques, knowledge and planning tools enabling strata control of the face-roadway junction (PROSAFECOAL) : final report

By reviews and examinations, basic data on current face end support design practices, experiences with cable-bolting, 2D-modelling and mine layouts were compiled and evaluated. They vary widely across Europe. A wide range of improved and new support systems were tested and the results incorporated into the NIOSH STOP programme and a handbook. A triaxial test cell for a new cable bolt testing bench was built and used. Geotechnical investigations were carried out, such as load and stress measurements, surveys of geological and geotechnical characteristics (especially joints and fractures) and gob reconsolidation, over a wide range of European mines. Interactions were evaluated (geology, joints systems and properties, seam structure, excavation methods, support design), methodologies developed concerning gob reconsolidation and support under caving gobs, and a shear test apparatus was built and used. Through these results, novel numerical 3D-modelling tools (FLAC-3D) for support elements and mine layouts' inclusive face-roadway junctions could be developed, calibrated, applied and validated. This complex and highly automated model is universally applicable for all roadway types usual in Europe and for a large number of support elements. Due to short modelling and calculation times, it is now possible to use 3D-modelling as a standard feature for underground mine planning. A logical tree was developed in which improved support management systems from German, Polish and British coal mine types were integrated. This could enable users to define a methodology tailored to the actual conditions of a mine. Improved support design and management was developed and successfully tested, including at multi-slice longwall extraction.