Peculiarities of mining the protecting pillar in the laminal massif of soft rocks

Purpose. Increasing the completeness of mining coal reserves from protecting pillars located in a laminal massif of soft rocks in the roof and bottom in order to reduce the coal losses in mines and horizons in case when mining operations are at the stage of completion. Methodology. A geomechanical model is developed for research into mining of protecting pillars influenced by stope works, taking into account the laminal massif and rheological processes of creep deformations and stress relaxation of the rock massif. Numerical modelling and analysis of the stress­strain state of the massif are conducted. Conclusions are drawn in terms of sub­ stantiation of the technical solutions for mining the protecting pillars. findings. New patterns have been determined of the stress­strain state of a laminal rock massif in the zone influenced by stope works. A geomechanical model has been developed for mining the protecting pillars with account of rheological processes in the rocks, and the technological parameters of mining the coal from longwall faces have been substantiated. A possibility is provided for repeated use of mine workings by introducing a resource­saving fastening system. originality. The patterns have been determined of the frontal bearing pressure zone displacement ahead of the longwall face during mining the protecting pillars, as well as the concentration factor Ky = 1.1–1.3 at a height from the c6 coal seam up to 18– 20 m, when contacting the thick siltstone. It was found that the calculated compressive resistance is by 4.2 times higher than the