STABILITY ASSESSMENT OF COAL-AND-ROCK MASS AROUND TEARDOWN ROOM IN THE YALEVSKY MINE

In terms of the mining conditions in longwall No. 52-13 in coal seam 52 in the Yalevsky Mine, the integrated research aimed at geomechanical assessment of rock mass stability around a teardown room is carried out. The stress-strain analysis of the geotechnical structure in the extraction panel was implemented by 3D finite element-based modeling. Owing to this, the geological conditions of the coal occurrence and the structural complexity of geotechnical objects were taken into account to the maximum extent in the calculations, which allowed near-reality results qualitatively and quantitatively consistent with in-situ data. The forecast maps of stress distribution in the elements of the mining system in the extraction panel are obtained with regard to the earlier mined-out areas, using the gravitational model of the geomedium. Me localities and sizes of the post-limiting deformation zones (possible instability zones) are determined in coal-and-rock mass around underground excavations. It is found that safety of the teardown room and the adjacent drainage and ventilation drives is mostly governed by the poor quality and jointing of the coal-and-rock mass. The predictive estimate of the rock mass stability provides a complete idea on the mechanism of deformation and failure of rocks in the structural elements of the analyzed drive, which enables reasoned design of the support system for the teardown room, as well as the drainage and ventilation drives while combining safety and efficiency of removal of the powered roof support units.