Application of a method to protect permanent mine workings by large pillars requires thorough analysis of geomechanical processes aimed at providing stability for a mine working during its long-term operation. The purpose of the paper is to study the processes of coal rock mass deformation to substantiate the selection of the protective pillar width. The examples to be considered are represented by mining-geological conditions of a central panel of PJSC Colliery Group “Pokrovske” where four permanent mine workings are planned to be driven. To substantiate the width of protective pillars, geomechanical stability of mine workings have been assessed in terms of the effect of stoping operations of the adjacent longwalls of the block and beyond their effect. It has been shown that insufficient dimensions of a support pillar result in considerable influence of stoping operations on the stability of permanent mine workings. Along with the increasing dimensions of a support pillar, the pressure in the rocks around the permanent inclined mine workings decreases, and the support load decreases as well. In terms of the appropriate dimension of the support pillar, the boundaries of the effect become smaller; the bolting and frame support provides completely the required mine working stability.

The causes of endogenous fires and methods to prevent coal spontaneous ignition were analyzed. Rational parameters of rock massif tamponage with different polymeric chemical compositions for stabilization of its stress-strain state and isolation of mine workings from methane penetration and fresh air leakage were investigated by the mine experimental methods. The dependences of the nominal pressure of injection of the chemical composition into the rock massif were established with taking into account coefficients of influence of rock type and stress concentration in the zones unloaded from rock pressure, in zones of geostatic pressure and in stress concentration zones. In order to control any accidental leaks of chemical composition through the main cracks, the stress-strain state of the rock massif in the mined area is taken into account for calculating the volume of substance to be injected. The parameters of methods for the rock massif cementation and tarring around the isolating bulkhead are substantiated. The method is developed for constructing a double isolating bulkhead in difficult mining and geological conditions to isolate the mined-out areas in the coal seams prone to spontaneous ignition.

Purpose of the research was to improve efficiency of underground gas drainage from the rock-coal massif. It is substantiated that most promising solution of the problem of increasing efficiency of gas drainage from the massif is to mine additional gas-drainage road. This approach allows separating processes of coal mining and methane recovery in space and time. The Ukrainian normative documents is recommended to mine the road behind zones with high rock pressure. We found that in difficult conditions of coal seam mining, distance from road to working long wall would be more than 100 m. This distance reduces efficiency of gas drainage and is not economically feasible due to significant length of gas-drainage boreholes and air breakthroughs. Therefore, gas-drainage road should be located as close to the working long wall as possible, but with possibility to ensure its stability during its entire service life. Experimental studies were conducted in Zasyadko Mine and Krasnolymanska Mine. It is established that with increasing distance from working wall to the gas-drainage road location in the massif, unloaded by the under working displacement, the road contour decreases, and methane flow rate increases in power dependencies. Use of these results will make calculation of the gas-drainage road rational location more accurate.