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.

Purpose. Working out measures providing safe application of a shock blasting mode while driving workings in outburst-prone coal seams. Methods.Conveying of shock blasting at the mine workings on the coal mines of Ukraine is regulated by a number of specification documents. At the same time, in the process of shock blasting production numerous technological violations of the mode take place and there are often gas-dynamic phenomena, including those with death of people. The mode of shock blasting at mines is used for unworked coal breaking on outburst-prone seams regardless of results of prognosis and efficiency of antilanding measures done, at troublesome seams in the zones where the reading "prone" is set by latest estimate; and while driving in outburst-prone coal seams.Findings. Shock blasting is used at mines at mines in rather wide range of mining and geological conditions. It is recommended to apply the methods of intensity and frequency of gas and oil emissions attenuation at shock blasting on especially outburst-prone layers. The methods of depth increase of pre-face part of a coal bed unloading zone are used. The increase is achieved by means of heading rock loosening of adjacent strata, advanced blasting, blast hole charge operation in adjacent strata, front-rank loosening (camouflet blasting) of coal bed. Moreover, the blasting pattern with formation of piled blocking retaining wall is applied.Originality. The main scientific and technical principles of the safe and efficient use of a shock blasting mode in blast hole drilling driving in outburst-prone coal seams and beds are formulated. Practical implications.Applying shock blasting mode in mine workings conveying proved to be one of the safest methods to prevent gas-dynamic phenomena. Simultaneously, as a rule, this method is one of the most costinefficient methods especially when paced work of coalmine is vital. Therefore, basic research directions are to be continued towards reduction of expenses and increase of this method application efficiency.

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An algorithm for calculating the Volmer diffusion coefficient of methane adsorbed in coal in the bottomhole zone of the formation to the maximum reference pressure is developed with taking into account the change in the Folmer porosity and the size of the space of this zone. The algorithm is based on the using of the exponential law of compression, which describes the structural changes in the reference pressure of the coal seam. This allowed us to determine the diameter of the Folmer pores in the study area depending on its stress state. Based on these data and the calculation of the exponential nature of the change in porosity, the regularity of the Folmer diffusion in the bottomhole region at its fixed length and initial porosity of coal is established. By using a method of step-by-step approximating the solution of this problem for different parameters, the research results are generalized to the existing ranges of change in the Folmer porosity of coal and the size of the bottomhole region of reference pressure in mining conditions at great depths. The functional approximation dependence is established, which allows to perform calculations of the Volmer diffusion coefficient of methane desorbed from the coal layer, with simultaneous change of two parameters - initial porosity of coal and distance between the bottom to the maximum reference pressure zone. Calculations showed that when reference pressure approached its maximum at a distance of up to 10 m from the face the coefficient of Folmer diffusion of methane in coal decreased slightly. In this case, there is a strong dependence of the Volmer diffusion coefficient on the diameter of the Folmer pores in the virgin coal layer. For example, when this diameter increases twofold - from 8 А to 16 А at the distance of 20 m from the face to a maximum reference pressure, the coefficient of Folmer diffusion increases by 1.5 times. That is, Folmer's diffusion is the most intensive in the disturbed zones of the coal layer. This can be the area of maximum reference pressure, if there is a zone of disintegration, or in that part of the face zone, which is characterized by the developed system of fractures. Key words: adsorbed methane, coal layer, face zone, Folmer pores, Folmer diffusion coefficient.

Purpose. Study the adsorption equilibrium of adsorbed during the generation of methane in coal massif to determine the conditions for its implementation at different depths of mining operations. Methods. The thermodynamic research methodology, numerical calculation methods, mathematical processing of research results using approximation methods. Results. The entropy change of the «adsorbed methane – coal» system shows that the initial state of adsorbed methane during its generation in a coal seams determined by the depth of the seam and the degree of filling of its pores with methane. The results of the calculation showed, that the sorption equilibrium of the “methane – coal” system in the mountain massif is energetically most probable at the degree of filling of the pores with methane, which is θ = 40%. When θ < 40 % an irreversible spontaneous process of adsorption of methane by coal occurs, but when θ > 40% – its desorption, the degree intensity of which can be estimated by the ratio obtained in the work. It has been established that at the depth of the coal seam there is only low-intensity process, and at Н > 500 m – the process is more intensive. Therefore, when methane is generated at depths of Н < 500 m, it is likely that due to weak desorption and high sorption bond energy, the pores tend to be filled with methane almost completely. When Н > 500 m they tend to sorption equilibrium, so they are filled with methane by only 40%. The rest of the volume of gas generated in the coal seam at depths greater than 500 m, as a result of an intensive desorption process, migrates into the intervening rock seam. Scientific novelty. As opposed to a priori accepting opinions about what the initial state of methane adsorbed in coal is always characterized by the complete filling of pores with gas, numerical calculations dedicated to this issue have been performed for the first time in the paper. Calculations are based on modern ideas about the generation of methane in coal with the help of the separation of methyl group and hydrogen atoms from aliphatic fringes, which combine to form methane molecules. At the same time, the dependence of the change in the entropy of the “adsorbed coal – methane” system on the depth of occurrence and the degree of filling of its pores with methane during the generation of methane in the coal seam has been established. Practical significance. The research results make it possible to obtain fundamentally new regularities of the processes of mass transfer and filtration of methane in the mountain massif at great depths. The use of new laws makes it possible to adjust the existing technologies of mine ventilation and methods of safe mining operations in emission-hazardous and highly gas-bearing coal seams, to develop fundamentally new technologies in this direction, as well as to make more accurate calculations of methane reserves in various rocks of the mountain massif.