Influence of rock shear processes on the methane content of longwall faces

Purpose. To establish patterns of change in methane content during formation of zones of unloading of rock mass caused by a longwall face progression. Methodology. Determination of gas content (methane content) of coal seams, ash content of Karaganda basin coals, methane content of mine workings was made on the basis of taking and cutting samples from the coal massif in the laboratory of “Management of special maintenance and gasification” of the Coal Department of JSC “Qarmet” according to the DMT methodology (Germany). The chemical structure of gases of k10 seam was determined in the laboratory of Scientific Research Center “Ugol” (Karaganda), as well as by samples of air-gas mixture of degassing wells and in the working area of Saranskaya mine. Findings. A model of geomechanical structurization of rock massif was developed, patterns of methane content changes were established, obtained in specific mining-technological conditions of the mine, which were used for productive and safe work on coal excavation. Originality. For the first time a model of geomechanical structurization of the coal-rock massif in the conditions of longwall faces was developed; a parametric model determining the intervals of the mining pillar to increased methane flows into the mined-out space was developed; a connection between the dynamics of geomechanical processes in the mined-out coal-rock massif and the methane content of the mine face was established. Practical value. The established regularities of change in methane content of mining pillar areas arising at rock shear make it possible to plan degassing of mining area, to provide safe working conditions for miners on gas factor, to forecast the moment of formation of the main roof vaults of different levels and methane emission into the mine face to control mining, which were tested at Saranskaya mine Coal Department of JSC “Qarmet”.