Influence of Stress Variation in Roof Rocks of Coal Seam on Strata Gas Conditions in Longwalling

Mining of a horizontal isolated seam in a uniform medium in plane strain conditions is considered. The stress distribution in roof rocks of the coal seam is obtained at different stages of mined-out area development. The stresses are governed by the complex-variable function, which allows determining location and configuration of zones of stress relaxation and additional load in rock mass. This information is required for estimation of induced jointing and formation of gas pockets in the coal seam parting. The use of the analytical solution makes it possible to obtain relations for finding stress concentration factors and to present the related parameters as contour lines.