GAS CONTENT OF A COAL SEAM FACE AREA DURING THE HIGHPERFORMANCE EXTRACTION SECTION OPERATION
The article proposes to determine the seam gas content depending on normal stresses. Estimated stresses in the edge of the coal seam, which is worked out by long extraction face, as well as the corresponding values of the gas content of the seam face area, which is confirmed by the coal samples' selection in the longwall and their processing. It is shown that during the advance movement of a long working face, the gas content of the beaten coal strip is lower than the gas content of the seam in rock massif untouched by mining operations. The decrease in stress in the seam causes its degassing. Moreover, stress reduction begins at a distance equal to half of the longwall length, which is determined by the structured pattern of the undermined rock mass. Due to this, the gas content in the crushed coal strip is lower than natural, indicated on mining plans by 10-30%. The magnitude of the reduction in gas content depends on the geological and technological conditions of mining.