Effect Analysis On Pressure Relief And Applicationg In Pressure-relief Gas Extraction For Protection Seam Mining Of Thick Coal Seam

Coal and gas outburst is a complicated dynamic phenomenon, the coal mine is coal akind of serious natural disasters, it seriously threatens the safety of mine productionand safety of personnel. The protective layer is a regional mining of coal and gas outburstprevention measures most cost-effective. Coking coal company three levels and threestages after entering deep mining, upgrade for the outburst coal, according to coalseam conditions,determination of gas geology rule of basic parameters of gas test area ofcoal seam. Ultimately determine the3#coal seam mining as a protective layer,4#，5#coalmining as conducted by a protective layer of coal and gas outburst regional conflictprevention measures.After the order to accurately grasp the overlying3#coal seam as a protective layermining, to cover the protective effect of4#,5#coal seams and validation of the scope ofprotection, the need for deep mining conditions of investigation and verification,reasonable parameters for protection protective layer mining to provide scientific basis forcoking coal company. In this paper, the thick coal seam group Shitanjing protective layer3#coal mining face Ⅲ10303, analysis, numerical simulation strike, dip extent of relief,and other parameters affecting the scope of the theory, a comprehensive analysis of the useof these parameters to determine the appropriate scope of relief. Industrial test site throughtheory and simulation parameters are arranged after the protective layer protective layermining effectiveness analysis relief holes and pressure relief gas drainage holes, to studythe protective layer is a protective layer in the mining strike and dip direction of the reliefeffect, the scope of protection.Throughout the test area to choose the appropriate drilling site layout, the determinationof the protective gas flow rate, gas content, permeability coefficient, and use the industrialanalysis and adsorption constants a and b values calculated by muir long formula, gaspressure, the relative deformation of coal seam and other parameters for the analysis ofprotective layer mining effect, the scope. Through the field experiment, the result analysis of the actual scope of pressure relief and basic conforms to the theory and simulation;According to the investigation results, the carboniferous coal mine on the protective layer3#coal seam mining are protective layer4#coal seam deformation stability after the relativeexpansion deformation of17.74‰, coal seam permeability coefficient increases1050times, coal seam gas extraction rate was70%, and the coal seam gas pressure from0.97MPa to0.26MPa, gas content decreased from11.91m3/t to3.48m3/t, eliminate theoutburst danger. In addition, according to the site visits to verify the test, that thetheoretical analysis, numerical simulation and industrial test methods such conclusions arereliable and reasonable, providing engineering of reference for the company’s future cokingcoal deep mining.