Study On The Protected Range And The Law Of Gas Migration Of Upper Protective Coal Seam With Closed Distance

Coal-gas outburst is one of the most seriious disasters in mine production. Themost effctive and economical regional prevention measure against caol-gas outburst isprotective coal seam exploition. In connection with upper protective coal seam and theF14-15—22090working face mined of No.11mine,pingdingshan coal miningcorporation Ltd, it studies on the protective area and law of the gas migration. It isSignificance of coal mine production safety and further study of the protective layermining of coal and gas outburst prevention.The layer stress and the strain are simulated by use of the COMSOL Multiphysicssoftware. The contour lines and the change of direction、the displacement isolines andthe change of direction are simulated. According to the theory of gas migration and byuse of the COMSOL Multiphysics software, the law of gas migration are studied.Based on the field test, it studyes on the protective area and the change of gasparameters of protected seam.①The gas parameteres of the coal seam protected aretested by two groups of borehole arranged respectively from the trend and tendency thatare59.5°and73.7°.②The attenuation coefficient is Calculated that is0.0235⁰.0026d^-1.③The pumping ability about protected is Improved after protectivecoal seam exploition. The permeability coefficient is calculated by use of gas flow, andit is18¹71times what it is before protective coal seam exploition.④We test thedrainage radius of the protected layer that is5times bigger than that before protectivecoal seam mined.The above studies have shown that the protected seam has been relief, theprotective seam mined, and gas has been released to eliminate coal and gas outburst.