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To explain the phenomenon that the gas spurt which emerged after the coal bump, the variation before and after the coal bump including the microfractures in the coal and rock mass, the temperature, etc. were analyzed, also the influence of the mine seismic induced by the coal bump to gas adsorptive ability was analyzed, and gave the reasons why the phenomenon exists from multi-angle. The variation of the porosity and permeability of the coal under loading were researched by theoretical calculation and test of the gas permeability. Based on the constitutive equation of the gas coal, obtained the permeability curve of the coal under loading by using the relationship of stress-permeability under triaxial compression tests. The results show that the coal bump makes it possible for the gas to spurt, and the mechanical or non-mechanical effects given by the gas cause the descend of the strengthen but the ascent of the fragility of the coal and accelerate the deformation of the coal at the same time. The coal's triaxial compression tests show that its porosity and permeability have a tendency to reduce first and then to increase, and they will raise shapely when the stress is up to 70% of the failure load. The expand of the microfractures in the coal and rock mass and the increase of the permeability are the most direct causes for the numerous gas spurt after the coal bump in the coal mine with massive gas. The associated phenomenon with the coal bump like mine seismic and the temperature of the rock mass increasing stimulate the desorption and release of the gas. [ABSTRACT FROM AUTHOR]