Study on evaluation method of rock burst danger in Urumqi Mining Area

In order to evaluate the rock burst danger of the steep inclined ultra thick seam in Urumqi Mining Area, based on the previous studies, the comprehensive index method was applied to the re-division of the each factor, which could be suitable to apply to the steep inclined seam. The analytic hierarchy process was applied to determine the weight of each factor. The main conclusions were as the followings. ① The physical and mechanical properties of the steep inclined coal and rock mass and the structure features of the steep inclined seam structure could make the soft seam clamped between the hard roof and floor and could be easy to store great elastic energy under the horizontal structure stress and the gravity stress. ② The thrust fault and fold structure of the geological condition around the mining area would be the root cause of the shallow rock burst in Urumqi Mining Area. ③ In combination with the rock burst behavior features in Urumqi Mining Area, the stress difference coefficient was introduced to adjust the “mining depth”, the dimension radius of the dynamic system was induced to adjust the distance of the hard rock to the seam” and the analysis on the locations of the microseismic accidents occurred in the recent years was applied to adjust “the thickness of the hard rock”. The analysis on the microseismic accidents and the horizontal structure stress of each mine in Urumqi Mining Area was applied to add “a distance of the strike reverse zone in the Badaowan syncline seam” and the numerical simulation was applied to analyze the distance-stress relationship between the residual coal pillar and coal miming face to add “the horizontal distance of the residual coal pillars in the overburden strata”.Five geological factor indexes within the comprehensive index evaluation method were revised and the evaluation model of the rock burst danger in the steep inclined ultra thick