Mechanism And Control Of Coal Bumps During Multiple Coal Seams Mining In Datong Coal Mine

The study on the machanism of coal bumps during extraction of multiple coal seams in Datong coal mine area is an important issue on safe mining and disaster prevention. Based on the field survey on the bump accidents of Meiyukou coal mine, Tongjialiang coal mine and Xinzhouyao coal mine in Datong coal mine, the control theory and techniques of coal bumps during extraction multiple seam mining with theoretic analysis, numerical simulation research and laboratory tests were conducted. This paper systematically analysed the remarkable characteristics of coal bumps in Datong coal mine area as well. It is showed that the coal bump probability during the lower seam mining was larger than that of the higher seam mining. Meanwhile, the coal bump probability and seriousness of the side which was close to the goaf were higher than those of the side close to the coal mass. It is revealed that the coal bumps were regional and had continuity. The indicators of coal bump proneness of coal-rock were given through laboratory tests and bump proneness identification. Based on the results, the new method with the index of releasing speed of remaining energy to judge the bump proneness of was proposed. At the same time, the measurement results of in-situ stress in Xinzhouyao coal mine showed that maximum principle stress was the horizontal stress and the horizontal stress was higher than the vertical stress. Based on the geological production conditions and the in-situ stress measurement results, FLAC3D (Fast Lagrangian Analysis of Continua in3Dimensions) was employed to numerically simulate the mining of the11th coal seam in Xinzhouyao coal mine with different mining sequences and different thicknesses of the interlayer between the9th coal seam and the11th coal seam. The occurrence mechanism of coal bumps were analysed in the numerical simulation. To prevent the coal bumps induced by mining in Xinzhouyao coal mine, pressure releasing through breaking the roof were conduced in workface. Meanwhile, pressure releasing blasting technolgy was implemented and evaluated.