Analysis and optimizations on retreating mining measures of rock burst prevention on steeply dipping thick coal seam in deep exploitation

With the reduction of mine reserves in shallow coal-bearing series, the mining proportion of steeply dipping thick coal seam in deep strata is increasingly high. Deep exploitation not only increases the chance rock burst happening in mine, but also there are some difficulties for the stability of corollary equipments in working face in the process of full-seam mining of steeply dipping thick coal seam. 4# coal seam of Huafeng colliery is under the geological condition of steeply dipping thick coal seam in deep mining. In the process of retreating mining, rock burst and stability of equipments always restrict the mine's production. Through comprehensive analysis of 4# coal seam, including the places of rock burst happened, comprehensive management actions of rock burst and the relevant mining method and so on, found that adopted the exterior entry layout of dislocated strata gateway in the colliery is still inadequate to improve the problem of stability of equipments along coal seam floor. Besides, continuous mining to the east is too long, reduce the mining speed and mining of protective seam are not effective measures, even the occurrence reasons of rock burst. In response to these issues, further proposed the internal entry layout of dislocated strata gateway, through theoretical and experimental analysis, getting that the reform of tunnels arrangement not only improve the stability of mining equipment, but also change the present situation of rock burst of 4# coal seam fundamentally in Huafeng colliery. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of China Academy of Safety Science and Technology, China University of Mining and Technology(Beijing), McGill University and University of Wollongong.