Research on the causal mechanism of a rock-burst accident in a longwall roadway and its prevention measures

Abstract

Based on the characteristics of the disaster and the geo-conditions at the scene, this study analyzed the occurrence mechanism of a serious rock-burst accident occurred in Tangshan Coal Mine, China. Ground stress measurement shows that the mine is in high ground stress area dominated by horizontal tectonic stress. Laboratory testing showed that the coal was a hard seam over-bedded by a thick and hard roof stratum. The calculation results showed that the accident occurred in the roof rebounding area. It is proposed that the hard roof and the hard coal seam formed a seesaw structure around the working face. The vertical pressure relief caused the rib coal mass losing its clamping forces from the roof and floor, rushing into the roadway, resulting in rock-burst accident. Based on the causality mechanism of the rock-burst disaster developed in this study, pertinent coal bump prevention measures have been undertaken in practice. Large-diameter boreholes were drilled to eliminate the pivot effect of the seam. Roof blasting was undertaken preventing the roof from forming a seesaw plank. This study developed a new causality mechanism of rock burst for coal mines with hard roof and hard seam geo-conditions.