Study on microseismic activity law during change of anti-rockburst coal pillar width

In order to study the temporal and spatial activity law of microseismic events in the initial stage of coal pillar transformation transition in Hujlte Mining Ar ea,taking the original 35 m coal pillar to 120 m anti scour coal pillar in No.3102 working face of menkeqing coal mine as the background,the anti-rockburst effectiveness of 120 m coal pillar is determined, and the comprehensive prevention and control measures of rock burst during the transition period are proposed. The results show tha t: under the influence of the width change of hard roof and coal pillar,large energy microseismic events occur frequently during the transition period of coal pillar width,b ut the bearing effect of 120 m anti-rockburst coal pillar on the roof can block the goaf of this working face and adjacent working face. The microseismic events in the tra nsition period of coal pillar width mainly concentrated in No.3102 working face and slightly shifted to the coal pillar area.lt is found that the distribution height of high-en ergy microseismic events( 2105 J) shows a downward trend from +650 m to +620 m,and the distribution height of high-energy microseismic events( 103~ 105 J) increa ses from+ 615 m to + 625 m,and the activity of medium low-level medium sandstone roof is intensified and the focal height is up The results show that the distribution h eight of low-energy microseismic events(