Eliminating Outburst Scope and Effect Evaluation of Protective Layer Mining Under the Influence of Coal Pillar

Taking the protective layer mining of a mine as an example, according to the coal seam position relation and roadway arrangement between the protective layer C₅,C₁₂ and the protected layer C₈, it put forward two indicators of the residual gas content and drilling index K₁ value to investigate the protection scope. Based on three aspects of maximum vertical protective distance, towards and inclination, it analyzed the protection scope, and concluded that the relief angle of towards was 60 °; C₅ on the C₈ tilt up and down pressure relief angle was 70 ° and 77 ° respectively, C₁₂ on the C₈ tilt up and down pressure relief angle was 69 ° and 90 ° respectively. By using the FLAC^3D software to simulate No.2 and No.12 uphill pillar influence scope in the C₁₂ coal seam, the simulation showed that the coal pillar impact had expanded field effect. According to the pressure relief angle, it determined the coal pillar extending bounded region. On this basis, it divided the region for 1801 and 1802 working face. At the same time, it took effective eliminating outburst and effect inspection measures, the gas discharge rate was more than 30% in this region, the prediction index and the effect test index were not overrun, eventually achieved safety mining in this region.