Study On Recovery Technology Of Residual High Stage Coal Pillar In Steeply Inclined Thick Coal Seam

Under complicated geological conditions of the large scale of residual pillar threatens the safety of mine production,the residual security coal pillar recovery is facing severe challenges.Take Shenhua energy co.,LTD.JianGou coal mine + 495 level B3 + 6 high residual phase of coal pillars(120 m by 50 m by 108 m)in xinjiang province as the background,the numerical simulation,theoretical analysis and field monitoring were adopted,safe extraction of residual coal pillar and the blasting of the top-coal weakening were researched,the steep seam pillar residue stress evolution characteristics and blasting mechanism were revealed,A scheme to increase the rate to caving and drawing characteristics and soften top-coal with rationality were presented.The main achievements have been made:(1)Space for proven residual pillar size,the drilling method for detection of coal pillar and the drilling situation analysis,comprehensive residual pillar in +495 level B3+6 work face is 120 m x 50 m x 108 m(length x width height)(2)Under different recycling height based on FLAC3D numerical simulation,the residual internal stress migration characteristics of coal pillar,the analysis of residual pillar by coal bed mining disturbance internal stress was analyzed,The greater the internal stress concentration of the coal,the greater the internal stress in the coal body is at 50.0m,and the internal stress of the coal body exceeds its uniaxial compressive strength.the strain distribution law of evolution safe extraction is 43 m in height.The remaining 67m pillar has collapsed and is normally mined at the level of +469 below(3)Based on the theoretical analysis,the fracture circle radius of the coal blasting is obtained,and the numerical simulation of ANSYS is adopted to analyze the method of comparative analysis,and the optimal blasting interval of top coal risk is 4m.According to the numerical simulation,the vibration velocity,pressure and displacement of each monitoring unit are determined as 6m.(4)the coal block degree and crack development degree of the coal are tested by borehole TV and geological radar,and the coal can be released successfully.Of blasting area of the portable PASAST-M after detecting the danger zone,on the working plane under goaf danger relieving effect is remarkable,the detection results are three dangerous areas,according to the acoustic emission monitoring of large energy during the process of working face advancing micro-seismic events are greatly reduced,stress release in coal.Thesis research results in the design of recycling high stage coal pillar extraction scheme and blasting parameters and optimization has good scientific and practical value,provides a basis for the study of residual side pillar recovery guide.