Study On Mining Technology Of The Working Face In Pressure Relief Area Of Close Multiple Coal Seams

At present, we have gotten great achievements in study of mining technology ofsingle coal seam, but the results of research on the mining technology of the working facein pressure relief area of close coal seams is less, there are still many problems that deservein-depth studies.Based on the geological structure of close coal seams at Shaqu coal mine, the pressureobservation of No.25102working face shows that there are not first weighting and periodicweighting, the influence scope of the lead abutment pressure is30m, stress concentrationcoefficient is1.81; the average supporting resistance of support is2420kN, which is46.5%of the rated working end resistance, the utilization rate of support working resistanceremains to be improved. The law of stress distribution on the floor of section coal pillar ofNo.3+4coal seam researched by theoretical analysis and numerical simulation, it showsthat the area2.4m away from the edge of coal pillar is in pressure relief area, so No.25102working face and No.25301working face are both in pressure relief area. Thestrata-pressure behavior and moving law of overburden are studied by theoretical analysis;the failure depth in floor of the upper working face is determined to be4.63m, while theinterlayer distance is only5.5m, so it is influenced badly by mining of the upper coal seam.With No.25301working face advancing, caving zone of No.25301working face is5.5m ofrocks between two coal seams and11m of gangue of No.24301working face, total heightis16.5m, basic roof of No.24301working face is in fracture zone of No.25301workingface, gangue of No.24301working face is broken into blocks and can not be a structure, sothere are not first weighting and periodic weighting when mining. The stress anddisplacement distribution of the mining stope are studied by numerical simulation, thestrata-pressure behavior law is verified. The stability of surrounding rock of mining stopeof the working face in pressure relief area is studied, reasonable support schemes of faceand tailgate and advanced support technology of roadways are determined, and the initialmining measures are taken which can ensure the safety and efficiency of working face. Thefeasibility of mining technology of working face in pressure relief area is analyzed, and theresearch results and methods can be used as reference and guidance for mining under thesimilar conditions.