Research On Coal Pillar Optimization And Surrounding Rock Control Technology In Huangling No.2 Mine

The coal seam in Huangling mining area of Shaanxi Province has superior occurrence conditions and mainly mines near horizontal thick coal seams.However,due to the large buried depth of the working face,there are many problems in the retention of coal pillars in the working face section.In this regard,taking 303 and 305 working faces of Huangling No.2 mine as the research background,the reserved size of coal pillar in 305 working face of Huangling No.2 mine is optimized and matched with roadway support parameters by means of theoretical calculation,field measurement,numerical simulation and field test.The main research results are as follows:(1)Through the method of theoretical calculation,the width of plastic zone of roadway side coal pillar,the width of plastic zone of goaf side coal pillar edge and the width of bilateral plastic zone in Huangling No.2 mining face are analyzed.Combined with the limit equilibrium theory,it is preliminarily determined that the reserved size of coal pillar in Huangling No.2 mining face is not less than 11.8M.(2)According to the field measurement results of roadway ground pressure distribution law in 303 working face,the analysis shows that the influence range of advance bearing pressure in 303 working face is about 55m;Under the condition of primary mining,the plastic zone width of section coal pillar is about 1m～3M.Under the condition of secondary mining,the plastic zone width of section coal pillar is about 3M～5m.The size of 16m section coal pillar can meet the requirements of mine safety production and has a certain optimization space.(3)According to the numerical simulation results of different coal pillar sizes,when the coal pillar size of 305 working face changes from 11m to 12M,the reduction of vertical stress in the coal pillar is the largest,and the horizontal displacement stability width within the coal pillar size of 12m section is up to 8m,which can ensure the safety and stability of the mining roadway.Therefore,it is determined that the coal pillar size of 305 working face is 12m.(4)Through supporting the roadway support parameters of 305 auxiliary haulage roadway and field observation at 305 auxiliary haulage roadway,the maximum subsidence of 305 auxiliary haulage roadway in the whole observation period is 103mm and the maximum displacement of two sides is 99mm,which can ensure the safety and stability of the roadway.Therefore,it can be considered that the reserved size of coal pillar in 12m section of 305 working face is reasonable.