Cooperative mining technology of near distance coal seam and overlying coal pillars
Mining of close coal seams envisages reservation of a large number of section coal pillars with a total width ran-ging from 30 to 40 m.This results in an enormous waste of coal resources and risks of spontaneous combustion,instability,and damage to the remaining coal pillars.Using the numerical simulation,the effect of horizontal distance between the lower coal seam roadway and the overlying coal pillar(i.e.,spacing)on the surrounding rock control and rational layout of the roadway is studied.The mechanism of effect of the overlying coal pillar width on the ground pressure of the stope and coal pillar recovery rate is clarified.The engineering case study shows that when the horizontal spacing was increased from 0～15 m,the surrounding rock deformation,surrounding rock stress peak value,and plastic zone area of the roadway decreased sig-nificantly.When the coal pillar width in the overlying section was increased from 25～40 m,the peak values of lateral and advance bearing stresses in the stope dropped by 21 MPa and 12 MPa,respectively.Besides,the ground pressure driving strength of the stope was significantly reduced,and the recovery rates of the overlying coal pillar and rock between the coal seams were increased by 7.45％and 4.29％,respectively.Combined with the top coal pillar caving pattern,optimization concepts and their realization methods were proposed.
万方数据
维普
