近距离煤层及上覆煤柱协同开采技术实践

Cooperative mining technology of near distance coal seam and overlying coal pillars

封闭煤层的开采会保留大量总宽度为30~40 m的断面煤柱,造成了煤炭资源的巨大浪费,并存在自燃、失稳和破坏剩余煤柱的风险。通过数值模拟,研究了下煤层巷道与上覆煤柱水平距离(即间距)对巷道围岩控制和合理布置的影响,分析了上覆煤柱宽度对采场地压和煤柱回采率影响的机理。东周窑煤业公司的实践表明,当水平间距由0 m增大到15 m时,巷道围岩变形量、围岩应力峰值、塑性区面积均显著减小;当上覆段煤柱宽度由25 m增加到40 m时,采场横向应力峰值和超前轴承应力峰值分别下降21 MPa和12 MPa,采场地压驱动强度显著降低,煤层间覆岩和煤柱回收率分别提高7.45%和4.29%。结合顶柱放煤方式,提出了优化的概念和实现方法。

Mining of close coal seams envisages reservation of a large number of section coal pillars with a total width ranging 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 significantly.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.