Study on Seam Permeability-increased Effects and Pressure-relaxed Range During Protective Seam Mining

With the study on the deformation failure features of the seam under the condition of the mining in a protective seam, the boundary of the mining influen ce scope in the protective seam was determined.The RFPA2D-flow numerical simulation software was applied to the study on the stress distribution features of the prot ective seam, the variation law of the seam permeability and the seam deformation law.And an experiment study on the mining in the protective seam was conducted in t he horizontal seam of Pansan Mine.The results showed that after the mining in the protective seam conducted, the min deformation rate of the coal within the transition al pressure released zone was increased to 1.85% and the permeability coefficient of the seam was increased by 70 times.The gas drainage could make the effective pr otected pressure released angle in the strike direction and inclined direction of the seam expand from the original acute angle to 90° right angle and the pressure-relaxe d range of protected seam could be expanded.