Study on the eliminating outburst technology and effect with increasing permeability and forced gas drainage by drilling hole cross the seam in outburst seam

摘要

To the question of the difficult gas extraction and the long elimination of the outburst low permeability coal seam, taking the specific gas geology conditions of 6-2 coal seam in a mine of huainan mining area for example, the theoretical analysis and engineering practice of the pressure grouting in the deep and shallow hole and the loose blasting in the medium-length hole are used. The grouting technology in the deep and shallow hole blocking off the fissures of the roadway and the deep and shallow drill sites, and it solves the question of the extraction from the roadway surrounding rock crack with high-pressure grouting of the drilling hole. The loose blasting in the medium-length hole makes the coal fracture sufficiently develop, and the fracture network resulting from blasting makes the degree of pressure relief of the coal in the test area increase significantly, and the coal seam permeability is effectively increased. The engineering practice results show that the borehole gas extraction concentration could be increased by 7.4~10.5 times by grouting in the deep and shallow hole, and the average extraction scalar quantity has increased 9.2 times after the loose blasting in the medium-length hole, and the time of drainage up to the standard is 85 d, it shortened four months than traditional method. The technology guarantees the normal alternate mining.