Complete Set of Technology of Hole Sealing and Concentration Increasing in Big Dip Broken Soft and Low Permeability Coal Seam

Abstract

The large dip and broken soft low permeability coal seam in Ewirgol Mining Area in Xinjiang has the problems of low pre-drained gas concentration and fast attenuation, and the extraction effect is not ideal. In order to solve this technical problem, a reasonable hole sealing parameter was determined based on the surrounding rock stress and crack zone distribution characteristics, according to the theory of pipe flow hydrodynamics, the equipment for testing the parameters of the drilling hole sealing was developed, and the testing and inspection of the sealing depth and sealing effect were realized. The radial expansion active pressure grouting sealing technology was proposed, and a new design was developed. The slurry expansion sealing material and process equipment have formed a complete set of high-efficiency sealing and concentration increasing technology equipment suitable for the occurrence conditions of large inclination multiple coal groups in Xinjiang. The results show that through the application test in Xinjiang Coking Coal No.2130 coal mine, the borehole sealing depth of the tested drilling should exceed 12 m, the grouting pressure of the borehole sealing of the test borehole reached 1.5 MPa, and the single-hole gas drainage concentration increased by 96% more than 96%, the extraction effect has been greatly improved.

Keywords

• large angle coal seam
• soft and low permeability
• sealing and concentration increasing
• gas drainage
• extraction effect