Study on Application of Double Pre-split Drilling Hole Blasting in Coal Seam with High Content of Gas and Low Permeability

This paper takes No.6 coal seam with high content of gas and low permeability in 601-3 working face of Lvtang Coal Mine as the research object, the double pre-split blasting technology was applied to the coal seam with high content of gas and low permeability, the double pre-split blasting mechanism was studied, numerical simulation was used to study the law of crack growth under different pre-split spacing conditions, and the influence of double pre-split blasting on single-hole gas flow, single-hole gas concentration and permeability coefficient of coal seam was investigated. The research results show that, compared to before blasting, the average pure flow of single-hole gas increases by 3.25 times, the concentration of single-hole gas increases by 2.28 times, and the permeability coefficient of coal seam increases by 2.15 times on average in double pre-split blasting zone. The amount of gas extraction is effectively increased, the production speed of working face is accelerated, and the safe production of mine excavation is guaranteed.