Experimental study on rock cross-cut coal uncovering with ultra-high pressure hydraulic slotting

In view of the coal seam with low permeability, high gas content, high gas pressure and high outburst risk, the rock cross-cut coal uncovering is carried out, and the Xinji No.1 Coal Mine in Anhui Province is selected as the engineering background. The experimental study on the rock cross-cut coal uncovering by the ultra-high pressure hydraulic slotted crosscut is carried out, and the amount of slag discharged by the hydraulic slotting and the initial velocity of gas emission are investigated. The results show that after the ultra-high pressure hydraulic slotting measures are adopted, the equivalent radius of the uncovering area of the crosscut of coal seam group is increased by 31.9 times, the average initial velocity of gas emission is increased by 3.5 times, the amount of drilling work is reduced by 47%, and the coal is discharged by the slotting. The chip rate is more than 3 parts per thousand and the coal uncovering time is shortened by 50%. Based on this, the paper tests the effect of the measures in the area of rock cross-cut coal uncovering. The maximum residual gas content is 4.4m(3)/t, and the maximum residual gas pressure is 0.16MPa. The practice shows that the hydraulic slotting measures can greatly reduce the residual gas pressure (content) of the coal seam. Therefore, the ultra-high pressure hydraulic slotting technology can be used as an effective means for rock cross-cut coal uncovering in high gas and low permeability coal seam, and it can provide important reference and reference for similar conditions.