The Technology Research Of Gas Pre-drainage Through Cut Hole Drilling In Li Zuizi Coal Mine

Study on the cutting hole drilling technology of gas pre-drainage is aimed at the bad permeability in Li Zuizi mine Al coal seam and difficult issues such as gas drainage in Huainan mining group. Taking Li Zuizi mine Al coal seam as test object. Firstly analyzed the basic law of gas in coal bed, the flow in the basic parameters of gas in the coal seam, and gas in coal seams in the flow state. And then, basic parameters of Li Zuizi coal mine Al coal seam gas were measured at the test site, the original coal seam gas pressure maximum is1.995Mpa, the original gas content is6.753m3/t, the permeability coefficient is0.055963m2/MPa2.d, the gas flow attenuation coefficient0.0357d-1. The drilling drainage influence scope were tested during the cutting hole reaming in the use of reducing gas pressure at the scene,The drainage radius of influence by cutting hole from the3.81m to cut point of4.32m, according to the pump to optimize the layout of borehole radius obtained: Al coal seam drilling layout optimization by4mx4m for6m×6m grid, thus reducing the construction amount of drilling, but also improves the efficiency of gas drainage. Finally Li Zuizi mine Al coal seam cutting hole drilling results of gas pre-drainage was investigated to verify, the residual gas pressure in coal seam and the residual gas content were measured, the results:the residual gaspressure is0.54MPa, the residual gas content is1.35m3/t, and lower than the "critical value of coal and gas outburst prevention" in the regulations, this proves that the cutting hole drilling gas pre-drainage is useful to ensure the safe and efficient production of the mine, and provides guarantee for the late stage of the coal roadway driving.