Parameters Optimization of High Level Boreholes Drainage Technology in High Outburst Thick Coal Seam

In order to accurately analyze the effect of high level boreholes,based on high level boreholes gas drainage theory,an orifice meter and a measured-gas bore are installed in each borehole of working face high level drill field.The gas flow and concentration in each borehole pipeline are measured according to the drilled footage,and the gas mixed flow and the gas scalars of the borehole are achieved by calculating.By analyzing and optimizing various parameters of drainage borehole,the layout of efficient and reasonable high level drainage borehole is obtained.