Determination of Critical Gas Drainage Volume in Fully Mechanized Caving Face in Extra-thick Inflammable Coal Seam

Based on the double coupling influence of gas drainage and coal spontaneous combustion in the extra- thick coal seam,the critical gas drainage volume in the fully mechanized caving face was determined. According to the site measurement by the bundle tube monitoring system and the numerical simulation with Fluent software,it was obtained that the critical air quantity in the fully mechanized caving face was 1 100 m3/ min under the control conditions of coal spontaneous combustion and the critical gas drainage volume in the fully mechanized caving face under the coupling influence of the comprehensive gas drainage and the prevention and control of coal spontaneous combustion was 180 m3/ min.