Research progress on pressure released gas drainage technology of miningcracking zone in overburden strata of coal mine in China

The pressure released gas drainage of the mining racking zone was the main gas prevention method of the coal mining face. The paper introduced the research status on the dynamic evolution law of the mining cracking and analyzed the pressure released gas drainage principle. According to the different direct channels of gas drainage, the paper summarized and provided the gas drainage classification method of the mining cracking zone. Based on the gas absolute emission volume from the coal mining face, a classification selection method of the mining cracking zone gas drainage technology was provided. The paper had an analysis statement on the advantage and disadvantage as well as the layout method of gas drainage method in different mining cracking zone, provided the certain design method and the technical parameters and explained the effect of different drainage method with the site cases. Finally,with the summarization and conclusion on the research status of the gas drainage technology in the mining cracking zone, the paper pointed out that the 3D evolution model of the mining cracking zone, accuracy technical parameters of the high efficient gas drainage and the intelligent gas drainage technology and equipment would be the future research focus and development tendency of the gas drainage from the mining cracking zone of the overburden strata.