STUDY ON CONTROL MECHANISM OF LOOSE COAL WORKING FACE SURROUNDING ROCK AND APPLICATION UNDER HIGH GAS COAL SEAMS

Most of coal mines in east China are high gas coal seams, so they are forced to adopt artillery mining. Taking the Xin zhuangzi coal mine as the engineering background, and using synthetical study methods, the fully-mechanized mining method was studied. The 66207 working face was arranged in the low stress zone for the mining of the above 66208 working face, by internal misaligned arrangement since mining design, thus, stress concentration caused by subsection coal pillar was avoided. Above the 7 coal seam 13m, it's like two meters thick, was cut by the technology of deep-hole presplit ting blasting using water gel explosive. The long-range and high tensile dynamic pressure impact was avoided for preventing the state transiting of key stratum. New hydraulic support and mining technology were designed, coal cutting and coal wall totally-enclosed in face guard with high pressure state. Based on the test result of 66207 working face, injecting water technique combination between long hole in the haulage roadway and tailgate in advance and shallow hole in the coal wall in advance was proposed. The working face was mining successfully with good safety and efficiency, realize the technological breakthrough of the three soft coal seam.