Abstract: The rationality of the length of hole sealing for the seam drainage borehole in the extraction of a greater influence on the quality,when the hole sealing length is bigger,does not favor the hole sealing section of the gas extraction,and hole sealing cost increases,whereas when the hole sealing length is small,without hole sealing part and the coal wall fracture conductivity,borehole leakage and affect the quality of borehole extraction.In order to determine a reasonable length of hole sealing,in view of the ditch coal mine 302 working face under the specific geological condition,the singlehole acoustic emission on the pressure relief area and the stress,high range are studied,through the analysis of unloading zone,the reasonable hole sealing length,and combining the test hole drainage borehole surrounding extraction data,verified analysis,it is concluded that the reasonable hole sealing depth of the working face is 8 m.

Key words: sealing hole length,fracture conduction,unloading area,stress concentration area