Measurement of Gas Effective Drainage Radius in Single Special Thick Seam

The paper introduced the measurement method of effective drainage radius of gas drainage hole.Taking gas pressure p and drilling hole gas concentration η as investigation targets,the effective drainage radius of one diameter drilling hole in Tingnan coal mine was determined by using borehole test method.Through the spot examination and the analysis of measured data,finally,the effective drainage radius and drainage time of drainage hole in Tingnan coal mine No.4 coal seam were determined,which provided a basis for the rational layout of coal mine gas drainage drilling.