Fine comprehensive exploration technology for goafs in Shenfu mining area
In order to finely identify the previously-mined unknown small coal mine goafs in the Yiyuan Coal Mine of Shenfu mining area,and provide scientific basis for management of goafs,it was necessary to carry out comprehensive exploration using the technologies of transient electromagnetic method,drilling,and logging,etc.,to investigate the distribution range and water abundance of the goafs.The results show that the physical properties of the coal seam were stable,and the curve shape was obvious from the logging curve.The coal seam had the characteristics of high resistivity,low density,and low gamma,which was classified as a high resistivity layer(up to 1000 Ω·m)with poor conductivity;while other mudstone,sandy mudstone,sandstone,etc.,exhibited the relatively low resistivity;the physical properties of the coal seam and surrounding rock differed significantly.The transient electromagnetic method adopted a detection parameter combination of 280 m rectangular emission wire frame,emission frequency of 25 Hz,gain of 22~25,emission current of 8 A,and integration time of 15 s for clearly reflected to the known goafs and it was inferred that the total area of the room and pillar mined-out areas in the 3-1 coal seam was 0.985 km2;the 2-2 coal and 3-1 coal room and pillar goafs were exposed,verifying the geophysical inference of the 3-1 coal goafs through drilling.Logging,transient electromagnetic exploration,and drilling were applied comprehensively,achieving the goal of refined and comprehensive exploration.