Research and Application of Electromagnetic Wave Multi-frequency Synchronous CT Detection Technology in Gas Enrichment Area of Coal Mine

In order to detect gas enrichment area quickly and effectively, a forward model of gas enrichment area was established based on radio wave perspective and joint iterative tomography. Electromagnetic wave CT detection was carried out at 0.3 MHz, 0.5 MHz and 1.5 MHz at the same time. Changes in the receiving field intensity value, absorption coefficient and relative attenuation coefficient were analyzed through the comprehensive curve and relative attenuation coefficient contour map, and multi-frequency synchronous CT detection test was carried out in 28118 working face in Malan Coal Mine. The results show that compared with the normal coal seam, from low frequency to high frequency, the receiving field intensity value in gas enrichment area is getting smaller and smaller, the absorption coefficient and the relative attenuation coefficient are getting larger and larger; the measured field intensity value and the relative attenuation coefficient have obvious intersection points in the comprehensive curve, and there is an obvious strong attenuation area in the result map of the relative attenuation coefficient, high frequency has high resolution for anomalies. Electromagnetic multi-frequency synchronous CT detection technology can identify gas enrichment abnormal areas in mining working face.