Tomography of transmission in-seam wave attenuation coefficient and detection of collapse columns

In order to precisely detect collapse columns in coal mining face,and overcome the weakness in resolution of radio tunnel tomography,the authors studied t he technology of transmission in-seam wave attenuation tomography. Taking advantage of the new type of selfrecording mine seismograph,the number of geophones was u nlimited and the density of rays between shot and geophones was increased. Based on this equipment,this paper discussed the ART algorithm with a smoothness constraint to achieve tomography of transmission inseam wave attenuation. The new equipment and method was applied in the detection of collapse columns lay in the No. 3204 Coal Mining Face of Wangpo Coal Mine. The result shows that attenuations of transmission in-seam waves are sensitive to collapse columns. The result of tomography can disti nctly reflect the positions and boundaries of collapse columns in coal seam. It provides the basis to accurately determinate properties of collapse columns.