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Borehole Tomography and Surface 3D Radar for Coal Mine Subsidence Detection

Experimental cross-hole and surface-penetrating radar surveys were conducted along a section of highway that had collapsed into underground coal mine workings. The cross-hole radar method provided information about bedrock and overburden conditions at depths not attainable using surface radar, while the surface radar enabled a detailed analysis of the roadway conditions. Through coincident analyses of borehole tomograms and surface three-dimensional plots, additional locations along the highway where mine-related disruption has occurred, and where a relatively high potential for future collapse exists, were detected. The results of this study demonstrate the applicability of radar methods to mine-related subsidence problems, and show that a more complete characterization can be achieved by employing both borehole and surface radar methods.