Experimental results from the CSM Tunnel Detection Facility using EM line current scattering (ELCS)

A series of field tests was performed at the Colorado School of Mines (CSM) Tunnel Detection Facility in late June 1989. The purpose of the tests was to establish the possibility of tunnel detection in the very heterogeneous environment of the CMS facility. The two methods considered were downhole CSAMT in the ELCS mode and in a cross-borehole configuration. The CSAMT frequency-domain signal was at 128 Hz or 1025 Hz. The odd harmonics (up to the ninth) allowed coverage of about 100 to 9000 Hz. Phase data relative to the transmitter were obtained for all measurements. The typical drift between the receiver and the transmitter was approximately 0.5 mrad/day.<>