f Detection Of Conductive Fracture Zones By Underground Multicomponent Dc-Resistivity Surveying

Underground multicomponent DC-resistivity can be used to locate<br>conductive zones in the vicinity of underground excavations.<br>The method was used at the Waste Isolation Pilot Plant in<br>southeast New Mexico to locate fluid saturated fracture zones<br>within the Salado evaporite formation. Two deep cased drill<br>holes north of the facility were used as a bipole current source.<br>A two-meter dipole was used to observe the three orthogonal<br>components of the potential difference along profiles in the<br>underground excavations. Fracture zones were located in several<br>areas and later verified by hydrological tests and subsequent drilling.<br>The method can.be readily adapted to other applications such as<br>road- and water-tunnel testing, and underground mining.