Fault Detection Using Electrical Resistivity Tomography

Electrical Resistivity Tomography (ERT) data were acquired on the ground surface across an underground limestone mine access tunnel in an effort to characterize the roof rock. This investigation was conducted because simultaneous localized failure occurred on the ceiling of the access tunnel and elsewhere in the mine along a previously unknown northwest trending lineament. The interpretation of the ERT data indicates the limestone roof rock above the tunnel is dissected by several prominent clay-bearing near-vertical solution-widened fractures (joints or faults) that are not visually exposed on the ceiling of the tunnel. Roof rock failure in the mine access tunnel occurred at the intersection of projected lineament and one of the more prominent interpreted solution-widened fractures.