The application of vertical electrical sounding in geomechanical recognition of host rock mass of anomaly III of Narigan deposit, Bafgh region, Central Iran zone

The electrical method as a geophysical survey can show the geological parameters including fragmentation, rock mass alteration index, saturation percentage and groundwater quality. These parameters play an important role in rock mass engineering classification by affecting the rock mass quality design (RQD) and geological strength index (GSI), mineralization of elements and drilling method. In this paper, using the vertical electrical sounding method in subsurface layers, the determination of these parameters and subsequently two mentioned indicators in anomalous III pyroclastic rock masses of Narigan deposit was investigated. The results showed that the interpreted electrical resistivity (using IPI2win software) has an acceptable correlation betweem the degree of alteration index and GSI in the rock mass. However, accurate determination of GSI and RQD using this geophysical method is not very reliable. In other words, using a mathematical equation, it is not possible to estimate the amount of GSI and the alteration index with the electrical resistivity.