**12.3 Method of study**

The geophysical investigation involved electrical resistivity method (Dipole-Dipole Technique) and Very Low Frequency-Electromagnetic Method, the steps includes geologic mapping (reconnaissance survey of the study area) and establishing of traverses, production of geophysical location maps from the base/topographical map, data acquisition for all the geophysical methods followed by processing and interpretation. Inverted 2D Model of VLF data was generated using K-H Filter (Karous-Hjelt Filtering software). The Dipole-Dipole array was used for the data acquisition. The inter-electrode spacing (a) of 5 m was adopted while inter-dipole

separation factor (n) was varied from 1–5. The apparent resistivity values were calculated using π*n*(*n* + 1)(*n* + 2)*a* as the geometric factor. 2-D inversion modelling of the Dipole-Dipole data was carried out using DIPROTM Software developed by the Korea Institute of Geoscience and Mineral Resources
