Assessment of granite resources from batholiths and dykes using 2d eri techniques - a case study in salem district tamilnadu

Electrical Resistivity Imaging technique is considered as one of the most important geophysical methods in mineral exploration to locate hidden mineral deposits or rock types that are conductive or resistive. Unlike conventional 1D, ERI not only takes vertical resistivity variation but also it takes into account horizontal variation in resistivity. ERI is an inexpensive method in comparison with the direct investigations such as exploratory drilling. In this research the ERI has been used to study the degree of weathering of granite and locate the fresh granite below the surface in order to know the depth of the fresh granite capable of producing blocks with desired size. The ERI investigation has been validated with the geological investigation in order to identify the suitable granite for commercial exploitation. The ERI investigation has revealed the factors such as the volume of the overburden, degree of occurrence of fractures with depth and the depth to fresh granite rock that affect the recovery of commercial granite. The information from ERI image provides a clear picture corresponding to the successful recovery of the granite blocks.