A general perspective on geophysical methods in mineral exploration

Geophysical methods are known to play an indispensable role in mineral exploration. Over the years, they have undergone a phenomenal improvement in the design and development of equipment, methods and precision of data acquisition, processing and interpretation. Every geophysical method is directly or implicitly related to one or other physical property contrasts of the subsurface rock(s) and the target to be explored. Due to the fact that each geophysical method is specifically more suitable for a particular type or nature of mineral deposit with limited depth of exploration, many a time single geophysical method seldom yields highly reliable/desired results. This may be attributed to several factors including the quality of data, various noise factors, geophysical field parameters, choice of interpretation tools and techniques and above all, the inherent limitations of the method itself. Therefore, success of any geophysical survey may be enhanced by combining two or more geophysical methods for a particular investigation followed by right choice of processing and interpretation tools. This approach is called integrated geophysical strategy which ensures greater accuracy and highly reliable results. It is to be emphasized that geophysical modeling provides a generalized non-unique solution in terms of geometry (shape and size etc.) of subsurface sources. The spatial location of subsurface sources and their depth of burial can also be accurately be estimated by mathematical tools. This chapter presents the salient features of various geophysical methods and their applications and few case studies.