A Scheme of Computer-Based Mineral Deposit Modelling and Resource Evaluation of Precambrian Terrains

A significant part of Precambrian metallogenic provinces in India is covered by soil, sand, alluvium or weathered material, where the likely occurrences of concealed ore deposits do not show any surface signature of mineralisation. In fact, continuous exposures of fresh in situ rock are generally very difficult to find in such areas. Even if such exposures are found, these do not normally show any surface indication of mineralisation that was not known earlier. Under such circumstances, indirect non-conventional methods of exploration with the help of computer-based multivariate statistical analyses may provide modelling techniques by establishing the characteristic inter-relationships of geological, geophysical and geochemical parameters to enable prediction of new exploration targets at low cost. This paper focuses attention on the development of such computer-based statistical models and their utility in various stages of exploration in Precambrian terrains. The different stages of mineral exploration include (i) mineral belt modelling in reconnaissance stage, (ii) deposit modelling in regional exploration stage, and (iii) ore-body modelling in detailed exploration stage. An attempt has been made in this paper to present a holistic scheme of such modelling. Finally, the use of geostatistics with quantitative parameters of regional and detailed exploration stages has been suggested for computer-aided resource evaluation of different deposits and ore bodies in a metallogenic province. This is possible through the use of Geographic Information System (GIS) integrating different input data layers to generate various thematic maps of different mineralised belts and to produce a detailed project report for resource assessment.