Mineral prospectivity analysis of the Wagga-Omeo Belt in NSW

Abstract

In preparation for a major geological mapping program within the mineral endowed Wagga-Omeo Belt in central-southern NSW, the Geological Survey of New South Wales, in conjunction with the Centre for Exploration Targeting at the University of Western Australia, is undertaking a mineral resources assessment of the region. The Wagga-Omeo Belt in NSW has been a significant tin, gold, silver and copper producer. This study has used predictive mineral endowment of the region by estimating the number of undiscovered deposits, estimating mineral endowment, and by predicting the likely locations of undiscovered deposits. Both spatial prediction (mineral prospectivity mapping -- MPM) and quantitative resource assessment (QRA) were undertaken for a study of tin mineralisation in the region. This study has focused on the use of total magnetic intensity, gravity, radiometric and digital elevation data, together with geological and metallogenic data. Where sufficient data existed, both internal data-driven analysis and external exemplar/analogue application were undertaken. It used local spatial analysis that incorporated the use of spatial models (e.g. Poisson, binomial) to directly predict deposit locations. To reconcile final estimates in some areas, Weights of Evidence (WofE), geographicially weighted regression (GWR) and neural networks were used. In areas of insufficient data, predictive estimation was knowledge driven and incorporated expert opinion, fuzzy and Boolean logic, fuzzy WofE and neuro-fuzzy operations. Using these processes/operations, we were able to better pin down positions where undiscovered deposits were likely to be found. Although this study has just begun, preliminary results indicate several areas requiring further assessment and field mapping follow-up