Quantitative Methods of Assessment of Undiscovered Uranium Resources: A Review

In 1992 IAEA published in TECDOC 344 a comprehensive review and an instruction manual of quantitative methods of mineral resource assessment. The TECDOC 344 presented material prepared between 1985 and 1989, which provides a comprehensive survey of statistical models and assessment methods useful in undertaking mineral potential assessment of uranium deposits. However, the focus of the 1992 review was on statistical framework at the expense of critical geological features of uranium deposits which underpin the robustness of mineral resource assessment. The 1992 review also not on GIS based techniques, as these had not been developed when the review was published. This was partially overcome by a new IAEA guidebook (IAEA, 1994), which focused on techniques of spatial data integration (including GIS) for mineral exploration and, resource assessment and environmental studies. The present review only briefly discusses methods described in the previous two publications but focuses predominantly on GIS-based methods/models of assessment. The main objective of the review is to describe methods of quantitative mineral resource assessment, but as most quantitative methods rely on delineating permissive or favorable tracts. It also provides a brief review of qualitative methods for delineating tracts with different levels of mineral potential (prospectivity or favorability). In its scope the review is not extensive but aims to produce a critical review of most common methods. The main purpose is to provide guidelines, which can assist in selecting method(s) suitable for specific regions and/or specific tasks. The review only includes a few case studies. This is principally because it is intended to be an introduction to a series of separate contributions dealing with case studies. References to important case studies are included in this review. The main focus of the review is to provide sufficient information to the end users so that they can select one or the other methods based on their specific needs and objectives. The principal features of a number of important methods are summarized in a table, the aim of which is to assist in the selection of the suitable method(s). The review also includes a number of important recommendations that could be useful for conducting systematic quantitative resource assessment of yet to be discovered uranium deposits. These include: (1) compiling and updating of descriptive models or uranium deposit style and making them compatible with a process based mineral-system approach; (2) compiling grade-tonnage models of deposits styles; (2) preparing deposit-density models of deposit styles; and (4) identifying mappable signatures associated with critical features of uranium deposits styles and mineral systems. (author)