Global grade-and-tonnage modeling of uranium deposits

Abstract

This contribution presents models of grade and tonnage distribution of various uranium deposit types and sub-types. A p-value derived from the Kolmogorov-Smirnov test is used for evaluating the goodness-of-fit of the frequency-grade and frequency-tonnage distributions to the log-normal distribution. The results indicate that both frequency-grade and frequency tonnage distributions of most deposit types and sub-types conform to the log-normal distribution at the 95% confidence level. Models created by dividing deposits into sub-types show significant improvement in the goodness-of-fit. The t-tests reveal that the grade and tonnage distributions of sub-types of the sandstone-hosted type (namely, roll-front, tabular, basal channel and tectonic-lithologic sub-types) are significantly different from each other. Furthermore, country-wise models of the roll-front deposits in different countries do not necessarily correlate, which explains the lower goodness-of-fit for the global frequency grade and frequency-tonnage models for sandstone-hosted deposits. This implies that sandstone-hosted deposits may differ in their geological settings from country to country, thus requiring some reclassification. The same applies to basement-hosted and unconformity contact deposits in Canada and Australia.