Quantifiable Mineral Resource Classification: A Logical Approach

In terms of the reporting codes Mineral Resource classification is a function of increasing confidence in the geoscientific information and the associated resource estimate. An overview of Mineral Resource classification approaches is given; the tendency in resource classification is to concentrate on the confidence associated with the grade estimate. Uncertainties linked to tonnage and metal estimates are rarely explicitly mentioned. As for the risk associated with the underlying geological model it is often, if at all, only considered on a global rather than a local basis. The objective is to present a quantifiable Mineral Resource classification guideline that recognises uncertainty in both geological and resource models, considers confidence in estimation of metal content for specified production periods and also takes into account both the correlation of blocks in the block model as well the change of support between an estimated block and the production period. This classification method builds on a previous publication (Dohm, 2003), where a technique for assessing the combined risk associated with both the geological and grade models was demonstrated. The final result is a succinctly classified mineral resource model, which is based on objective quantifiable classification rules that recognises the uncertainty related to subjective interpretations of the available information.