Methodology of the Mineral Resource Classification

Abstract

The quantitative classification techniques are based on geostatistically quantified uncertainties in the estimated resource and reserve values. This should include estimation of the uncertainties in grade, volume (which is largely controlled by the geological interpretation and constraints), samples quality and tonnage factor. The quantitative classification methods were traditionally focused on the grades estimation uncertainties which are discussed in this chapter. The most commonly used methods include estimation variance approximately estimated using auxiliary geostatistical functions (e.g. F-function) and empirically estimated resource uncertainties, obtained using conditional simulation methods. The most efficient way of using the estimation errors for classification resources is by relating them to the production rates, including the annual, quarterly and monthly productions.

These methods allow to quantify the quality of the estimate but doesn’t address issues such as the data quality and robustness of the underlying geological model. If there are any significant uncertainties in either of these two items then the final classification should reflect this.