Direct volume estimation — a geostatistical technique for mine planning and grade control

Abstract

Direct volume estimation is a geostatistical technique for grade estimation of irregular volumes that has primary application to mine planning and grade control. It allows direct estimation of grade for realistic, practical mining and geological shapes and eliminates many of the approximations and deficiencies of conventional block representation of irregular volumes. In contrast to conventional block estimation, direct volume estimation provides grade estimates for irregular volumes and intersections of volumes that are geostatistically accurate as well as geostatistically complete. That is, estimates are obtained directly for irregular 3D shapes and include a measure of the estimation uncertainty that relates directly to the estimation volume. The latter provides a logical basis for risk assessment in a mine planning context. Elimination of the requirement for conventional block estimation also improves the efficiency of computer applications for grade control since accurate grade estimates can be computed for mining units directly from production sampling. This paper presents the background, theory, implementation and benefits of direct volume estimation in the context of mine planning and grade control.