Prediction of Uncertainty in Tabular Vein Deposit Resources


Mr Clayton V.Deutsch, Mr Dhaniel Antunes deCarvalho

The position, thickness, and grade of vein deposits all contribute to resource and reserve uncertainty. The traditional methodology of creating a solid model then estimating grade does not permit a complete assessment of resource uncertainty. Simulated grades within a fixed solid model also does not give a realistic assessment of uncertainty. A comprehensive modeling workflow is proposed for tabular vein deposit resource uncertainty assessment. Position is simulated relative to the plane of continuity. Thickness is simulated relative to position. Grade is simulated within the vein geometry following appropriate local coordinates. Practical details are presented. Intersections from drill holes that are not perpendicular to the plane of continuity are handled by a data imputation framework. Flexible facet and tetrahedra-based grids are demonstrated. Multiple realizations are used for resource calculation, engineering design and assessment of the value of information for possible additional drilling. A case study is shown with data from a hydrothermal vein gold deposit.