wAbstract
@Three-part resource assessments, begun over 30 years ago, provide
a framework for making decisions concerning mineral resources
under conditions of uncertainty. The parts include general locations
of undiscovered deposits that are delineated from a deposit type's
geologic setting; frequency distributions of tonnages and grades
of well-explored deposits that serve as models of grades and tonnages
of undiscovered deposits, and number of undiscovered deposits
that are estimated probabilistically by type. Recently improved
deposit density models show how to make probabilistic estimates
of numbers of undiscovered deposits. Significant progress has
been made showing how to reduce uncertainty and risk by the practical
integration of the fundamental kinds of information needed by
decision-makers. The approach is founded on internally consistent
mineral deposit models that help convert the output of assessments
into forms helpful to decision-makers. This integration of models
and methods is a source of strength that reduces the chances of
biased estimates, but it is also a burden, requiring careful development
of models and applications of methods. Before decisions are made
on where to explore, decisions must be made about what to explore
for and whether it is worth the risk.
Keywords: Models; Densities; Scales; Uncertainty; Riskx
1. Introduction
2. Short history of three-part assessments
3. Linked deposit models
@3.1. Descriptive models
@3.2. Cost models
@3.3. Density models
@3.4. Grade and tonnage models
4. Delineation
5. Number of deposits
6. Integrating the parts
7. Summary
References