Managing Geologic Uncertainty in Pit Shell Optimization Using a Heuristic Algorithm and Stochastic Dominance
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Optimizing final pit limits for stochastic models provides access to geologic and economic uncertainty in the pit optimization stages of a mining project. This paper presents an approach for optimizing final pit limits for a highly variable and geologically complex gold deposit. A heuristic pit optimizer is used to manage the effect of geological uncertainty in the resources within a pit shell with multiple uncertainty rated solutions. The uncertainty rated pit shells follow the mean-variance criterion to approximate the efficient frontier for final pit limits. Stochastic dominance rules are then used in a risk management framework to further eliminate sub-optimal solutions along the efficient frontier. This results in a smaller set of final pit shells that could be further analyzed for production scheduling. Additionally, the original solutions are analyzed for changes in the mining limits and two regions are targeted as potential regions for further exploration.
KeywordsPit optimization Geologic uncertainty Risk management Heuristic optimizer
We would like to thank SRK Consulting and Golden Star Resource Ltd. for providing data and support for this study. We would also like to thank Ryan Martin for the input he provided on the stochastic models used in this study.
This project was funded through the ENGAGE grant from the National Sciences and Engineering Research Council of Canada.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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