Optimized Open Pit Mine Design, Pushbacks and the Gap Problem-A Review
C. MEAGHER1, R. DIMITRAKOPOULOS1, D. AVIS2
1COSMO - McGill University, 3450 University Street, Montreal, Quebec, H3A 2T5, Canada
2McGill University, 3480 University Street, Montreal, Quebec, H3A 2A7, Canada
Keywords: pushback design, open pit optimization, cardinality constrained graph closure
Abstract
Existing methods of pushback (phase) design are reviewed in the context of “gap” problems, a term used to describe inconsistent sizes between successive pushbacks. Such gap problems lead to suboptimal open pit mining designs in terms of maximizing net present value. Methods such as the Lerchs-Grossman algorithm, network flow techniques, the fundamental tree algorithm, and Seymour’s parameterized pit algorithm are examined to see how they can be used to produce pushback designs and how they address gap issues. Areas of current and future research on producing pushbacks with a constrainedsize to help eliminate gap problems are discussed. A framework for incorporatingdiscounting at the time of pushback design is proposed, which can lead to minedesigns with increased NPV.
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