Incorporating geological and equipment performance uncertainty while optimising short-term mine production schedules

Abstract

Short-term production scheduling in open pit mining consists of defining the extraction sequence and process allocation of mineralised material over time-scales of either months, weeks, or days. An effective short-term production schedule ensures compliance with the production targets and restrictions imposed by the long-term plan. The method proposed herein outlines a new approach to simultaneously optimise the short-term production sequence with the mobile equipment allocation plan while incorporating both material grade and equipment performance uncertainty. A new simulation methodology is introduced to generate more realistic equipment performance scenarios, as well as a new concept of including ramp positions in the formulation to efficiently facilitate minable extraction patterns. This short-term model is bench-marked against a conventional design at one of the largest copper mines in the world, and the results show improved production target compliance by delivering more consistent ore quantity and quality to each processing destination, and a physical extraction sequence that has a greater likelihood of being realised in the face of equipment performance and truck cycle time uncertainty.