Holistic optimization of open pit to underground joint production plan

Authors: Soto, H; Villa, D Download Paper

Cite As:
Soto, H & Villa, D 2024, 'Holistic optimization of open pit to underground joint production plan', in Daniel Johansson & Håkan Schunnesson (eds), MassMin 2024: Proceedings of the International Conference & Exhibition on Mass Mining, Luleå University of Technology, Luleå, pp. 1459-1476.



Abstract:
It is common for Open Pit operations to face challenges throughout their life-of-mine such as decreasing grades and increasing processing and mining costs. Usually once a certain production period has been reached, planner question whether to continue the surface operation or transition to underground operations that would allow them to maintain the production in a sustainable operational framework, particularly caving operations due to their low operationing costs and high productivity. Since the decision regarding the underground operation, like the optimal elevation for production level, is largely influenced by decisions made for the surface operation, as the definition of the final pit, if planners do not visualize the joint operation an optimal plan in these cases usually leads to sub-optimal scenarios. This paper proposes a new workflow that generates a holistic optimization for the production plan, in terms of maximizing the NPV (or any other financial KPI), for a mine deposit that begins as an Open Pit operation and then transitions to a Caving operation. Simulating multiple scenarios according to several parameters as production targets, variable mining cost expressed as “premium” in caving operations and the investment required for each scenario; planners have the possibility to explore many strategies and identify areas of optimum solutions in a reasonable time using the Hill of Value technique.