Abstract

This work provides a comprehensive application of a phenomenological model to simulate bacterial leaching of a three-dimensional heap of sulphide ores at a realistic scale. This tool, coupled with an optimization model, simulates different irrigation scenarios to help decision makers to optimize the operation of a heap by maximizing the economic returns. This phenomenological model is based on the Dumux research code for the core of calculations. It integrates different phenomena such as kinetic leaching, bacterial growth, oxygen transfer, unsaturated porous hydraulics, three-dimensional mass and energy transport, among other sub-models developed by different disciplines, providing a holistic and transdisciplinary perspective. The current model can represent both static and dynamic three-dimensional multi-lift heap leaching, predicting copper recovery and acid consumption comparable with existing literature data. In addition, our robust optimization tool can guide simulations and irrigation decisions towards improving heap-leaching operations. This is based on a strong mathematical structure that includes both operational and economic parameters, allowing for further functionality and continuous development. We tested the functionality of our integrated phenomenological model and optimization tool in a realistic 3-lifts bioleaching pile. For a set of adopted parameters, results show that copper recovery was more sensitive to model parameters related to bacterial behaviour than kinetic constants. Model parameters related to soil water retention curves and activation energies were of secondary importance. Results shows that our modelling approach provides a good representation of solution, heat and chemical fluxes along the heap, as well as effluents. On the other hand, the optimal irrigation plan generates considerably more Discounted Cash Flow (3.4% more DCF) compared to a base plan that irrigates the modules as soon as they are available (common operational criteria). Ongoing research is required to evaluate more complex scenarios, including other chemical systems such as chloride media.