1635 2. METHODOLOGY 2.1 Mining Alternatives Considered Traditional mine evaluation methods are not typically designed to capture the combined effects of selective extraction, early upgrading, in-mine recovery, backfill interaction and changing material flows. To address this gap, Mining3 developed a techno-economic evaluation framework to compare conventional underground mining with hybrid IPM configurations incorporating ILR and IMR. The framework evaluated, at a high level, three pathways that were assessed individually and in combination to determine how IPM could affect stope selection, material routing, processing capacity utilisation and project value. The model considered the material flows from ore access and stope development (with and without ore sorting), through to surface processing, as well as backfill and in-mine leaching. The three pathways explored were: ● In Conventional Mining (CM), stopes were created using Vertical Crater Retreat (VCR) methods. The extracted ore was hauled to surface and processed through standard comminution and flotation circuits. ● The addition of ILR allowed selected material to be upgraded underground near the point of extraction through sensing and sorting to reduce the volume transported to the surface and to increase the grade fed to the concentrator plant. ● IMR enabled the treatment of low-grade coarse material that would otherwise be uneconomical to mine using conventional methods and was also deployed on stopes backfilled with tailings. After initial stoping, these materials were placed into voids and treated in situ using controlled lixiviant circulation. 2.2 Model description A systematic, staged methodology was adopted to assess the viability of the underground mining project. This stepwise decision tree ensured that only technically feasible, economically viable and socially acceptable flowsheets progressed through the pipeline. Figure 4 shows the initial stages considered in the decision-making framework for the IPM assessment carried out in this study. Figure 4 –Stages 1 & 2 of the decision-making framework for the IPM assessment Stage 1: Deposit and stakeholder decision criteria characterisation focused on assessing the fundamental geological and geometallurgical attributes of the ore body alongside the environmental, social, governance and regulatory (ESGR) feasibility of the deposit. Stage 2: Financial modelling for the desktop study involved conducting a preliminary economic screening using techno-financial models to evaluate the potential viability of the mining options.
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