808 4.2.4 Inventory Dataset Selection Consumable material flows are linked to generic life cycle inventory datasets to enable impact assessment. Global-average datasets (GLO) are selected for key materials such as steel and rubber to provide a neutral and transferable reference. Table 1 shows the datasets selected for the example. Table 1: Dataset selected Parameter Dataset ecoinvent 3.12 Impact Assessment IPCC 2021-GWP100 Electricity market for electricity, medium voltage (GLO) 0.68 Grinding media/liners market for steel, low-alloyed (GLO) 2.03 Rubber market for synthetic rubber (GLO) 3.18 The use of global datasets reflects the illustrative nature of the case example. Emission intensities associated with material production and electricity generation vary by geography and technology. The values applied should therefore be interpreted as representative inputs for methodological demonstration rather than site-specific results. 4.3 Modelling and Scenario Simulation – Life Cycle Impact Assessment Process modelling and simulation scenarios provide the basis for extending optimisation results to carbon-based indicators. The discussion is organised in two parts: key outputs from a process optimisation perspective, followed by calculation and analysis of life cycle impacts. 4.3.1 Process Optimisation Results: Energy Performance Twelve operating scenarios were simulated, covering throughputs from approximately 87 to 101 tph. Corresponding mill power draw ranges from 1,716 to 2,078 kW, resulting in specific energy values between 18.6 and 21.7 kWh/t. The Operating Work Index varies between 20.6 and 24.0 kWh/t across cases. These results reflect typical optimisation trade-offs between throughput and energy efficiency and are consistent with conventional performance indicators used in comminution circuit optimisation. Under an electricity-only perspective, higher-throughput scenarios combined with lower specific energy indicate potential improvement relative to the base case (Table 2). Table 2 – Energy results from simulation across selected scenarios Scenario Throughput (tph) Specific Energy (kWh/t) Base Case 86.6 19.60 Sim 1 92.4 18.83 Sim 5 96.6 18.36 Sim 7 101.0 20.08 Sim 8 101.0 20.57 4.3.2 Life Cycle Impact Results: Electricity and Consumables Life cycle carbon impacts were calculated by combining scenario-specific outputs from the process optimisation model with the shared inventory defined in Section 4.2. Electricity-related emissions were derived from simulated specific energy values, while consumable-related emissions were calculated from mass-based consumable intensities linked to cradle-to-gate emission factors. Results are expressed as kg CO₂e per tonne of ore processed.
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