2650 Table 4 – Summary of copper case data collected during the LCI Scope Source Descriptio n of emission source Emission factor Consumption per plant unit (kW for electricity, g/t for reagents, g/kWh for wear) Value Unit *1 2 3 4 5 6 7 Sc. 1 N/A N/A - - - - - - - - - Sc. 2 Energy Electricity is used to drive equipment, e.g., mills. 0.563 kg CO2e / kWh 44 650 34 328 6 887 3 636 2 526 527 5 591 Sc. 3 Wear of mill components The SAG/ball mill liners wear at a certain rate. 3.375 kg CO2e / kg steel 86.4 136.1 0 24.64 0 0 0 The mill grinding media wear at a certain rate. 3.375 1 871 1 727 0 61.6 0 0 0 Sc. 3 Reagents in flotation/dewater ing Collector 3.014 kg CO2e / kg reagent 0 0 127.8 0 1.6 0 0 Frother 2.581 0 0 54.8 0 0.9 0 0 Activator 3.014 0 0 30.4 0 0 0 0 pH Regulator 1.248 0 0 5 708 0 193.8 0 0 Flocculant 3.999 0 0 0 0 0 0.6 74.5 *1 – Primary grinding; 2 – Secondary grinding; 3 – Rougher flotation; 4 – Regrinding; 5 – Cleaner flotation; 6 – Concentrate dewatering; 7 – Tails dewatering 4.3 Stage 3: Life cycle impact assessment (LCIA) EFs act as conversion values that translate a specific activity into the amount of emissions it produces. To estimate GHG emissions, the appropriate EF for a given source is multiplied by the level of activity, which yields the quantity of each GHG released from that source. This is done in accordance the NGER Account Factors (2025) [13] (Equation 1 – Section 3.3). This equation is applied to all emission sources (electricity users, wear materials, and reagents) across the applicable plant units, and the results are shown in Table 5.
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