Supporting Technical Assessments

GHD | Oceana Gold (New Zealand) Ltd | 12552081 | Waihi North ii Table G.13 Predicted shallow groundwater table drawdown at the edge of the pit and drawdown zone of influence during GOP excavation (SEEP/W) 57 Table G.14 Predicted groundwater discharge from the pit area to surface water receiving environments under current conditions and after development of the TSF (SEEP/W) 60 Table G.15 Predicted change in shallow groundwater level at the edge of the pit compared to current conditions, and zone of influence, after development of the TSF (SEEP/W). 60 Table G.16 Predicted groundwater discharge to surface water bodies during operational TSF scenario 61 Table G.17 Predicted groundwater discharge to surface water bodies during TSF closure scenario 61 Table G.18 Predicted groundwater discharge to surface water bodies during long-term TSF scenario 61 Table G.19 Predicted flux to the deep groundwater system and TSF drainage system during operational TSF and TSF closure scenarios (SEEP/W) 62 Table G.20 Sensitivity analysis of TSF Closure model scenario – hydraulic conductivity of the geosynthetic liner (SEEP/W) 62 Table G.21 Sensitivity analysis of TSF Closure model scenario – TSF capping layer infiltration rate (SEEP/W) 62 Table G.22 Predicted extent of unsaturated andesite from the centre of the Gladstone vein system (modelled at distance 471 m) 64 Table G.23 Predicted change in Ohinemuri River flow compared to current conditions in Gladstone vein dewatering scenario 64 Table G.24 Results of GOP excavation and development as a TSF impact on surface water catchment areas for TB5, OH6 and OH3 64 Table G.25 Results of GOP excavation and development as a TSF impact on surface water catchment areas for TB4 64 Table G.26 Predicted receiving water quality in the long-term TSF scenario (values in mg/L) 65 Table H.1 NRS assessment – model scenario summary 70 Table H.2 NRS model set-up 73 Table H.3 NRS model adopted hydrogeological material parameters 73 Table H.4 NRS groundwater inflow rates and distance of influence of dewatering for uphill diversion drain construction 74 Table H.5 Predicted leachate capture and leachate seepage through zone A liner 74 Table H.6 Predicted groundwater and leachate captured in sub-soil drains 74 Table H.7 Predicted leachate flow to Ohinemuri River within groundwater 75 Table H.8 Predicted receiving water quality in the NRS closure scenario (values in mg/L) 75 Table H.9 Sensitivity analysis for NRS Closure scenario 77 Table I.1 TSF3 base model set-up 85 Table I.2 TSF3 base model adopted material parameters 86 Table I.3 Calibrated horizontal gradient across the TSF3 site 86 Table I.4 Calibrated stream baseflow 87 Table I.5 Calibrated groundwater levels and well pair vertical gradients 87 Table I.6 Summary of steady state model scenarios for Cross-section 1 (all stages of TSF3 construction) 89 Table I.7 Summary of transient model scenarios for Cross-section 1 (construction dewatering) 90 Table I.8 Boundary conditions for TSF3 model scenarios (where different from Table I.1) 90 Table I.9 Adopted material parameters for TSF3 model scenarios (where additional to Table I.2) 91

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