GHD | Oceana Gold (New Zealand) Ltd | 12552081 | Waihi North 64 The predicted extent of the unsaturated zone within the andesite from the centre of the vein system is presented in Table G.22. The predicted change in Ohinemuri River flow in the Gladstone vein dewatering scenario is presented in Table G.23. The predicted rate of groundwater inflow per 1 m section of the vein is 1.25 x 10-4 m3/sec (10.8 m3/day). Table G.22 Predicted extent of unsaturated andesite from the centre of the Gladstone vein system (modelled at distance 471 m) Orientation from Gladstone Vein system Predicted extent of unsaturated andesite within deep groundwater system (m)* Northwest 83 (with additional unsaturated area between 183 – 202) Southeast 228 * Where pore water pressure is less than zero Table G.23 Predicted change in Ohinemuri River flow compared to current conditions in Gladstone vein dewatering scenario Location Predicted change in Ohinemuri River flow (m3/day) Ohinemuri River -1.5 G.2.3 Surface water catchment assessment results The current and predicted surface water catchment areas during all assessment scenarios for TB5, OH3 and OH6 are presented in Table G.24. The current and predicted surface water catchment areas during each assessment phase for TB4 are presented in Table G.25. Table G.24 Results of GOP excavation and development as a TSF impact on surface water catchment areas for TB5, OH6 and OH3 Surface water catchment Surface water catchment area (ha) Percentage reduction from current conditions Current conditions All GOP excavation and TSF scenarios Ohinemuri Tributary (TB5) 48.8 41.0 16% Ohinemuri River west of Gladstone (OH6) 5.9 4.7 20% Ohinemuri River east of Gladstone (OH3) 24.4 19.5 20% Table G.25 Results of GOP excavation and development as a TSF impact on surface water catchment areas for TB4 Surface water catchment TB4 Surface water catchment area (ha) Percentage change from current conditions Current scenario 18.6 - GOP Excavation / Operational TSF 13.8 -26% TSF Closure / Long-term TSF 32.5 +74%
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