Supporting Technical Assessments

GHD | Oceana Gold NZ Ltd | 12552081 | Geochemical Assessment Wharekirauponga Underground Mine (WAI-985-000-REP-LC-0013) 30 Table 4 Assumed Water Quality Dataset from Waihi Source Statistic Model Input pH (pH Units) Nickel Dissolved Selenium Dissolved Copper Dissolved Arsenic Dissolved Lead Dissolved Antimony Dissolved Aluminium Dissolved Mercury Dissolved Zinc Dissolved Sulphate Iron Dissolved Manganese Dissolved TSF1A Seepage Median RS Seepage 6.3 0.004 0.001 0.001 0.001 0.0001 0.0002 0.01 0.00008 0.02 194 0.04 0.56 TSF1A Seepage 95%ile1 RS Seepage 5.4 0.300 0.005 0.003 0.003 0.0004 0.0050 0.33 0.00054 0.19 2,400 19 48 Waihi Dewatering Median Infiltrating Ground 7.3 0.020 0.009 0.001 0.010 0.0002 0.0067 0.02 0.00008 0.32 1,550 27 9 Waihi Dewatering 95%ile1 Infiltrating Ground 6.7 0.079 0.009 0.011 0.036 0.0046 0.0107 0.05 0.00008 1.21 1,780 62 10 Collection Ponds Median RS Runoff (Development) 7.2 0.100 0.001 0.001 0.001 0.0001 0.0010 0.10 0.00008 0.01 93 0.02 0.35 Collection Ponds 95%ile1 RS Runoff (Development) 6.7 0.194 0.001 0.001 0.001 0.0001 0.0010 0.19 0.00008 0.02 492 0.07 1.69 Notes: Units are in mg/L unless stated otherwise. 1 Given pH is based on the 5th percentile

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