Supporting Technical Assessments

GHD | Oceana Gold New Zealand Ltd. | 12552081 | Waihi North Project D-5 Table 5 Mataura Stream 1 Analytes Units Count Minimum Maximum Mean Median Alkalinity - Total g/m3as CaCO3 12 6.8 29 13 13 Aluminium-Dissolved g/m3 4 0.019 0.049 0.032 0.029 Antimony-Dissolved g/m3 3 0.0002 0.0002 0.0002 0.0002 Arsenic-Dissolved g/m3 4 0.001 0.001 0.001 0.001 Bicarbonate g/m3at 25°C 4 8.3 36 16.6 15.5 Boron-Dissolved g/m3 4 0.008 0.011 0.009 0.009 Cadmium-Dissolved g/m3 19 0.00005 0.00005 0.00005 0.00005 Calcium-Dissolved g/m3 19 1.54 4.2 2.6 2.4 Chloride g/m3 3 8 9 9 9 Chromium-Dissolved g/m3 3 0.0005 0.0005 0.0005 0.0005 Cobalt-Dissolved g/m3 12 0.0002 0.0002 0.0002 0.0002 Copper-Dissolved g/m3 19 0.0005 0.0005 0.0005 0.0005 Electrical Conductivity mS/m 21 5.36 10.5 7.0 6.6 Hardness-Total g/m3as CaCO3 19 7.8 21 13 12 Iron-Dissolved g/m3 19 0.02 0.3 0.06 0.04 Lead-Dissolved g/m3 19 0.0001 0.0001 0.0001 0.0001 Magnesium-Dissolved g/m3 19 0.96 2.5 1.5 1.4 Manganese-Dissolved g/m3 19 0.0012 0.026 0.0065 0.0027 Mercury-Dissolved g/m3 17 0.00008 0.00008 0.00008 0.00008 Molybdenum-Dissolved g/m3 15 0.0002 0.0002 0.0002 0.0002 Nickel-Dissolved g/m3 19 0.0005 0.0005 0.0005 0.0005 Nitrate-N g/m3 19 0.017 1.41 0.27 0.16 Nitrate-N + Nitrite-N g/m3 19 0.018 1.42 0.28 0.17 Nitrite-N g/m3 19 0.002 0.1 0.019 0.002 pH pH units 21 6.3 7.78 7.1 7.1 Potassium-Dissolved g/m3 12 0.82 2.9 1.4 1.185 Sodium-Dissolved g/m3 12 6.7 9.7 7.58 7.15 Sulphate g/m3 3 9 9 9 9 Zinc-Dissolved g/m3 19 0.001 0.005 0.0020 0.0014

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