Oceana Gold Waihi North Project Waihi North Project Geochemical Assessment – Geochemistry of Tailings and Overburden, Treatment and Mitigation Revision 0 – 17-Jun-2022 Prepared for – Oceana Gold (New Zealand) Limited – Co No.: 2274246 11 AECOM Table 3 Summary of Geochemical Results for Rock – Historical Rock Arithmetic Mean Range Arithmetic Mean Range Arithmetic Mean Range Arithmetic Mean Range Trio Favona Martha Correnso North Wall Data MUG Rex MP4 Acid Generating Potential Total Sulphur (%) 2.1 0.5 - 5.1 2.3 0.01 – 6.0 3.0 0.01 – 9.3 2.15 0.47 - 3.39 0.03 6 6 6 6 6 4 5 6 Total Carbon (%) 0.3 0.02 - 0.7 - - - - 0.70 0.21 - 1.53 - - - - - - - - - MPA (%CaCO3) 6.5 1.5 – 15.9 7.0 0.03 – 19 9.5 0.03 – 29 6.7 1.5 - 10.6 - - - - - - - - - ANC (%CaCO3) 7.8 <2 – 15.0 1.5 0.03 – 13 3.1 <2 – 16 7.3 2.0 - 15 - - - - - - - - - ANC/MPA 1.6 0.13 - 8.12 1 0.004 – 32 0.9 0 – 18 1.36 0.2 - 4.6 - - - - - - - - - AP (kg CaCO3/tonne) 65 15 - 159 70 0.3 - 190 112 0.3 - 291 67 14.7 - 106 - - - - - - - - - NP (kg CaCO3/tonne) 53 (26) 2 20 - 150 (1.7 - 58.7)2 15 0.3 - 130 31 <2 - 155 58 17.5 - 127 - - - - - - - - - NNP (kg CaCO3/tonne) -41 -152 - 43 -54 -181 - 114 -73 -252 – 63 -15 -87.8 - 72.5 - - - - - - - - - NAG pH - - - - 3.4 2.1 - 7.5 8.7 2.3 - 11.2 - - - - - - - - - Major Elements Aluminium (%) 7.1 6.02 - 8.06 4.6 0.5 – 10 7.4 0.7 – 12 7.3 6.2 - 8.2 8.2 0 0 0 0 - 0 0 0 Iron (%) 3.7 2.79 - 4.72 3.0 0.9 – 6 3.4 0.2 – 6 3.5 3.1 - 4.3 4.1 0 0 0 0 - 0 0 0 Calcium (%) 1.4 0.17 - 3.54 0.4 0.01 – 4 1.1 0.03 – 6 2.3 1.2 - 4.2 4.1 0 0 0 0 - 0 0 0 Magnesium (%) 1.8 0.44 - 2.71 0.7 0.01 – 2 1.6 0.01 – 4.5 1.7 1.3 - 2.2 2.3 0 0 0 0 - 0 0 0 Sodium (%) 0.8 0.08 - 1.57 0.1 < 0.01 – 1.6 0.4 <0.01 – 2.1 1.0 0.5 - 1.7 2.3 0 0 0 0 - 0 0 0 Potassium (%) 3.4 1.48 - 5.51 1.7 0.1 – 3.5 2.7 0.3 – 5.6 4.9 2.1 - 6.2 2.1 0 0 0 1 - 0 0 0 Trace Elements Antimony 2.4 1 - 7.07 24 1.0 – 118 6 0.02 – 50 12.8 0.7 - 51 0.2 3 6 4 5 - 2 3 3 Arsenic 30.1 6 - 99.6 94 15 – 540 26 1.2 – 78 58.4 19 - 164 1.5 4 5 4 5 - 3 2 3 Barium 546 90 - 710 209 20 - 720 347 34 – 980 796 520 - 981 500 0 0 0 0 - 0 0 0 Cadmium 0.16 0.04 - 0.4 0.25 0.03 – 4 0.1 <0.02 – 0.6 0.69 0.1 - 3 0.1 0 1 0 2 - 0 0 0 Cobalt 16.5 12.3 - 24 15 2 – 32 21 0.8 – 57 19.1 12.1 - 29 20 0 0 0 0 - 0 0 0 Chromium 150 50 - 281 163 44 – 392 146 81 – 277 75.1 51 - 125 100 0 0 0 0 - 0 0 0 Copper3 24.9 12.6 - 61.8 39 11 – 380 29 8 – 150 24.7 2 - 88 50 0 0 0 0 - 2 2 3 Lead 23.2 8.2 - 132 41 4 – 1070 10 1 – 28 23.3 8 - 103 14 0 1 0 0 - 0 0 0 Mercury 0.15 0.01 - 0.9 0.75 0.06 – 4.5 0.4 0.04 – 2 0.05 0.025 - 0.099 0.05 1 3 2 0 - 0 2 2 Manganese 915 94 - 1450 294 26 – 1540 985 90 – 3400 1070 638 - 2731 950 0 0 0 0 - 0 0 0 Molybdenum 1.6 0.6 - 4.6 4 1 – 12 1.8 0.3 – 6 1.9 0.6 - 6 1.5 0 1 0 0 - 0 0 0 Nickel 31.8 13.4 - 66 14 6 – 27 57 7 – 159 25.9 14 - 39 80 0 0 0 0 - 0 0 0 Selenium 2.0 1 - 6 2.5 < 1 – 15 1.1 0.1 – 4 6.37 2 - 36 0.05 5 5 4 6 - 5 4 4 Vanadium 113 84 - 146 86 5 – 180 104 3 – 206 194 181 - 205 160 0 0 0 0 - 0 0 0 Zinc 92.6 44 - 227 96 7 – 1670 63 <2 – 152 82.6 31 - 201 75 0 0 0 0 - 0 0 0 Notes: Units are in mg/kg unless stated otherwise * Number of data points insufficient to generate meaningful value. Arithmitic mean (and lower bound of Range) assumes values reported at analytical detection limit are equal to analytical detection limit. 1. Bowen, HJM, 1979,Environmental Geochemistry of the Elements. 2. Geochemical Abundance Indices - The Gardguide version 0.7 - National Institute of Acid Prevention 3. Elevated mean Cu with respect to previous overburden is driven by outliers Bold Concentrations exceed the mean value for the earths crust. Red - Geochemical Abundance Indices of 3 or greater Data Directly Relevant to Project Martha and Project Quattro Parameter Trio Andesite Waste Rock Favona Andesite Waste Rock Martha Mine Waste Rock Correnso Andesite Waste Rock 27 Samples Mean Concentration in Earths Crust1 Geochemical Abundance Index2 25 Samples 85 Samples 46 Samples
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