Supporting Technical Assessments

Oceana Gold Project Quattro Project Quattro Geochemical Assessment – Tailings and Overburden, Treatment and Mitigation \\na.aecomnet.com\lfs\APAC\Christchurch-NZCHC1\Legacy\Projects\605X\60544823\6. Draft Docs\6.1 Reports\Waihi North\App F - PHREEQC Outputs\WNP_App F_PHREEQC_25.05.22.docx Revision 5 – 07-Aug-2020 Prepared for – Anderson Lloyd – Co No.: 5719274 • Scenario 4 – TSF2 – 95 %ile (known porewater geochemistry) x TSF2 Storage trace element correction factor The speciation modelling inputs ran the following steps, 4. Solution 1 was calculated based on factoring existing TSF data by trace element increases in Gladstone and WUG ore and the proportion placed with the respective TSF. 5. Equilibrium phases: CO2(g), Ferrihydrite, Alunite, K-Jarosite, FeAsO4:2H2O, Galena, Gibbsite, Cu(OH)2 6. Sorption of hydrous ferric oxides The greater of modelled values and existing TSF data is presented .

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