EGL Ref: 9215 23 June 2022 Page 57 This report shall only be read in its entirety. File: WAI-985-000-REP-LC-0002_Rev0.docx. 9.2.6.3. Northeast of Storage 2 A rock stack can be constructed northeast of Storage 2 in the same locality as a potential TSF. It is adjacent Golden Valley and Trig Roads. Preliminary geotechnical investigations have been undertaken and pre-feasibility designs have been prepared. Constraints include that the land is not owned by OceanaGold, it would impact on a new area and there would be additional affected stakeholders. 9.2.6.4. Northeast valley and upper northeast sites There are two options for small rock stacks that could be located immediately northeast of Storage 2. The first (Northeast valley) could be developed at the same location as the small TSF referred to in section 9.1.6.5. It would have the capacity to store about 3.5 Mm3. There is also another option immediately south of the Northeast valley (Upper northeast site). It would have small capacity. The advantage of these options is the proximity to the current conveyor/loadout. One disadvantage is the material would need to be hauled to a higher elevation than some other storage options and it would have high visibility from the northwest. Constraints include the land is not owned by OceanaGold and these options encroach into a SNA. 10.0 OPTIONS FOR ASSESSMENT 10.1. Category, Criteria and Weighting As per the Global Industry Standard on Tailings Management requirement 3.2 a multi criteria assessment (MCA), as a tool to compare the options, has been undertaken. Only feasible options that meet the project scheduling requirements have been considered. This reduces the number of viable options. The main categories that have been considered are summarised below: • Technical (e.g., geotechnical, geochemical, mine operations, constructability, operability) • Environmental (e.g., potential impacts on terrestrial and aquatic ecosystems, groundwater, surface water) • Socio-economic and permitting (potential social and economic impacts and benefits on communities, Mana Whenua, recreation, archaeological/heritage, and landscape/visual effects) • Project economics (short-term and long- term capital and operating expenses) For each category several subcategories have been defined. The weightings given to the main categories and their subcategories are summarised in Table 5.
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