Our Ref: 9215 23 June 2022 This report shall only be read in its entirety. File: WAI-985-000-REP-LC-0002_Rev0.docx TABLE A5. SCORING FOR OPTION 5 Option 5: Underground paste backfill and GOP paste backfill and reinstate Gladstone Hill Category Subcategory Category Weighting Subcategory Weighting Score Weighted score Category Score Final Score Comments Technical Future ore resource 0.25 0.1 3 0.3 Small risk that GOP TSF may affect future underground mining Geotechnical 0.15 5 0.75 Storage 3 and Northern Rock Stack site has some weak material in foundations but they will be removed Geochemistry 0.15 3 0.45 Storage 3 and Northern Rock Stack will have controls for potential geochemistry effects that have worked to date and have been adopted and proven to work at other projects. GOP TSF controls are based on sound design concepts that have been applied at other sites, but not proven at Waihi Project with experience. Constructability 0.1 5 0.5 Experience with existing TSFs indicates that they can be constructed to meet Specifications. Similar materials will be used for the NRS. Operability 0.1 5 0.5 Storage 3 and GOP TSF can be operated in all conditions and without interference from other site functions. Assumes haul road from Northern stockpile to GOP TSF will be independent of existing access road/bridge to Process Plant. Storage capacity and expansion potential 0.15 5 0.75 Storage 3 can be constructed in the future. GOP TSF could be expanded as a mine open pit overburden disposal area with rock placed above tailings Project schedule 0.25 3 0.75 Unlikely to meet scheduling requirements for talings. 4 1 Environmental Terrestrial ecosystem 0.25 0.2 3 0.6 Some short term impact on on-site terrestrial ecosystem associated with construction and operation of Storage 3 and GOP TSF. Biodiversity associated with closure plan would provide long-term mitigation. Aquatic ecosystem 0.2 3 0.6 Minor impact on aquatic ecosystem No known historical impact Groundwater 0.15 5 0.75 Potential groundwater impacts expected to be controlled with proposed design for facilities and considering performance of existing facilities Surface water 0.15 5 0.75 Potential surface water impacts expected to be controlled with proposed design for facilities and considering performance of existing facilities Impact on SNA 0.1 3 0.3 Storage 3 has small impact on SNA Dust 0.1 5 0.5 Control measure required and operating history indicates that air discharge standards will be met. Noise 0.1 3 0.3 Storage 3 is new TSF, located closer to some rural properties east of the Development Site. Expect minor noise effects, but no operating history at this location. 3.8 0.95 Socio-economic and permitting Social impact 0.25 0.15 5 0.75 Low social impact Mana Whenua 0.25 3 0.75 Consultation undertaken, but Mana Whenua prefer backfilling to recreate maunga rather than use as a TSF. Economic 0.1 5 0.5 Project has considerable economic benefit to community and other parties Recreation 0.1 5 0.5 No impact on recreational users Regulatory approval 0.2 3 0.6 Project has effects that can be mitigated. Archaeological/heritage 0.1 5 0.5 Some remnants of historical mining activities at GOP TSF, but not significant Landscape and visual 0.1 3 0.3 Some visual impact from construction of Storage 3 and Northern Rock Stack, but rehabilitation provides long-term mitigation 3.9 0.975 Project Economics Land ownership 0.25 0.1 5 0.5 OGNZL owns all the land required Capital cost 0.35 1.5 0.525 Ranks 4 = and score reflects this Operating cost 0.35 0 0 Ranks in bottom third Closure and post-closure cost 0.2 0 0 Ranks in bottom third. High cost to recreate Gladstone Hill 1.025 0.25625 TOTAL WEIGHTED SCORE: 3.181
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