EGL Ref: 9215 23 June 2022 Page 64 This report shall only be read in its entirety. File: WAI-985-000-REP-LC-0002_Rev0.docx TABLE 10: POTENTIAL PROJECT OPTIONS FOR TAILINGS STORAGE AND MINE OVERBURDEN DISPOSAL Option Tailings Storage Locations Mine Overburden Disposal Locations Rehabilitation Considerations Other Considerations No. Description 1 Base Case (Company Preferred Option) Storage 3 Tailings Slurry TSF to RL155 and GOP Tailings Slurry TSF Storage 3 TSF Tailings Slurry RL155 6.8Mt GOP TSF Tailings Slurry 2.1Mt Storage 3 TSF RL155 12.0Mt GOP TSF Backfill 5.3Mt UG Backfill WUG 4.7Mt MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (4.7Mt remaining in closure) GOP TSF dry cap or pond/wetland Impacts SNA at Storage 3 TSF 2 Maximise Storage 3 Tailings Slurry TSF to RL160 and GOP Lake Storage 3 TSF Tailings Slurry RL160 10Mt Storage 3 TSF RL160 16.8Mt UG Backfill WUG 4.7Mt MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (5.2Mt in closure) GOP Lake Impacts SNA at Storage 3 TSF 3 Storage 3 Dry Stack TSF and GOP Tailings Slurry TSF Storage 3 TSF Dry Stack RL162 12.6Mt GOP TSF Tailings Slurry 2.1Mt Storage 3 TSF Dry Stack RL162 10Mt GOP TSF Backfill 5.3Mt UG Backfill WUG 4.7Mt MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (6.7Mt in closure) GOP TSF dry cap or pond/wetland Storage 3 dry stack avoids SNA. Management of water surface water and erosion is a notable risk in the Waihi climate. Requires tailings slurry discharge to existing TSFs or new GOP TSF. Closure capping. 4 Storage 2 Raise to RL176 Tailings Slurry TSF Storage 2 TSF Tailings Slurry RL176 9.0Mt Storage 2 TSF RL176 13.2Mt UG Backfill WUG 4.7Mt MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (8.8Mt in closure) GOP Lake Avoids SNA Conveyor loadout requires relocation to bottom of Storage 2 embankment. Site access road to Process Plant needs relocating. Scheduling issues with large amount of rock to be placed before storage capacity provided. 5 Underground paste backfill and GOP paste backfill and Reinstate Gladstone Hill GOP Paste backfill no liner 5.9Mt WUG Underground paste backfill 3.3Mt GOP Cap as hill 12.7Mt UG Backfill MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (14Mt in closure) Would require commencement of paste backfill in south end of GOP while mining of main pit continues, and unlikely to meet project scheduling requirements. Paste strength needs to be designed to avoid risks of underground in-rush 6 Underground paste backfill and GOP paste backfill and Rock cap of TSF1A and TSF2 GOP Paste backfill no liner 5.9Mt WUG Underground paste backfill 3.3Mt TSF1A Rock Cap 6.4Mt TSF2 Rock Cap 6.4Mt UG Backfill MUG 4.4Mt Northern Rock Stack Stage 1 Up to 14Mt (13.9Mt in closure) Same issues as Option 6 regards paste backfill into GOP. (i.e., project scheduling and underground in-rush risk)
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