5 | P a g e Class 1 Storage Location Assessment_Oceana Gold NZ Ltd Wharekirauponga Underground Mine Appropriate separation distances have been considered (as per ‘ ANNEX M’ of IATG 2.20 ) between each explosive magazine/chamber, in order to mitigate risk of propagation by both potential rock spall and heat/ gas in the event of an unintended detonation. Each magazine chamber is estimated to have an internal volume of ~627m3. The total internal volume for the storage facility, including all magazine chambers and accessway, is ~6,089m3. This volume is considered during surface controlled zone calculations in the event of an unintended detonation. Figure 2 shows the underground magazine location set against the proposed mining plan. The site is conceptually located in the footwall of the orebody along one of the main access drives. The surface position directly above the proposed magazine location consists of remote and uninhabited forested area. The surface position above the proposed magazine facility is at approximately RL223 m. The proposed facility is located approximately 380 m below that surface position. ‘Figure 2 – Isometric view of proposed WUG underground magazine facility position’. Figure 3 shows the proposed facility layout. Separation distances are deemed appropriate in order to mitigate risk of propagation and mass detonation beyond a singular magazine chamber. A maximum stored capacity of 1,000 kg (NEQ) per magazine chamber has been used to estimate controlled zone offsets at all surface connections. ‘Figure 3 – Magazine chamber layout including separation distances and proposed stored quantities’. Proposed location of WUG underground magazine facility Varying surface connections where controlled zones apply. Magazine facility exit I.E Magazine Chamber (up to 100,000 units or 100 kg NEQ) 6 x Individual H.E Magazine Chambers (up to1,000 kg NEQ each) Magazine facility entry 10m
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