Supporting Technical Assessments

15 | P a g e Class 1 Storage Location Assessment_Oceana Gold NZ Ltd Wharekirauponga Underground Mine • Where controlled zone is located on OGNZL property, this can be managed by way of OGNZL ERP and evacuation plans. • In the event of an emergency situation, all OGNZL personnel within this zone shall evacuate to 5 kPa controlled zone (minimum). Controlled zone definition – 5 kPa r 9.27(2)(c)(i) - public traffic routes of high density, areas of high intensity land use, or any area where a person may be legally present inside the boundary of the place where the hazardous substance location is located are not subject to any of the following: i. a blast overpressure more than 5 kPa. Formula for minimum offset distance in accordance with the above criteria – D = 77 x HD x LD 1/3 Proposed class 1 site - Compliance summary for 5 kPa controlled zone. • Applies to any person legally inside boundary of OGNZL owned land, whether employees or members of the public irrespective of number or density. • Does not apply to 5 kPa controlled zones surrounding surface connections in public areas (DOC Reserve or HDC paper road) as this is a public place, and is not ‘inside the boundary’. • The controlled zone at surface connections on public places (DOC Reserve or HDC paper road) does not cross into any public high density traffic routes or area of high intensity land use. • Where controlled zones cross into public areas (either DOC Reserve or HDC paper road) there is no impact. • Where controlled zone is located on OGNZL property – this can be managed by way of OGNZL ERP and evacuation plans. The emergency muster location must be outside this area. Controlled zone definition – 2 kPa. r 9.27(2)(d) - vulnerable facilities are not subject to more than a blast overpressure of 2 kPa. Formula for minimum offset distance in accordance with the above criteria – D = 83 x HD x LD 1/3 Proposed class 1 site - Compliance summary for 2 kPa controlled zone. • There are no vulnerable facilities where 2 kPa controlled zones cross into public land (DOC Reserve or HDC paper road). Surface connection controlled zones within those public areas would be fully compliant. • There are no vulnerable facilities with controlled zones on OGNZL property. 5.4 Controlled Zone Offsets Applicable to Surface Connections In the event of an unintended detonation of stored substances within a singular magazine chamber containing 1,000 kg (NEQ) of H.E, the estimated controlled zones shown in Table 1 would apply to each surface connection. Controlled zone calculations have been based upon proposed dimensions at the surface portal connection of 5.0 m x 5.5 m and a diameter at all surface ventilation shafts of 5.50 m.

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