Supporting Technical Assessments

16 | P a g e Class 1 Storage Location Assessment_Oceana Gold NZ Ltd Wharekirauponga Underground Mine Controlled Zone Offset Table in Relation to Surface Ventilation Shafts and Portal Location ID and Description Calculated Volume Available Vulnerable Facilities (2 kPa Eq.) IBD/ PTRD (5 kPa) Interior of Buildings (9 kPa) Public Places/ Low density traffic routes (13 kPa) PBD (24 kPa) Site P0 Willows Rd Farm Portal 642,338 m3 <1 m <1 m <1 m <1 m <1 m Site P1 Willows Rd Farm, Fresh Air Intake 611,519 m3 <1 m <1 m <1 m <1 m <1 m Site P2 WUG FAR #1 114,933 m3 3.8 m 3.5 m 2.9 m 2.3 m <1 m Site P3 WUG RAR #2 90,229 m3 4.7 m 4.4 m 3.7 m 2.9 m <1 m Site P4 WUG Fresh Air Intake 109,839 m3 3.9 m 3.7 m 3.0 m 2.4 m <1 m Table 1 – Controlled zone offset distances specific to each surface connection. Distances shown in above table are measured from the outer diameter of the surface portal/ ventilation shaft in which the controlled zone would apply. Total volume used for controlled zone calculations varies according to the surface connection being considered. 6 Additional Regulatory Compliance for Class 1 Storage Facilities The ‘ Health and Safety at Work (Hazardous Substances) Regulations 2017’ stipulate requirements for a PCBU in relation to mitigating risk from storage of class 1 substances. These include, but are not limited to the following items. • Part 5 – Emergency Management. • r 9.5 - Controlled substances licence generally required for class 1 substances. • r 9.11 – Limits on impact or pressure shock. • r 9.12 - Limits on spark energy. • r 9.13 - Limits on heat and fire. • r 9.14 - Limits on static electricity in relation to equipment. • r 9.15 - Protection from stray electrical currents. • r 9.16 - Protection from electromagnetic radiation. Compliance with the above stated regulations can be managed by way of industry best practice. In addition to compliance with ‘ HSW (Hazardous Substances) Regulations 2017 ‘, further storage facility design requirements can be referenced in ‘ AS 2187.1 - Section 2.6 ‘Underground Storage’. Additional requirements are summarised below; • Magazine chamber design (also refer AS 2187.1 for build specification). • Security requirements. • Signage requirements. • Emergency response and evacuation (engagement with FENZ if required). • Earthing requirements. • Qualification, training and competence of class 1 handlers.

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