12 | P a g e Class 1 Storage Location Assessment_Oceana Gold NZ Ltd Wharekirauponga Underground Mine Based upon the proposed maximum stored capacity of 1000 kg (NEQ per chamber), the calculated controlled zone offset distance relevant to members of the public (13 kPa) is 2.4 m at this site. Given the publicly excluded area is limited to 10 m diameter, to achieve regulatory compliance with the 13 kPa limit at this location it is proposed that either: • The vent shaft diameter be limited to 5.25 m Ø; or; • The stored quantity of explosives per magazine be limited to 900 kg (NEQ). A combination of the above elements may also be considered during the final design phase of the project, whereby a moderate reduction in both shaft diameter and stored capacity could be implemented to achieve compliance with the 13 kPa limit. However, if a reduction in maximum capacity for magazine chambers is considered, it will be based upon ‘Site P3’ where the controlled zone offset distance relevant to members of the public is greatest. ‘Figure 8 – Aerial view of ‘P4 and P5’ surface connection located within HDC paper road’. 5.2 Considerations in Establishing Surface Controlled Zones. ‘ANNEX M, of IATG 2.20’ considers a number of factors when establishing a magazine location. The primary factor is the detonation mass in the event of an unintended detonation. This figure is then used in the estimation of the surface controlled zone offsets described in accordance ‘Health and Safety at Work (Hazardous Substances) Regulations 2017, r 9.27’. The proposed storage facility will store several types of explosive substances in order to meet operational needs. Some of these substances require segregation, which has been considered in the design. The proposed facility consists of the following quantities stored in seven separate magazine chambers. • Six magazine chambers will be utilised for varying commercial explosive substances (H.E) with up to 1,000 kg (NEQ) per magazine chamber. • One magazine chamber will be utilised for storage of up to 100,000 detonators (100 kg NEQ) of varying types. NORTH 60 m 13 kPa controlled zone for Sites P3 and P4 lies outside the proposed perimeter fence and would be deemed ‘noncompliant’ (illustrative only) Site P4 – WUG Fresh Air Intake Site P3 – WUG RAR #2 Forested area is DOC Reserve. White shaded area is HDC paper road All controlled zones indicated remain within HDC paper road boundary
RkJQdWJsaXNoZXIy MjE2NDg3