Supporting Technical Assessments

1 | P a g e Class 1 Storage Location Assessment_Oceana Gold NZ Ltd Wharekirauponga Underground Mine Table of Contents 1 Executive Summary 2 2 Introduction 3 3 Regulatory Compliance Considerations 4 4 Proposed WUG Underground Magazine Layout and Positioning 4 4.1 Blast Propagation by Rock Spall 6 4.2 Blast Propagation by Flame and Hot Gases 6 4.3 Other Considerations - Major Damage Prevention to Interior of Facility 7 5 Controlled Zones at Surface Connections (Portals and Ventilation Shafts) 7 5.1 Location of Surface Portals and Vent Shafts 8 5.2 Considerations in Establishing Surface Controlled Zones 12 5.3 Blast from Tunnel Entrance - Controlled Zone Effects 13 5.4 Controlled Zone Offsets Applicable to Surface Connections 15 6 Additional Regulatory Compliance for Class 1 Storage Facilities 16 7 Location Compliance and Magazine Certification Requirements 17 8 Conclusion and Summary 17 Terms and Definitions 18 Reference A – Legislative Framework within New Zealand 19 Reference B – Supporting Standards and Guidance 19

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