Supporting Technical Assessments

Golder Associates (NZ) Limited Level 1, 214 Durham Street, Christchurch 8011, New Zealand T: +64 3 377 5696 F: +64 3 377 9944 Golder and the G logo are trademarks of Golder Associates Corporation golder.com 08 September 2021 Reference No. 20148384_7407-012-LR-RevA_DRAFT Rory McNeill OceanaGold Corporation Level 3, 99 Melbourne Street South Brisbane QLD 4101 Australia WAIHI NORTH PROJECT: REVIEW OF EXISTING GEOLOGICAL INFORMATION FOR PROPOSED TUNNEL FROM WAIHI POLISHING PONDS PORTAL TO WILLOWS ROAD FARM Dear Rory 1.0 INTRODUCTION Golder Associates (NZ) Limited (Golder) has prepared this letter report1 at the request of OceanaGold Corporation (OceanaGold) addressing the expected geological conditions for five tunnel alignments from Waihi polishing pond site (Portal) to Willows Road Farm (Willows Connection). The Wharekirauponga (WKP) resource is located approximately 10 km north of the township of Waihi. The WKP resource and most of the proposed exploration tunnel, which will be used to access the ore body, lie beneath Department of Conservation (DoC) land within the WKP Minerals Mining Permit (60541) area. The portal for the proposed exploration tunnel will be located on Willows Road Farm, several kilometres from the ore processing plant at Waihi. This assessment considers the likely ground conditions for a proposed tunnel extending between Willows Road Farm and Waihi, based on existing geological information provided by OceanaGold. Several tunnel alignment options that have been prepared by OceanaGold run from a portal at the Waihi polishing pond site (referred to as ‘Portal’ in this report), under a number of different surface landholders, to ventilation shaft 1 located on the Willows Road Farm (referred to in this report as ‘Willows Connection’). The purpose of the tunnel is to allow the ore mined from WKP to be efficiently transported underground to the processing plant at Waihi instead of using surface roads from Willows Road Farm to Waihi. This letter report has been prepared by Golder under the terms and conditions of the existing Master Consulting Agreement between OceanaGold and Golder for the WKP project (OGN-2891). 1 This letter report is provided subject to the attached Report Limitations. D R A F T

RkJQdWJsaXNoZXIy MjE2NDg3