Supporting Technical Assessments

WSP New Zealand Limited 12 Moorhouse Avenue, Addington, Christchurch 8011, New Zealand T: +64 3 363 5400 wsp.com 17 June 2022 Reference No. G-01483.84-008-LR-Rev0_FINAL Phillip Jones OceanaGold Corporation Level 3, 99 Melbourne Street South Brisbane QLD 4101 Australia WKP MINE DEVELOPMENT: POST-CLOSURE STRUCTURAL CAPPING OF SHAFT OPENINGS Dear Phillip Introduction Golder Associates (NZ) Limited (Golder) (now WSP New Zealand Limited (WSP)] has prepared this preliminary design for post-closure structural capping/backfilling for the five mine shaft openings at Wharekirauponga (WKP) Mine, part of the Waihi North Project at the request of OceanaGold Corporation (OceanaGold). This letter report1 has been prepared by Golder-WSP under the terms and conditions of the existing Master Consulting Agreement between OceanaGold and Golder for the WKP project (OGN-2891). Shafts Proposed for the WKP Mine We understand that development of the WKP mine will include five shafts connecting the mine and access tunnels to the surface. These are:  A 250 m deep ventilation shaft (Shaft 1) on the Willows Road farm property, approximately 1200 m from the mine portal. This location is accessible from current farm tracks.  The remaining shaft locations are located within Coromandel Forest Park and are not accessible via surface roads. These include: ▪ A 400 m deep ventilation shaft (Shaft 2) approximately 4000 m from the portal. ▪ Three shafts at the WKP orebody: − A 110 m deep egress/escape shaft (Shaft 3). − A 215 m deep fresh air raise (FAR – Shaft 4) to supply fresh air to the exploration tunnels. 1 This letter report is provided subject to the attached Report Limitations.

RkJQdWJsaXNoZXIy MjE2NDg3