OceanaGold’s high-grade New Zealand find: mine design and resource notes for engineers
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
OceanaGold’s latest drilling at the Wharekirauponga low-sulphidation epithermal system, 10 km north of Waihi on New Zealand’s North Island, has defined a new high-grade zone on the southern extent of the East Graben vein, with hole WKP144A returning 5.4 m at 25.8 g/t Au from 483 m and WKP144B cutting 14.9 m at 16.3 g/t Au from about 467 m. The emerging zone spans roughly 150 m of strike and remains open, complementing December 2025 resources of 2.63 Mt at 17.3 g/t Au (1.46 Moz) measured and indicated plus 2.9 Mt at 8.5 g/t Au inferred (800,000 oz). OceanaGold is running three drill rigs, with two more due in Q2, and is studying an underground mine that would tie into existing Waihi infrastructure, subject to permitting and further definition drilling.
Technical Brief
- East Graben mineralisation now traced over ~1.4 km strike with multiple discrete high-grade shoots.
- Wharekirauponga is a low-sulphidation epithermal gold–silver vein system, 10 km north of Waihi.
- December 2025 resource: 2.63 Mt measured and indicated at 17.3 g/t Au (1.46 Moz contained).
- Inferred resource stands at 2.9 Mt grading 8.5 g/t Au for 800,000 oz contained gold.
- Current drilling aims both to convert existing resources to reserves and to extend the mineralised footprint.
- Three rigs are operating on site, with two additional rigs scheduled to start in Q2 2026.
- Development concept envisages an underground mine tied into existing Waihi infrastructure to minimise new surface facilities.
- Continued step-out drilling on open structures suggests further resource growth potential along and across strike.
Our Take
With Wharekirauponga sitting just 10 km from the existing Waihi operation, the previously reported A$200 million underground development contract for the Waihi North project (Dec 2025 item) suggests OceanaGold is already committing to the access and infrastructure needed to turn these high-grade intercepts into mineable inventory.
The very high measured and indicated grades at Wharekirauponga position OceanaGold at the lower end of the cost curve within our gold coverage, which could partially offset the margin squeeze flagged in the March 2026 analysis of oil-driven cost pressure on open-pit gold miners.
Running three drill rigs and planning to lift that to five in the second quarter signals an aggressive resource-definition phase; for practitioners this typically means near-term updates to mine plans and potential re-optimisation of the underground development sequence already contracted at Waihi North on New Zealand’s North Island.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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