Greatland Resources Ltd (AIM:GGP, ASX:GGP) has reported a significant upgrade to its flagship Telfer gold-copper operation in Western Australia, increasing the mineral resource by 150% to 8.0 million ounces of gold.
The updated December 2025 estimate also lifts the combined Telfer and Havieron resource to 14.9Moz of gold and 645,000 tonnes of copper, while introducing a maiden resource at the O’Callaghans tungsten-copper-zinc-lead deposit, highlighting the scale of the company’s broader footprint in the Paterson Province.
Telfer drives growth
The expansion at Telfer was the key contributor, adding 4.8Moz of gold at an estimated discovery cost of just $5 per ounce.
Importantly, higher-confidence Measured and Indicated resources increased by 163% to 3.8Moz, strengthening the foundation for future mine planning and reserve conversion.
The updated resource spans multiple mining areas:
- West Dome Open Pit: 4.9Moz (+135%)
- Main Dome Underground: 2.2Moz (+225%)
- West Dome Underground: maiden 0.6Moz
- Stockpiles: 0.3Moz
This diversified resource base supports both operational flexibility and long-term production visibility.
Underground potential emerging
A key takeaway from the update is the growing importance of higher-grade underground zones.
The newly defined West Dome Underground (WDU) resource contains 0.6Moz at ~2.3 g/t gold, representing a new potential mining front. The zone is geologically similar to the existing underground operations and remains open in multiple directions, with further drilling planned.
Drilling momentum continues
The resource upgrade follows an intensive 2025 drilling campaign exceeding 134,000 metres, with a further 100,000 metres planned, aimed at both expanding resources and increasing geological confidence.
Overall, the update positions Greatland with a materially enhanced resource base, improved confidence levels, and a clearer pathway to long-term production growth.
Greatland Managing Director, Shaun Day, commented:
“Telfer and Havieron’s combined resource of 550Mt @ 0.84g/t Au & 0.12% Cu for 14.9Moz Au & 645Kt Cu has the potential to underpin a multi-decade, world class mining hub. Our investment in significantly increased drilling has delivered substantial organic growth, with the overall Telfer resource growing by 150% to 8.0Moz, and the higher confidence Measured and Indicated component by 163% to 3.8Moz.
“The growth includes a high-grade maiden resource at the West Dome Underground project, which shows significant potential for a new mining front at Telfer and remains the focus of ongoing drilling.
“This strong resource update has been delivered by Greatland’s dedicated technical team who have executed an accelerated and extensive Telfer drilling program since taking ownership in December 2024.
“The significant growth in Measured and Indicated Resources, particularly at the West Dome Open Pit, is very pleasing with this material being of adequate geological confidence to be evaluated as part of our upcoming Ore Reserve estimate, which remains targeted for the June 2026 quarter.
“The scale of Telfer’s resource demonstrates clear potential to fully utilise our low cost 20 million tonne per annum processing infrastructure well into the future. The technical team’s focus is now to advance our higher grade opportunities including the West Dome Underground and the potential to restart Main Dome Underground’s sub-level cave, which could augment our development of Havieron.”
