It's a strong start to the week for this ASX gold stock.
Greatland Resources Ltd (ASX: GGP) raced 10.45% higher to $10.78 during Monday morning trade, grabbing investor attention in a big way.
That's a welcome turnaround after a tough month that saw the share price slide 20% — although zooming out, it's still up an impressive 46% over the past year.
So, what's driving the surge?
Image source: Getty Images
Major resource upgrade
The answer lies in a major resource upgrade that has lit a fire under the stock.
Greatland revealed a 150% increase in Telfer's gold Mineral Resources to 8.0 million ounces. Even more eye-catching, the combined Telfer and Havieron resources now sit at a massive 14.9 million ounces of gold and 645,000 tonnes of copper.
This updated December 2025 Group Mineral Resource Estimate reflects a period of rapid growth, fuelled by extensive drilling since the last update. The company has been pushing hard to expand its resource base — and today's numbers suggest that strategy is paying off.
Importantly, the $6.5 billion ASX gold stock also continues to advance the Telfer operation itself. A strong drilling pipeline and the addition of high-grade underground resources are helping to build momentum.
Improving ore reserves
There's another key detail investors are getting excited about. The upgrade includes a significant lift in Measured and Indicated Resources — the higher-confidence categories.
That matters because it improves the ASX gold stock's ability to convert resources into ore reserves, which are critical for long-term mine planning and production visibility.
On top of that, updated cost and revenue assumptions — based on 2025 actuals and conservative commodity price forecasts — point to a solid economic foundation for the project.
Managing Director Shaun Day didn't hold back on the outlook:
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.
So what's next?
Greatland isn't slowing down. Following the substantial increase in both total resources and confidence levels, the company is now targeting an updated Telfer Ore Reserve Estimate in the June 2026 quarter. That could be another key catalyst.
At the same time, focus is shifting to higher-grade zones like the West Dome Underground and Main Dome sub-level cave, which could enhance project economics even further.
And there's more to come. A record drilling program is set to continue through the second half of FY26 and into FY27, with the aim of growing and upgrading resources even further.
ASX gold stock snapshot
Looking at the bigger picture, Greatland has been a standout performer. Over the past 12 months, the ASX gold stock has risen 46%, comfortably beating the S&P/ASX 200 Index (ASX: XJO), which is up around 9% over the same period.
Today's surge shows just how quickly sentiment can shift — especially when a miner delivers a blockbuster resource upgrade.
