Aureka (ASX:AKA) clocks 455koz gold as the Tenacity discovery rewrites the Irvine model

A 26% resource jump at higher grade puts the Stawell Corridor story on a credible 1Moz path

Aureka (ASX:AKA) has lifted its global JORC Resource by 26% to 455koz of gold, the first revision to the flagship Irvine Gold Project since the 2021 maiden estimate. The kicker is that the headline grade also moved up, not down. Irvine now sits at 398koz inferred at 2.59g/t, a 30% lift in ounces and a 6% lift in grade over the prior estimate.

Since Aureka began operations in January 2025 with 304koz on the books, global resources have grown 50%. That growth has come from roughly 5,000 metres of diamond drilling across eight holes, which is a tight metres-per-ounce ratio for a brownfield Victorian gold play.

What is different here is that Aureka is now compounding on an existing resource with high-grade intercepts and a re-interpreted structural model. The Tenacity Fault, discovered in late 2025, is doing most of the heavy lifting and changes how investors should think about the path to 1Moz.

The Tenacity Fault is the discovery that actually drove the upgrade

Of the 94koz added at Irvine, the bulk traces back to a single piece of geological work. A review of the drill core showed that the Tenacity Fault and associated structures dip moderately west at 45 to 60 degrees, not steeply as previously assumed.

That re-interpretation generated 11 mineralised domains within the Resolution Lode, with the Tenacity Fault zone alone contributing 112koz. Two thirds of those ounces sit underground, which matters because higher-grade underground tonnes carry better economics than shallow open pit material.

The Resolution Fault zone remains the anchor at 177koz. We think the more interesting line in the table is the VG domain at 55g/t, which speaks to the visible gold intercepts reported in October 2025.

Why the grade move matters more than the ounce move

Resource growth at flat or declining grade is the standard outcome for most ASX explorers as they drill out cheaper material on the margins. Aureka has done the opposite. Irvine’s grade lifted from 2.43g/t to 2.59g/t while tonnes rose 23%.

For context, the nearby Stawell Gold Mine, 16km north, runs a conventional crush-mill-CIL flowsheet with 80 to 90% gold recoveries on similar-style mineralisation. Aureka has not yet completed metallurgical testing, but the geological analogue is close enough that benchmark assumptions are defensible.

Managing Director James Gurry was explicit that grade is the focus going forward. With infill drilling underway at the St Arnaud Comstock project, the next test is whether some of that resource can be elevated above inferred status.

The entire resource is still inferred, and that is the real overhang

Every ounce booked at Irvine sits in the inferred category, classified that way because of wide-spaced drilling, the use of air core data in upper zones, and sub-optimal drill angles relative to the newly understood mineralisation orientation.

Our concern is that moving from inferred to indicated typically requires tighter drill spacing and orthogonal angles to the moderately west-dipping structures. That is more metres, more cost, and more time before the resource carries the confidence needed for a scoping study.

The dual-rig program currently operating is the right response. Whether the cash position supports a sustained drilling cadence over the next 12 to 18 months will determine how fast the inferred ounces start converting.

The Investors Takeaway for Aureka

The Irvine upgrade is a genuine piece of geological work, not a paper exercise. Adding 94koz at higher grade off eight diamond holes is the kind of efficiency that should keep institutions interested in the Stawell Corridor story, particularly with the Stawell Gold Mine operating just 16km north.

The next 12 months come down to whether Aureka can land indicated-status ounces at either Irvine or Comstock, and whether the exploration targets at the Resolution and Tenacity intersection deliver another step-change. Readers can see our prior coverage of small-cap resource names at stocksdownunder.

If those questions break the right way, the path from 455koz to the 1Moz target Jozef Story has been incentivised against starts looking less like ambition and more like sequencing.