Australian Gold and Copper Confirms Achilles Mineralisation Beyond 400 Metres

Achilles Goes Deeper: Australian Gold and Copper Confirms High-Grade Mineralisation Beyond 400 Metres

Australian Gold and Copper Ltd (ASX: AGC) has reported that step-out drilling at the Achilles deposit in New South Wales has confirmed mineralisation more than 200 metres below the current Mineral Resource Estimate (MRE), extending the system to beyond 400 metres down dip. This is a significant result because the current Achilles resource only extends to around 250 metres down dip, meaning recent drilling has tested well beneath the existing model.

The latest update covers results from two of four diamond drill holes designed to test the northern high-grade zone below the current resource. Assays remain pending for A3DD014 and A3DD016, which the company said should provide more information on continuity, geometry, and scale potential at depth.

What the Drilling Has Confirmed

The program was designed to test below A3RCD089, previously the deepest hole drilled into Achilles North. That earlier hole had returned 11 metres at 424 g/t AgEq from 305 metres, including 3 metres at 1,453 g/t AgEq from 306 metres.

The new step-out holes were planned at 100-metre spacings and drilled east of A3RCD089. The aim was not only to chase grade, but also to test whether the mineralised system continued at depth below the current resource envelope.

Two holes have now returned significant silver-gold-base metal mineralisation:

The significance of these holes is less about matching the standout result in A3RCD089 and more about proving that the Achilles system remains mineralised and open at depth. That distinction matters for investors assessing whether Achilles could support future growth in underground resource inventory.

The company also noted that A3DD012 was terminated at 274 metres due to drilling difficulties in fractured ground and was not considered an effective test of the target.

Managing Director Commentary

"These new results demonstrate that the Achilles mineral system remains open and fertile at depth, with mineralisation now confirmed beyond 400 metres down dip. Our confidence builds as we continue to demonstrate the scale potential of this deposit," said Glen Diemar, Managing Director.

"Importantly, assays from two further deep holes are still pending and will provide additional information on the scale potential of the system."

Why Depth Extensions Matter at Achilles

For resource investors, depth extensions can be highly relevant because they may indicate that an existing deposit is part of a larger mineralised system than initially modelled. In the case of Achilles, the current MRE starts at surface and extends to only about 250 metres down dip, while the latest drilling has intersected mineralisation roughly 200 metres below that boundary.

A deposit being described as open at depth means drilling has not yet defined the end of the mineral system in that direction. It does not guarantee a larger resource, but it does indicate that further drilling may add tonnes, grade, or both if continuity is confirmed.

Furthermore, AGC said the latest holes provide geological information that may help target higher-grade shoots deeper in the system. In practical terms, a high-grade shoot is a more concentrated part of the mineralised body where metal grades are stronger than the surrounding material.

Understanding Silver Equivalent for Investors

How Is Silver Equivalent Calculated?

AGC reports many Achilles results in silver equivalent (AgEq), which is a common way of expressing the combined value of several payable metals as a single grade number. At Achilles, that includes silver, gold, zinc, and lead.

This matters because Achilles is not a pure silver deposit. Some intervals may carry more gold, whilst others may be richer in zinc or lead. Silver equivalent allows investors to compare results across different zones using one headline metric.

According to the announcement, AGC used the following formula for drill results:

AgEq (g/t) = Ag (g/t) + 92.6 × Au (g/t) + 32.1 × Zn (%) + 21.8 × Pb (%)

The assumptions behind that formula were based on the company's reported metal prices and metallurgical recoveries:

Copper is not included in the AgEq calculation, because the company stated it was not recovered in the metallurgical testwork used for this formula.

For non-specialist readers, the key point is straightforward: a result such as 1 metre at 400 g/t AgEq combines the metal value from silver, gold, zinc, and lead into one number, making the result easier to compare with other intersections across the deposit.

AgEq in Plain Terms

Silver equivalent is a blended grade measure used in multi-metal deposits. It helps investors compare drill results by converting the value of different metals into one silver-based figure.

The Current Achilles Resource and What May Change Next

The existing Achilles Mineral Resource Estimate, referenced in the announcement from 16 December 2025, stands at 10.3 million tonnes at 116 g/t AgEq for 38.5 million ounces AgEq. Additionally, 58% of that resource is in the Indicated category, which is generally considered a higher-confidence classification than Inferred.

The current resource breakdown is summarised below:

The ASX release also breaks the resource down by material type:

Importantly, 23 recent drill holes were not included in the initial MRE due to assay timing. That means there is already a body of additional drilling that could be considered in a future resource update, subject to modelling and sufficient continuity.

The deeper drilling now being reported sits outside the current model, so these results may also help define future additions to the underground component if follow-up work supports that outcome.

AGC's Broader South Cobar Basin Programme

The Achilles update sits within a wider exploration and resource-building campaign across AGC's 2,600km² landholding in the South Cobar Basin. In the announcement, the company outlined several active programmes beyond the current depth extension drilling.

These include:

1. Pending Achilles depth assays — Results from A3DD014 and A3DD016 are still pending and are expected to add more information on the shape and continuity of the deeper system.

2. Planned shallow RC drilling at Achilles — The next phase is expected to target shallow oxide gold-silver mineralisation, including follow-up work on A3OX010, which previously returned 42 metres at 266 g/t AgEq from 26 metres, including 5 metres at 1,851 g/t AgEq from 30 metres. Approvals are underway for drilling from August 2026.

3. Browns Reef-Evergreen drilling — Diamond drilling continues at Evergreen, where AGC is targeting an initial MRE at the Browns Reef-Evergreen precious and base metal deposit. Further assays are expected in coming weeks.

4. Tooronga aircore interpretation — Results are being interpreted alongside microscopic work on bottom-of-hole samples, with initial findings expected shortly.

5. Junee field activities — Field work has started whilst historical database integration continues, with drill targeting advancing across priority prospects.

A simple summary of the near-term programme is outlined below:

What This Update Means for Investors

This announcement strengthens the geological case that Achilles is larger than its current resource envelope suggests. The latest drilling has confirmed that mineralisation continues well below the existing MRE, and the system remains open beyond 400 metres down dip.

However, there are still important uncertainties to consider. The latest grades are lower than the exceptional intercept previously reported from A3RCD089, and more drilling will be needed to determine whether deeper mineralisation can support a meaningful resource expansion. The pending assays from the remaining two holes are likely to be watched closely for that reason.

At the same time, AGC is not relying on Achilles alone. Drilling continues at Evergreen with the aim of establishing a second resource opportunity, whilst near-surface oxide targets at Achilles could add another layer of development optionality.

With 285 million shares on issue and $7.1 million in cash as at 31 March 2026, the company remains in an active exploration phase. For investors focused on ASX precious and base metals explorers, the immediate watchpoints are clear: pending deep Achilles assays, progress toward an updated resource pathway, and continued newsflow from Browns Reef-Evergreen.

In summary, the latest drilling does not yet define the full scale of the deeper Achilles system. What it does provide, according to the ASX update, is evidence that the mineralised system continues well beyond the current resource boundary — supporting AGC's stated focus on growing contained ounces across its South Cobar portfolio.

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