AGC Hits 102g/t AgEq 540m Below Surface at Achilles, Doubling Resource Depth
AGC’s deepest hole at Achilles extends high-grade mineralisation 540 metres below surface
Australian Gold and Copper has reported results from the deepest hole ever drilled at its Achilles discovery in the South Cobar Basin, NSW. Hole A3DD014 returned 26m at 102g/t AgEq from 433m, confirming high-grade mineralisation approximately 540m down dip from surface and 250m below the base of the current Mineral Resource Estimate.
The result represents the strongest outcome from the recently completed depth-extension drilling programme, which targeted mineralisation beneath the existing resource envelope. A3DD014 intersected 15m at 153g/t AgEq from 433m, further including 2m at 770g/t AgEq from 440m. The intercept comprised 0.4g/t Au, 47g/t Ag, and 0.8% Zn+Pb across the broader 26m interval.
A second hole from the programme, A3DD016, returned 3m at 97g/t AgEq from 332m, including 1m at 130g/t AgEq from 333m. Both holes confirm the Achilles mineral system remains open and fertile at depth, materially extending the known mineralisation envelope beyond the existing 38.5Moz AgEq resource.
Glen Diemar, Managing Director
“A3DD014 is the deepest hole drilled at Achilles to date and has returned the strongest result from the recent depth-extension drilling programme. This is an excellent result and confirms the Achilles mineral system remains open and fertile hundreds of metres below the current resource.”
The drilling provides critical geological information for assessing underground mining potential and supports future resource additions to the underground component of the Mineral Resource Estimate.
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What is silver equivalent and why does it matter for polymetallic deposits?
Silver equivalent (AgEq) is a standardised metric used to express the combined value of multiple metals in a single figure. At Achilles, the deposit contains silver, gold, zinc, and lead, which makes direct grade comparisons difficult without a unified measure.
AGC applies the following formula to calculate silver equivalent: AgEq(g/t) = Ag(g/t) + 92.6×Au(g/t) + 32.1×Zn(%) + 21.8×Pb(%). This calculation is based on metal recoveries derived from metallurgical test work completed in August 2025: 83% for silver, 90% for gold, 95% for zinc, and 92% for lead.
The metal prices used in the calculation are US$31.6/oz for silver, US$2,700/oz for gold, US$2,850/t for zinc, and US$2,000/t for lead. These prices reflect 12-month averages and provide a consistent basis for evaluating drill results across the deposit.
Silver equivalent allows investors to compare polymetallic drill results using a single grade metric, making it easier to assess the quality of intersections and evaluate project economics. The conversion factors are transparent and based on recoverable sales assumptions, which means the AgEq figure represents the in-situ value of the combined metals.
Drilling confirms Achilles mineralisation extends well beyond current resource
The current Mineral Resource Estimate at Achilles extends from surface to approximately 250m down dip. The depth-extension programme has now intersected mineralisation at least 540m down dip, more than double the resource depth. This materially de-risks the depth potential of the northern high-grade zone and supports future underground resource growth.
A3DD014 was drilled approximately 60m below and east of the first two deep step-out holes reported in July 2026 (A3DD013 and A3DD015). The hole targeted beneath a previously reported high-grade intercept in A3RCD089, which returned 11m at 424g/t AgEq from 305m, including 3m at 1,453g/t AgEq from 306m (reported January 2026).
The completed programme provides confidence for long-term planning as AGC assesses development options. By confirming mineralisation well below the current resource, the drilling supports the potential for future underground resource additions and provides additional geological information for assessing underground mining scenarios.
| Hole ID | Interval | AgEq (g/t) | From (m) | Key Metals |
|---|---|---|---|---|
| A3DD014 | 26m | 102 | 433 | 0.4g/t Au, 47g/t Ag, 0.8% Zn+Pb |
| A3DD014 (incl) | 15m | 153 | 433 | 0.6g/t Au, 80g/t Ag, 0.7% Zn+Pb |
| A3DD014 (incl) | 2m | 770 | 440 | 2.4g/t Au, 526g/t Ag, 0.9% Zn+Pb |
| A3DD016 | 3m | 97 | 332 | 0.6g/t Au, 8g/t Ag, 1.0% Zn+Pb |
| A3DD016 (incl) | 1m | 130 | 333 | 0.6g/t Au, 11g/t Ag, 2.2% Zn+Pb |
The step-out drilling materially de-risks the depth potential of the northern high-grade zone and supports future underground resource growth. The results provide further confidence as AGC assesses future mining potential and longer-term development optionality at Achilles.
Achilles hosts an initial 38.5Moz AgEq resource with strong growth potential
Resource breakdown by category and mining method
The existing Mineral Resource Estimate at Achilles stands at 38.5Moz AgEq (58% Indicated) across 10.3Mt at 116g/t AgEq. The resource starts at surface and extends to approximately 250m down dip, covering both open pit and underground mining scenarios.
The oxide component comprises 0.8Mt at 81g/t AgEq containing 2.0Moz AgEq. This near-surface oxide material is expected to be the focus of the next drilling phase, given its lower-cost development profile and faster drilling execution. The open pit Indicated resource totals 4.7Mt at 141g/t AgEq for 21.5Moz AgEq, while the underground Indicated resource comprises 0.3Mt at 130g/t AgEq for 1.1Moz AgEq.
23 recent drill holes were not included in the December 2025 Mineral Resource Estimate due to assay timing. These holes provide further upside potential for resource growth when incorporated into future updates.
Glen Diemar, Managing Director
“These deeper results are important for long-term planning. They provide further confidence as we assess future underground mining potential, resource growth and development options for the deposit.”
Key resource metrics:
- Total resource: 10.3Mt at 116g/t AgEq for 38.5Moz AgEq
- Open pit Indicated: 4.7Mt at 141g/t AgEq for 21.5Moz AgEq
- Underground Indicated: 0.3Mt at 130g/t AgEq for 1.1Moz AgEq
- 58% of resource classified as Indicated
AGC shifts focus to lower-cost oxide drilling and multi-project development
Near-term priorities at Achilles
The next phase at Achilles is expected to comprise shallow RC (reverse circulation) drilling targeting oxide gold-silver mineralisation. This approach is lower cost, faster to drill, and more directly aligned with near-surface resource growth compared to deep diamond drilling.
The programme will follow up on outstanding oxide results reported in September 2025. Hole A3OX010 returned 5m at 19.1g/t Au, 52g/t Ag and 1.3% Pb+Zn (1,851g/t AgEq) from 30m, within a broader interval of 42m at 266g/t AgEq from 26m. The near-surface oxide zone represents a lower-risk target with potential for rapid resource expansion.
Approvals are currently underway to support the shallow drilling programme. The shift in focus reflects AGC’s strategy of balancing long-term underground optionality with near-term, cost-effective resource growth.
Evergreen and regional exploration advancing
Diamond drilling continues at the Browns Reef–Evergreen deposit, with 16 holes completed and a 17th underway. RC drilling is expected to commence in August, targeting the shallow near-surface oxide zone. AGC is working towards an initial Mineral Resource Estimate at Browns Reef–Evergreen.
Results from the Tooronga aircore programme are being interpreted, with initial findings expected shortly. At Mount Illabo (Junee project), field activities have commenced, including soil sampling and drill permitting.
AGC is executing a multi-pronged growth strategy across its 2,600km² South Cobar landholding, with near-term resource growth catalysts at both Achilles and Evergreen. The company held A$7.1 million in cash as at 31 March 2026, with nil debt and 285 million shares on issue.
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Why the depth extension matters for long-term development
Confirming mineralisation well below the current resource provides critical geological information for assessing underground mining potential. The deeper results support future resource additions to the underground component of the Mineral Resource Estimate and extend the known strike and dip continuity of the system.
The completed programme provides confidence for long-term planning as AGC assesses development options. The deepest hole returned the strongest result from the programme, indicating the system remains fertile at depth and confirming the exceptional continuity of the Achilles mineral system.
Key strategic takeaways:
- Resource growth optionality: Mineralisation now confirmed 250m below the current resource base, materially extending the known envelope.
- Underground mining potential: Depth continuity supports future underground development scenarios and longer-term mining studies.
- Grade continuity: The deepest hole returned the strongest result from the programme, indicating the system remains fertile at depth.
Glen Diemar, Managing Director
“While the deeper results are highly encouraging, the next value-adding programme at Achilles is planned to focus on shallow RC drilling targeting oxide gold-silver mineralisation. This work is expected to be lower cost, faster to drill and more directly aligned with near-surface resource growth.”
The depth-extension programme has successfully demonstrated the scale and quality of the Achilles system. Future work will balance long-term underground optionality with near-term, cost-effective resource expansion at shallow depths.
Ready to Learn More About Australian Gold and Copper’s Achilles Discovery?
Australian Gold and Copper has just confirmed high-grade mineralisation 540 metres below surface at Achilles, materially extending the known envelope beyond the existing 38.5Moz AgEq resource. The deepest hole drilled to date returned 26m at 102g/t AgEq, demonstrating the system remains fertile hundreds of metres below the current resource base.
With shallow oxide drilling now prioritised for near-term resource growth and underground potential de-risked at depth, AGC is advancing a multi-pronged development strategy across its 2,600km² South Cobar landholding. Visit the Australian Gold and Copper investor centre to view the full drilling results and explore the company’s upcoming catalysts.