Astral Resources NL
- ASX Code: AAR
- Market Cap: $288,167,297
Drilling Into the Unknown: Visible Gold Nearly 400 Metres Below Theia's Current Resource
Astral Resources (ASX: AAR) has delivered an exploration and development update spanning every key value driver in its portfolio — and the headline result is compelling. Astral Resources visible gold at Mandilla Theia deposit sits nearly 400 metres below the current resource boundary, with depth extensions at its cornerstone Theia gold deposit, a strategic land acquisition to streamline the approvals pathway, and high-grade assay results from an adjacent satellite deposit all forming part of this significant update.
Together, these developments demonstrate a company actively building foundations for a major Western Australian gold project whilst simultaneously hunting for resource upside that could materially reshape its investment case.
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Drilling at Theia: What Has Been Found So Far?
The headline result centres on progress of a diamond drilling programme at the Theia deposit, the centrepiece of the 1.74 million ounce Mandilla Gold Project located approximately 70km south of Kalgoorlie in Western Australia.
Two of a planned six-hole (3,000 metre) diamond drill programme have now been completed, with both holes returning visually significant results that have encouraged the company to expand the programme.
Key details from the two completed holes:
- Hole AMRCD263 reached a final depth of 693.9 metres against a planned depth of 560 metres
- Hole AMRCD259 reached a final depth of 775.1 metres against a planned depth of 520 metres
- Both holes were extended beyond their original targets after geologists encountered significant quartz veining and visible gold
- Coherent zones of 10 to 20% quartz veining have been logged extending well beyond the current Mineral Resource Estimate (MRE) pit limits
- The deepest of the two completed holes extends almost 390 vertical metres below the current pit design
Assay results have been submitted to the laboratory with results anticipated during June 2026.
Managing Director Marc Ducler noted: "We have completed two holes to date and, pleasingly, our geologists have logged significant, consistent quartz veining and visible gold in the diamond drill core — suggesting that depth extensions of up to 380 metres below the current 1.4Moz MRE are a real possibility. While assay results remain pending, we have been extremely encouraged by these visual results and have added an additional three drill-holes to the programme."
Furthermore, the programme has been expanded from six holes (3,000 metres) to nine holes (5,500 metres) as a direct result of the encouraging visual results from the first two holes.
Understanding the Quartz Vein Proxy — Why Geologists Are Encouraged
What is a quartz vein percentage proxy?
In gold exploration, geologists often seek indicators of mineralisation whilst awaiting laboratory assay results, which can take weeks to return. At the Theia deposit, previous internal geological studies have demonstrated that gold mineralisation closely associates with elevated quartz vein percentages in the drill core.
In other words, the more quartz veining present in a given metre of drill core, the more likely that metre is to carry meaningful gold grades. This relationship has been tested and validated at Theia over many years of drilling and has been used directly to guide the mineralisation domain interpretation in the most recent MRE update (April 2026).
It is not a guarantee of economic gold grades — assays remain the definitive measure — but it represents a reliable and well-understood indicator specific to this deposit.
Why does this matter to investors?
When geologists log coherent zones of 10–20% quartz veining extending hundreds of metres below the current resource boundary — accompanied by visible free gold — it signals that the gold-forming geological system remains active at depth. This raises the possibility that the current MRE, which already stands at 1.74 million ounces for Mandilla, may represent only a portion of the total endowment.
The pending assay results in June 2026 will consequently provide a critical moment in quantifying whether that visual evidence translates into material resource upside.
Key glossary terms
| Term | Definition |
|---|---|
| MRE (Mineral Resource Estimate) | A JORC-compliant estimate of the quantity and grade of gold that can reasonably be expected to exist in a deposit |
| Diamond Drilling (DD) | A drilling method that retrieves a continuous cylinder of rock (core) for detailed geological logging and sampling |
| Quartz Vein Percentage | The proportion of a given metre of drill core that consists of quartz veins — used at Theia as a proxy for gold mineralisation |
| Visible Gold | Free gold that can be seen with the naked eye in drill core — an encouraging but not definitive indicator of grade |
| Open Pit Shell | The designed boundary of a proposed open pit mine, used to constrain resource reporting |
The Mandilla Homestead Acquisition: Removing a Potential Approvals Obstacle
In a pragmatic move to protect the development timeline for the Mandilla Gold Project, Astral has purchased the Mandilla Homestead — a 21-hectare parcel of freehold land situated approximately 500 metres from the proposed process plant location as outlined in the Mandilla Pre-Feasibility Study (PFS).
| Acquisition Detail | Information |
|---|---|
| Property | Mandilla Homestead (freehold land) |
| Size | 21 hectares |
| Purchase Price | $850,000 |
| Deposit Paid | $85,000 (paid 14 April 2026) |
| Settlement Date | On or around 10 August 2026 |
| Distance from Process Plant | ~500 metres |
The rationale is straightforward: by owning the land immediately adjacent to the proposed development, Astral removes the possibility that the project could be seen to negatively impact nearby residents during the approvals process. This simplifies the regulatory pathway without creating additional complexity.
There is also a practical secondary benefit. If the Mandilla project advances to operation, the homestead and its associated land and infrastructure would serve as an ideal exploration base, potentially enabling relocation of the existing core yard from its current location in the West Kambalda light industrial area.
Marc Ducler noted: "Understanding the potential scale and the future potential of the broader Theia mineral system is crucial as we finalise infrastructure footprint locations and complete the associated heritage clearance surveys. The purchase of the homestead will simplify the approval process removing the possibility that a development of Mandilla could impact any nearby residents."
High-Grade Results Confirmed at Spargoville's 5B Deposit
Alongside the Mandilla updates, Astral has reported assay results from a 12-hole, 1,517 metre RC drill programme completed in February 2026 at the 5B Deposit within the 100%-owned Spargoville Gold Project. The 5B Deposit currently hosts an Inferred MRE of 40,000 tonnes at 4.2 g/t Au for 5,000 ounces of contained gold.
The significance of the 5B Deposit extends beyond its current modest size. It sits immediately north of the proposed Theia waste rock landform and west of the proposed tailings storage facility for the Mandilla project. The company's view is that early mining of 5B could potentially allow the waste landform or tailings dam to expand into that area afterward — a practical piece of infrastructure sequencing that could add value to the overall project design.
Key assay results from the 12-hole programme:
| Hole ID | From (m) | Interval (m) | Grade (g/t Au) | Notable High Grade |
|---|---|---|---|---|
| SGRC148 | 108 | 9 | 4.38 | 2m at 10.3 g/t Au from 108m |
| SGRC154 | 97 | 4 | 8.31 | 1m at 29.1 g/t Au from 97m |
| SGRC144 | 100 | 4 | 4.95 | 1m at 13.4 g/t Au from 101m |
| SGRC150 | 103 | 5 | 3.32 | — |
| SGRC146 | 159 | 6 | 1.19 | — |
| SGRC142 | 102 | 5 | 1.62 | — |
| SGRC156 | 103 | 11 | 0.86 | — |
| SGRC158 | 142 | 10 | 0.71 | Confirms down-dip mineralisation |
| SGRC152 | 117 | 7 | 0.81 | — |
The results confirm the current geological interpretation and validate the existing mineralisation trend. Hole SGRC158 is particularly notable as it confirms mineralisation extends down-dip, with further work warranted given that deeper historical holes in that area intersected nickel mineralisation within the same shear zone.
Geologically, the high-grade component appears to be concentrated at the contact between a hangingwall ultramafic unit and a footwall basalt — a structurally controlled gold trap that the company's technical team is now better positioned to model. A reinterpretation of the mineralised wireframes and a broader Spargoville MRE update are scheduled for the September Quarter 2026.
Marc Ducler commented: "With confirmed high grade mineralisation in the recent results — including intercepts such as 2m at 10.3 g/t Au within a broader 9m intersection grading at 4.38 g/t Au, 1m at 29.1 g/t Au within a broader intersection of 4m at 8.31 g/t Au — there appears to be a clear high-grade component to the gold mineralisation at the contact of a hangingwall ultramafic unit with a footwall basalt."
The Bigger Picture: A Growing Resource Base Across Three Projects
To understand why each of these individual updates matters, it helps to view them in the context of Astral's consolidated resource and reserve position.
Group Mineral Resource Estimate (JORC 2012)
| Project | Tonnes (Mt) | Grade (g/t Au) | Contained Gold (oz) |
|---|---|---|---|
| Mandilla | 53.5 | 1.0 | 1,736,000 |
| Feysville | 5.0 | 1.2 | 196,000 |
| Spargoville | 3.0 | 1.4 | 139,000 |
| Total | 61.6 | 1.0 | 2,072,000 |
Group Ore Reserve Estimate (JORC 2012)
| Project | Tonnes (Mt) | Grade (g/t Au) | Contained Gold (oz) |
|---|---|---|---|
| Mandilla | 34.3 | 0.9 | 1,000,000 |
| Feysville | 2.3 | 1.2 | 88,000 |
| Total | 36.6 | 0.9 | 1,082,000 |
The group now holds a total MRE of over 2 million ounces across its three projects. The Mandilla Ore Reserve alone stands at 1 million ounces, underpinned by the PFS completed in June 2025 that outlined a standalone project producing 95,000 ounces per year for the first 12 years from a 2.75 million tonne per annum processing facility.
At the base case gold price assumption of $4,250 per ounce, the PFS demonstrated an NPV (8% discount rate) of $1.4 billion. At $6,250 per ounce, the NPV8 rises to $2.9 billion. The Theia depth extension drilling programme, if successful, has the potential to add further ounces to the already substantial Mandilla resource base — and given the depth the drilling is now reaching, those ounces could sit beneath the existing open pit economics rather than competing with them.
What's Coming Next: A Packed Pipeline of Catalysts
The near-term activity schedule is dense, with multiple work streams running in parallel.
Active programmes:
- Diamond drilling at Theia (expanded to 9 holes, 5,500 metres) — two holes complete, seven remaining; assays for first two holes expected June 2026
- RC infill drilling at Theia Stage 1 open pit — approximately 5,000 metres completed of the first phase (23,000 metres total) of a three-phase programme targeting a 12.5m x 12.5m drill density to increase Measured Resources ahead of mining
- Sterilisation drilling at Mandilla — continuing pending heritage clearance surveys
- RC and diamond drilling at Kamperman (Feysville) — planning underway following commencement of heritage clearance surveys in April 2026
Scheduled milestones:
| Catalyst | Expected Timing |
|---|---|
| Assay results from first two Theia DD holes | June 2026 |
| Mandilla Homestead settlement | On or around 10 August 2026 |
| Spargoville MRE update (including 5B reinterpretation) | September Quarter 2026 |
| DFS ongoing work programmes | Throughout 2026 |
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Why Astral Resources Warrants Investor Attention
Several factors distinguish Astral Resources from earlier-stage gold explorers:
- Scale already established. With a group MRE of over 2 million ounces and an Ore Reserve of 1.082 million ounces, the resource base has been defined to a level that supports serious development studies.
- PFS already completed. The June 2025 PFS demonstrated project-level economics with a base-case NPV8 of $1.4 billion, providing a credible financial anchor for the investment case.
- DFS underway. The company is actively advancing toward a Definitive Feasibility Study, with infill drilling, heritage clearance surveys, metallurgical testing, and infrastructure planning all progressing concurrently.
- Resource upside remains open. The Astral Resources visible gold at Mandilla Theia deposit targets a zone up to 380 metres below the current resource — entirely outside the existing MRE. If assays confirm the visual gold and quartz veining encountered, the resource growth story has material room to run.
- Satellite deposits add optionality. The 5B Deposit at Spargoville, whilst currently small, sits adjacent to planned infrastructure and carries high-grade intercepts. A resource update is scheduled for Q3 2026.
- Approvals pathway being actively managed. The Mandilla Homestead acquisition demonstrates a proactive approach to managing the development timeline, reducing the risk of delays from third-party impact objections.
- Gold price environment. The Mandilla PFS used a base case assumption of $4,250/oz. With the NPV8 reaching $2.9 billion at $6,250/oz, the project's economics are highly sensitive to gold price movements — and the current gold price environment provides a meaningful tailwind to those projections, though investors should note that future prices cannot be guaranteed.
Astral Resources has positioned itself as one of Australia's more substantive emerging gold developers, with a 2-million-ounce-plus resource base, a PFS-backed project, and a DFS underway. The Theia depth extension drilling — with visible gold logged nearly 400 metres below the current resource — represents one of the more significant near-term catalysts on the ASX for gold investors. With assay results due in June 2026 and a Spargoville resource update to follow in Q3, the next few months are shaping up as a defining period for the company's growth story.
Ready to Dig Deeper Into Astral Resources' Gold Story?
With visible gold logged nearly 400 metres below the current resource boundary, a PFS-backed project boasting a base-case NPV8 of $1.4 billion, and assay results from the Theia depth extension programme due in June 2026, Astral Resources (ASX: AAR) is approaching a pivotal period in its development. Investors seeking to learn more about the Mandilla Gold Project, the expanded diamond drilling programme, and the broader investment case behind one of Australia's more substantive emerging gold developers can find full project details and the latest company news at astralresources.com.au.
