Astral Resources NL
Astral Resources Drills High-Grade Gold at Theia, Advancing Stage 1 Mine Plan Toward Measured Resource Status
Astral Resources drills high-grade gold at Theia Deposit Mandilla Gold Project, releasing a new batch of assay results from its ongoing reverse circulation (RC) in-fill drilling programme at the Theia Deposit, the cornerstone asset of the 100%-owned Mandilla Gold Project near Kalgoorlie, Western Australia. The latest results cover 56 holes for 4,970 metres and continue to validate the geological model underpinning the Stage 1 open pit mine plan, supporting conversion of the Stage 1 inventory to the higher-confidence Measured Mineral Resource classification.
According to the announcement, converting resources to Measured status is a direct prerequisite for advancing the Definitive Feasibility Study (DFS) and progressing project financing discussions. Consequently, each successive batch of in-fill results represents a tangible marker of development progress.
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What the Drill Results Tell Us
The latest assay results are reported to be consistent with, and in many areas above, the grade underpinning the existing Stage 1 Mineral Resource Estimate. The average grade across all intercepts reported in this announcement is 1.24 g/t gold, sitting above the Mineral Resource Estimate (MRE) grade for the Stage 1 pit.
By comparison, the company's two preceding in-fill result announcements averaged 1.93 g/t gold (December 2025) and 1.41 g/t gold (July 2026), reflecting what the company describes as broad consistency of mineralisation across the deposit.
Standout intercepts from this batch include:
| Hole ID | From (m) | Interval (m) | Grade (g/t Au) | Notable High Grade |
|---|---|---|---|---|
| AMRC380 | 12 | 31 | 3.03 | 1m at 59.8 g/t Au from 32m |
| AMRC389 | 41 | 19 | 2.70 | 1m at 36.2 g/t Au from 50m |
| AMRC397 | 106 | 11 | 3.93 | 1m at 34.3 g/t Au from 114m |
| AMRC396 | 74 | 21 | 2.01 | 1m at 14.6 g/t Au from 90m |
| AMRC401 | 71 | 20 | 2.02 | 1m at 22.6 g/t Au from 89m |
| AMRC385 | 39 | 13 | 2.19 | 1m at 12.0 g/t Au from 39m |
| AMRC388 | 12 | 8 | 2.91 | 1m at 19.6 g/t Au from 13m |
| AMRC327 | 17 | 10 | 2.44 | 1m at 19.1 g/t Au from 24m |
| AMRC402 | 61 | 3 | 4.72 | 1m at 13.7 g/t Au from 61m |
| AMRC328 | 87 | 4 | 5.98 | 1m at 15.8 g/t Au from 89m |
According to the announcement, the mineralisation pattern being revealed is characteristic of what Astral's geologists have come to expect at Theia: broad, consistent gold-grade intervals within laterally continuous zones of quartz-sulphide veining that dip shallowly to the southwest.
High-grade shoots sit within this alteration framework, and their location and geometry continue to align with the existing geological and Mineral Resource models, the company reported.
"These results continue to demonstrate the consistency of gold mineralisation within the Stage 1 pit and provide further confidence in both our geological model and the planned conversion of this inventory to the Measured Mineral Resource category. As we anticipated, drilling has continued to delineate broad intercepts of gold mineralisation containing very high-grade shoots within the coherent zones of quartz-sulphide veining, typical of the intense alteration we now know to be ubiquitous with gold mineralisation within the host granite at Theia." — Managing Director Marc Ducler
Understanding Measured Mineral Resources — Why the Classification Upgrade Matters
For investors unfamiliar with resource classification terminology under the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code), the distinction between resource categories helps explain why Astral's in-fill programme is considered strategically significant.
The JORC Code classifies Mineral Resources into three confidence tiers:
- Inferred: Lowest confidence category, based on limited data with assumed geological continuity. Cannot underpin a mine plan or be used to calculate Ore Reserves.
- Indicated: Moderate confidence category, with sufficient data to assume grade and geological continuity. Can support Ore Reserve declarations in many circumstances.
- Measured: Highest confidence category, based on closely-spaced drilling data, typically at 12.5m x 12.5m spacing or tighter. Provides the highest level of certainty for mine planning, feasibility studies, and lender due diligence.
Why Does This Matter for Astral?
The Stage 1 open pit at Theia encompasses 4.2 million tonnes at 1.1 g/t gold for 146,000 ounces of contained gold and covers the first 21 months of the planned mine life, according to the company's Pre-Feasibility Study (PFS). The PFS identified the Stage 1 inventory as the foundation for the early years of cash generation.
Upgrading this inventory from Indicated to Measured is described by the company as a critical milestone that:
- Satisfies the data density requirements for Ore Reserve declarations at the highest confidence level
- Underpins the first 16 months of planned mill feed with increased geological certainty
- Is intended to provide lenders and project financiers with the resource confidence typically required before committing capital
- Advances the DFS toward completion
Furthermore, each hole that validates the existing model at the required drill spacing is presented by the company as bringing the project closer to a mine development decision.
Glossary of Key Terms
| Term | Definition |
|---|---|
| RC Drilling | Reverse Circulation drilling, a method that uses a hammer bit to collect rock chips, which are blown to the surface. Widely used for in-fill resource definition. |
| g/t Au | Grams of gold per tonne of rock, the standard measure of gold grade. Higher values indicate richer ore. |
| MRE | Mineral Resource Estimate, a formal statement of the amount and grade of mineralisation estimated to be present, classified under the JORC Code. |
| JORC Code | The Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves, the industry standard governing how resource estimates are reported in Australia. |
| DFS | Definitive Feasibility Study, the final detailed engineering and economic assessment undertaken before a project investment decision. |
| PFS | Pre-Feasibility Study, a preliminary economic study used to assess project viability before committing to a full DFS. |
| NPV | Net Present Value, a measure of projected future cash flows discounted to present-day terms, and a key metric for assessing project economics. |
| Strip Ratio | The ratio of waste rock to ore that must be removed in an open pit mine. A 4:1 ratio means four tonnes of waste per tonne of ore. |
Drilling Progress and What Comes Next
The in-fill programme at Theia is a three-phase campaign designed to reduce average drill spacing to 12.5m x 12.5m across the entire Stage 1 mining inventory. This is the technical threshold the company has identified as required to support a Measured Mineral Resource declaration.
Programme Status as at Announcement Date
| Programme | Holes Completed | Metres Completed | Total Planned Holes | Total Planned Metres |
|---|---|---|---|---|
| Stage 1 RC In-fill | 151 | 15,131m | 431 | 44,400m |
| Diamond Drilling (Theia Deeps) | 10 | Not specified | 12 | 7,500m |
Key near-term activities outlined in the announcement include:
- RC in-fill drilling of Theia Stage 1 continuing throughout the remainder of CY2026, with a further 280 holes for approximately 29,300 metres planned
- Diamond drilling (DD) at Theia Deeps remains ongoing, with assay results pending for five holes covering 2,614 metres; the expanded 12-hole programme is designed to probe the deeper extent of the mineral system
- Sterilisation drilling at Mandilla to continue pending heritage clearance surveys
- RC and DD drilling planned for the Kamperman Deposit (Feysville) and the Spiders complex (Spargoville) remain on hold pending heritage clearance surveys
Key Upcoming Milestones
Key upcoming milestones cited by the company include:
- Continued Stage 1 in-fill assay batches through CY2026
- Diamond drill assay results from the Theia Deeps programme
- Measured Resource declaration across the Stage 1 inventory, targeted once sufficient drill density is achieved by the end of the CY2026 programme
- DFS completion, forecast for the March Quarter 2027
- An early mining opportunity at Think Big (Feysville), with potential cash flow targeted from the June Quarter 2027
The Mandilla Investment Case in Context
The Mandilla Gold Project sits approximately 70 kilometres south of Kalgoorlie, within the Widgiemooltha Greenstone Belt, an area that hosts established gold operations including Northern Star Resources' Golden Mile Super Pit and Gold Fields' St Ives Gold Mine.
Consolidated Group Resource and Reserve Position
| Project | Category | Tonnes (Mt) | Grade (g/t Au) | Contained Gold (oz) |
|---|---|---|---|---|
| Mandilla | Measured | 1.3 | 1.3 | 57,000 |
| Mandilla | Indicated | 32.6 | 1.0 | 1,092,000 |
| Mandilla | Inferred | 19.6 | 0.9 | 588,000 |
| Mandilla Total | 53.5 | 1.0 | 1,736,000 | |
| Feysville | Indicated + Inferred | 5.0 | 1.2 | 196,000 |
| Spargoville | Indicated + Inferred | 3.0 | 1.4 | 139,000 |
| Group Total | 61.6 | 1.0 | 2,072,000 |
Ore Reserve Position
| Project | Category | Tonnes (Mt) | Grade (g/t Au) | Contained Gold (oz) |
|---|---|---|---|---|
| Mandilla | Probable | 34.3 | 0.9 | 1,000,000 |
| Feysville | Probable | 2.3 | 1.2 | 88,000 |
| Total | 36.6 | 0.9 | 1,082,000 |
The group's total Mineral Resource base stands at 2.07 million ounces of gold, supported by a JORC-compliant Ore Reserve of 1.08 million ounces, according to the company's most recent disclosures.
The Mandilla PFS, released in June 2025, outlined a standalone project comprising seven open pit mines feeding a 2.75 million tonne per annum processing facility, producing an estimated 95,000 ounces per year for the first 12 years. At the base case gold price assumption of $4,250 per ounce, the study reported an NPV (8% discount rate) of $1.4 billion.
At a $6,000 per ounce gold price assumption, the NPV increases to $2.7 billion, according to the PFS.
The Stage 1 pit alone, covering the first 21 months of operation, carries a 4:1 strip ratio, a relatively modest waste-to-ore ratio that the company suggests supports lower initial capital intensity and earlier cash generation potential.
In addition, Mandilla is covered by existing Mining Leases not subject to any third-party royalties beyond the standard Western Australian Government gold royalty, according to the company.
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Why Investors Should Watch Astral Resources
Astral is executing a systematic in-fill and study programme with defined milestones and a DFS timeline aimed at advancing the project toward a development decision. Several characteristics distinguish the company's current position:
- Geological confidence building progressively: Each successive batch of in-fill results has confirmed the deposit model, with grades reported above the MRE benchmark. The current batch, averaging 1.24 g/t gold, reinforces this pattern.
- Near-term catalyst pipeline: The remainder of 2026 is expected to bring continued in-fill assay releases, diamond drill results from Theia Deeps, and progression toward the Measured Resource declaration.
- DFS targeted for March Quarter 2027: This study is intended to define the project's economics and form the basis for project financing discussions, subject to receiving necessary consents and completion of native title heritage surveys.
- Potential early cash flow pathway at Feysville: The Think Big deposit is presented as offering a possible near-term production opportunity, targeted for the June Quarter 2027.
- Scale of the resource base: A 2.07 million ounce group resource within the Widgiemooltha Greenstone Belt, supported by metallurgical test work that the company reports has demonstrated high gold recoveries, fast leach kinetics and low reagent consumption across the main deposits.
"Astral Resources has assembled a gold development portfolio anchored by the Mandilla Gold Project's 2.07 million ounce resource base. With the Theia Stage 1 in-fill programme continuing to validate geology hole-by-hole, a DFS targeted for completion in the March Quarter 2027, and a potential early production opportunity at Feysville, the company has outlined a series of milestones for the remainder of CY2026 against which investors can assess project progress, including further assay results, resource upgrades and study updates."
Want to Learn More About Astral Resources and the Mandilla Gold Project?
With a 2.07 million ounce group resource base, a DFS targeted for the March Quarter 2027, and a systematic in-fill drilling programme delivering consistent high-grade results at the Theia Deposit, Astral Resources (ASX: AAR) is advancing toward a series of defined milestones that investors can track in real time. To explore the full details of the Mandilla Gold Project, the company's development strategy, and its broader Western Australian gold portfolio, visit the official Astral Resources website at astralresources.com.au.
