Astral Resources Doubles Spargoville Gold to 281koz Resource
Key Takeaways
- Astral Resources lifted its Spargoville resource 102% to 8.5Mt at 1.0g/t Au for 281koz, with Indicated ounces up 130% to 186koz.
- The jump is mainly driven by a higher gold price assumption of A$4,500/oz versus A$3,500/oz, with only 16,000m of new RC drilling behind it.
- The group resource now totals 2.21Moz, but the figure blends A$2,500, A$3,500 and A$4,500/oz constraints, so the ounces are not like-for-like.
- Drilling has restarted at Spiders, the largest deposit at 177koz, which remains open at depth.
- The Mandilla DFS, using the same cost parameters, is the next milestone, and the company says Spargoville plus Mandilla can support stand-alone processing infrastructure.
Spargoville Gold Project Mineral Resource Estimate jumps 102% to 281koz
Astral Resources (ASX: AAR) has lifted the Mineral Resource Estimate (MRE) for its 100%-owned Spargoville Gold Project by 102% to 8.5Mt at 1.0g/t Au for 281koz of contained gold, reported under the JORC Code (2012 Edition). The project sits 70km south of Kalgoorlie in Western Australia.
A Mineral Resource Estimate is a formal calculation of how much gold a deposit holds, and the previous Spargoville figure was 3.0Mt at 1.4g/t Au for 139koz. Indicated Resources, the higher-confidence category, rose 130% to 5.1Mt at 1.1g/t Au for 186koz.
The consolidated Group MRE now stands at 67Mt at 1.0g/t Au for 2.21Moz. The growth came with only 16,000m of new Reverse Circulation (RC) drilling, which suggests the larger number owes more to re-estimation than to heavy drilling.
Key highlights from the update:
- Spargoville MRE up 102% to 281koz of contained gold
- Indicated Resources up 130% to 186koz
- Spiders, Eagles Nest, 8500N and 5B re-estimated at a 0.40g/t Au lower cut-off within A$4,500/oz pit shells
- Group MRE (Mandilla, Feysville and Spargoville) now 2.21Moz
Marc Ducler, Managing Director
“The result is a pleasing 102% increase in the contained gold, which we believe is a strong validation of the future growth potential of these assets. Part of the motivation for completing this re-optimisation was to help us refine upcoming drilling programs to target further growth.”
When big ASX news breaks, our subscribers know first
What drove the increase in the Spargoville MRE?
Re-optimised at A$4,500/oz
The Spiders deposit (which combines Redback, Huntsman, Trapdoor, Golden Orb and S5), Eagles Nest, 8500N and 5B were re-estimated at a 0.40g/t Au lower cut-off. A lower cut-off is the minimum grade included in the estimate. The deposits were constrained within pit shells derived using a gold price of A$4,500 per ounce.
The cost assumptions match those used for the upcoming Mandilla Gold Project Definitive Feasibility Study (DFS) mine optimisations. Independent consultant Cube Consulting prepared the estimates.
Wattle Dam Stockwork, Hilditch and Larkinville are unchanged from the May 2025 MRE.
The source attributes the major variance to the gold price rising from A$3,500 to A$4,500 per ounce, which produced larger optimised pit shells. Minor decreases came from reinterpretation and estimation, and from the cut-off rising from 0.39g/t Au to 0.40g/t Au.
Deposit breakdown
Spiders is the largest accumulation, with 5.5Mt at 1.0g/t Au for 177koz. The table below reproduces the Total classification for each deposit from the source.
| Deposit | Classification | Tonnes (Mt) | Grade (g/t Au) | Au Metal (oz) |
|---|---|---|---|---|
| Wattle Dam Stockwork* | Total | 0.3 | 1.4 | 15,000 |
| Spiders | Total | 5.5 | 1.0 | 177,000 |
| 8500N | Total | 1.0 | 0.8 | 26,000 |
| Eagles Nest | Total | 0.8 | 1.1 | 30,000 |
| Larkinville* | Total | 0.2 | 1.7 | 12,000 |
| Hilditch* | Total | 0.4 | 1.3 | 15,000 |
| 5B | Total | 0.2 | 1.3 | 7,000 |
| Total | Total | 8.5 | 1.0 | 281,000 |
*Unchanged from the May 2025 MRE update. Minor discrepancies may occur due to rounding.
Understanding Mineral Resource estimates and why pit shells matter
A Mineral Resource is a concentration of gold that has reasonable prospects for eventual economic extraction. It is not an Ore Reserve, which is a separate, more advanced category. Ore Reserves are a subset of Mineral Resources, and Astral’s current Ore Reserves are Mandilla at 1.0Moz and Feysville at 88koz, estimated at A$3,000 per ounce.
Resources are split by confidence. Indicated material is better defined by drilling, while Inferred material sits within the mineralised domain but does not meet the Indicated criteria. At Spargoville, no material has been classified as Measured, and the Indicated Resource has a nominal drill spacing of 20m x 20m or closer.
The pit shell is the test of “reasonable prospects for eventual economic extraction”. It is a modelled open pit outline showing which material could be mined at a given gold price and cost. Ducler described the A$4,500/oz assumption as “conservative”, saying it “shows that the financial metrics that underpin the Resource are very robust.” Using costs consistent with the Mandilla DFS means the numbers share a common basis with that study.
Key assumptions behind the optimisations:
- Overall processing recovery of 96%
- Processing plus G&A cost of $30/t
- Average mining costs of $5.03-$5.68/t, depending on the deposit
Metallurgical testing showed gold recoveries of 91.5% to 97.3% at Wattle Dam and 86% to 94% at Eagles Nest. The source describes these as preliminary results and recommends more testing across all four deposits to increase confidence.
The next major ASX story will hit our subscribers first
Investment thesis and next steps
Consolidated Group MRE
The Group MRE combines three projects. The table shows Total Mineral Resource figures only, as the source’s two consolidated tables show different Indicated and Inferred splits for Mandilla.
| Project | Total tonnes (Mt) | Total grade (g/t Au) | Total metal (oz Au) |
|---|---|---|---|
| Mandilla | 53.5 | 1.0 | 1,736,000 |
| Feysville | 5.0 | 1.2 | 196,000 |
| Spargoville | 8.5 | 1.0 | 281,000 |
| Total | 67.0 | 1.0 | 2,214,000 |
The ounces are not like-for-like. Feysville is constrained at A$2,500 per ounce and the remainder of Spargoville at A$3,500, while Mandilla and the re-estimated Spargoville deposits use A$4,500.
Drilling restarts
Astral is back drilling at Spiders in the current December Quarter. Ducler said part of the motivation for the re-optimisation was to help refine upcoming drilling programs to target further growth.
Mineralisation remains open at depth at Spiders, with significant intercepts in holes RBDD008 and RBDD008W1 requiring further investigation. At Eagles Nest, it remains open to the south and at depth.
The source states the project, when combined with Mandilla, is of sufficient scale to support stand-alone processing infrastructure. It is located on granted mining leases, and heritage surveys are ongoing.
For investors, the next items to watch are the Mandilla DFS, which will use the same parameters, and results from the renewed Spiders drilling.
Ready To Learn More About The Spargoville Gold Project?
Astral Resources has doubled the Spargoville Mineral Resource Estimate by 102% to 281koz, lifting its Group Resource to 2.21Moz. With drilling restarting at Spiders and the Mandilla DFS on the horizon, the next catalysts are close.
Explore the full picture on the Astral Resources company page at Discovery Alert to see how these projects could shape its growth story.