Costerfield
High-grade underground gold and antimony mine in central Victoria
Producing gold and antimony, a critical mineral
The Costerfield operation lies approximately 10km northeast of Heathcote in central Victoria and 50km east of Bendigo. It is wholly owned by Alkane, following the merger with Mandalay Resources (August 2025).
Underground mining since 2006 has been based variously on the Augusta, Cuffley, Brunswick, Youle and Shepherd deposits within the Costerfield mining district, with production from the 140ktpa Brunswick processing plant (recommissioned 2007).
Currently, Youle and Shepherd are the main source of material for Costerfield. In calendar year 2024, Costerfield produced 43,346 ounces of gold (Au) and 1,282 tonnes of antimony (Sb) – a gold equivalent of 54,805 AuEq ounces.
Key statistics
in 2024
in 2024
Costerfield
of mine until
Growth of resources
A sustained exploration program continues to grow resources for Costerfield’s Brunswick mill. Orebodies remain open at depth, plus we have additional near-mine targets in the district.
The Inferred Resource for the True Blue deposit, approximately 2km northwest of the current Youle workings, increased by more than 300% in 2024.
The combined Costerfield Mineral Resources at 31 December 2024 stood at 450koz contained gold and 39.9kt contained antimony.
Project news
Resources and reserves
At 31 December 2024, Mineral Resources and Ore Reserves for Costerfield stood at:
- Total Mineral Resources (Measured and Indicated): 1.197Mt at 8.3g/t gold (320koz) and 2.5% antimony (30.2kt)
- Total Mineral Resources (Inferred): 538kt at 7.5g/t gold (130koz) and 1.8% antimony (9.7kt)
- Total Ore Reserves (Proven + Probable): 604kt at 8.7g/t gold (168koz) and 1.8% antimony (11.1kt)
These are based on the Augusta, Cuffley, Brunswick, Youle and Shepherd deposits (Costerfield) and the True Blue deposit.
Mineral resources as at 31 December 2024 (click to expand)
| Category | Inventory (kt) | Gold Grade (g/t) | Antimony Grade (%) | Contained Gold (koz) | Contained Antimony (kt) |
| Measured (Underground) | 412 | 13.6 | 3.6 | 180 | 14.8 |
| Measured (Stockpile) | 43 | 5.7 | 0.8 | 8 | 0.3 |
| Indicated | 741 | 5.5 | 2.0 | 132 | 15.0 |
| Measured + Indicated Total | 1,197 | 8.3 | 2.5 | 320 | 30.2 |
| Inferred (Costerfield) | 392 | 5.5 | 1.3 | 69 | 5.2 |
| Inferred (True Blue) | 145 | 13.1 | 3.1 | 61 | 4.5 |
| Inferred Total | 538 | 7.5 | 1.8 | 130 | 9.7 |
Ore reserves as at 31 December 2024 (click to expand)
| Category | Tonnes (kt) | Gold Grade (g/t) | Antimony Grade (%) | Contained Gold (koz) | Contained Antimony (kt) |
| Proven Underground | 307 | 11.43 | 2.1 | 113 | 6.5 |
| Proven Stockpile | 43 | 5.7 | 0.8 | 8 | 0.3 |
| Probable | 253 | 5.9 | 1.69 | 48 | 4.3 |
| Proven + Probable | 604 | 8.7 | 1.8 | 168 | 11.1 |
Environment & social
We are committed to operational best practice for the environment, the safety and wellbeing of our employees and the resilience of our host communities and traditional custodians around Costerfield.
Environment, safety and communities remain key pillars of our day-to-day decisions and actions. All our operations are conducted under valid licences, permits and management plans. Costerfield maintains an endorsed Community Engagement Plan.
Careers
Costerfield offers rewarding career opportunities for university graduates, people qualified through the vocational education and training (VET) system, apprentices in some trades and operators with experience in heavy machinery.
Some entry-level operator positions have limited skills requirements, and we encourage members of the local community to apply for on-the-job training. We value employees from a diverse range of backgrounds and are committed to equal-opportunity recruitment.
We are a “residential” operation, meaning all employees return to their own homes at the end of each shift. The site is near the major regional centre of Bendigo.
Timeline
