The Mt Gibson Gold Project (“MGGP”) is located in the Mid-West region of Western Australia, approximately 280 kilometres north-east of Perth. Capricorn acquired the project in July 2021 and has since undertaken extensive drilling, growing the reserve base to 2.6 million ounces.
In November 2024, the Company released an update to the April 2023 pre-feasibility study, confirming MGGP as a transformative, fully funded second mine for the Company. Based on reserves alone, the operation has a projected mine life of 17 years, including two final years of low-grade processing, with annual production of 150,000 ounces. The April 2023 development cost estimate of $260 million for the plant, together with pre-production mining capital of $83 million, remains appropriate.
In July 2025, an updated Mineral Resource Estimate (“MRE”) included a maiden underground resource of 6.84Mt at 3.1g/t Au for 684,000 ounces of gold, reinforcing the Company’s view that MGGP will evolve into a long-life operation combining open pit and underground mining.
The permitting process is well advanced. In June 2025, Capricorn submitted the final Public Environmental Report (“PER”) to the Department of Climate Change, Energy, the Environment and Water (DCCEEW), commencing the public exposure and final assessment process.
Mt Gibson Mineral Resources and Ore Reserves
JORC-2012 compliant MINERAL RESOURCE ESTIMATE as at 22 JULY 2025.
On 22 July 2025, Capricorn announced an update to the MRE at the MGGP. The updated MRE is 149.2 million tonnes at 0.9g/t Au for 4,498,000 ounces of gold as shown below:
| Indicated | Inferred | Total Mineral Resources | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Deposit | Type | Cut-off (g/t) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
| Laterite | Open-Pit | 0.4 | 0.8 | 0.6 | 14 | 1.3 | 0.6 | 23 | 2.1 | 0.6 | 38 |
| Oxide | Open-Pit | 0.4 | 10.7 | 0.8 | 285 | 0.3 | 0.7 | 7 | 11.0 | 0.8 | 292 |
| Transitional | Open-Pit | 0.4 | 13.3 | 0.8 | 342 | 0.6 | 0.7 | 13 | 13.9 | 0.8 | 355 |
| Fresh | Open-Pit | 0.4 | 86.7 | 0.9 | 2,508 | 20.8 | 0.7 | 455 | 107.5 | 0.9 | 2,963 |
| HLP | Open-Pit | 0.3 | 3.7 | 0.4 | 52 | 0.3 | 0.4 | 4 | 4.0 | 0.4 | 56 |
| Highway | Open-Pit | 0.5 | 3.0 | 0.9 | 89 | 0.9 | 0.7 | 21 | 3.9 | 0.9 | 110 |
| Orion South UG | Underground | 1.5 | – | – | – | 6.8 | 3.1 | 684 | 6.8 | 3.1 | 684 |
| Total | 118.1 | 0.9 | 3,290 | 31.1 | 1.2 | 1,208 | 149.2 | 0.9 | 4,498 | ||
Notes on the Mineral Resource estimate:
- OP Mineral Resources are estimated using a gold price of A$2,400/ounce.
- OP Mineral Resources are estimated using a cut-off grade between 0.3g/t and 0.5g/t Au, UG 1.5g/t Au.
- The above data has been rounded to the nearest 100,000 tonnes, 0.1 g/t gold grade and 1,000 ounces. Errors of summation may occur due to rounding.
JORC-2012 compliant ORE RESERVE estimate as at 30 JUNE 2025
On 6 October 2025, Capricorn announced an update to the ORE at the MGGP. The updated ORE is 95.0 million tonnes at 0.9g/t Au for 2,736,000 ounces of gold as shown below:
| Proved | Probable | Total Ore Reserves | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Deposit | Type | Cut-off (g/t) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
Tonnes (Mt) |
Grade (g/t) |
Metal (koz) |
| Laterite | Open-Pit | 0.4 | – | – | – | 0.9 | 0.5 | 15 | 0.9 | 0.5 | 15 |
| Oxide | Open-Pit | 0.4 | – | – | – | 10.3 | 0.9 | 284 | 10.3 | 0.9 | 284 |
| Transitional | Open-Pit | 0.4 | – | – | – | 11.6 | 0.8 | 311 | 11.6 | 0.8 | 311 |
| Fresh | Open-Pit | 0.4 | – | – | – | 68.9 | 0.9 | 2,076 | 68.9 | 0.9 | 2,076 |
| HLP | Open-Pit | 0.3 | – | – | – | 3.5 | 0.4 | 50 | 3.5 | 0.4 | 50 |
| Stockpiles | Stockpiles | 0.4 | – | – | – | – | – | – | – | – | – |
| Total | – | – | – | 95 | 0.9 | 2,736 | 95 | 0.9 | 2,736 | ||
Notes on the Ore Reserve estimate:
- Ore Reserves are a subset of Mineral Resources.
- Ore Reserves are estimated using a gold price of A$2,200/ounce.
- Ore Reserves are estimated using a cut-off grade over 0.4g/t Au, except Heap Leach Pad material using a cut-off grade over 0.3g/t.
- The above data has been rounded to the nearest 100,000 tonnes, 0.1 g/t gold grade and 1,000 ounces. Errors of summation may occur due to rounding.