MGX Resources has reported its first Central Tanami resource statement since acquiring a 50% stake, giving the company an attributable 1.4 million ounces of gold. The shift comes as Koolan Island’s remaining iron ore resources fall to 3.3 million tonnes and its Ore Reserves are reduced to zero ahead of a planned divestment.
- 31.0Mt at 2.8g/t gold for 2.8Moz across Central Tanami on a 100% basis
- MGX’s 50% share amounts to 1.4Moz of contained gold
- Koolan Island retains 3.3Mt at 59.3% Fe, all at the undeveloped Mangrove deposit
- No Koolan Island Ore Reserves remain after the Main Pit rockfall and stockpile depletion
- Central Tanami development decision and further drilling remain key milestones
Central Tanami becomes MGX’s defining resource base
MGX Resources Limited (ASX:MGX) now has a 1.4 million ounce attributable gold resource at the Central Tanami Project, a substantial change in the shape of the company’s mineral inventory after its February acquisition of a 50% joint venture interest. The project’s total Mineral Resource stands at 31.0 million tonnes grading 2.8 grams per tonne gold for 2.8 million ounces on a 100% basis.
The largest single component is Groundrush and Ripcord, which together contain 13.0Mt at 3.2g/t gold for 1.3Moz. Groundrush accounts for 11.0Mt at 3.3g/t gold for 1.2Moz, with the resource reported across open-pit and underground material. The resource statement arrives after the Groundrush decline contract was awarded in August for underground access and infill drilling.
Development case remains ahead of the resource statement
MGX and joint venture partner Tanami Gold NL are working towards a development decision, but the announcement does not convert the Central Tanami Mineral Resources into Ore Reserves. The estimates were constrained using pit shells and underground stope optimisation based on a gold price assumption of A$3,500 per ounce, while the project’s existing 1.2 million tonne per annum carbon-in-leach plant has been idle since 2005.
There are also important qualifications beneath the headline ounces. Results from all drilling completed during the 2025 field season, as well as the 2026 field season, were not included for Jims and Groundrush. Some Central Tanami deposits rely on limited or assumed metallurgical data, and fresh rock at several deposits may require a flotation and concentrate circuit rather than conventional processing alone. The company says the outstanding drilling results are intended to feed future resource updates.
Koolan Island’s remaining inventory is no longer an operating reserve
The iron ore side of the ledger tells a much less expansive story. Koolan Island’s remaining Mineral Resources total 3.3Mt grading 59.3% iron, all within the undeveloped Mangrove satellite deposit. No Ore Reserves remain, compared with 4.1Mt at 65.0% iron a year earlier.
The change reflects the October 2025 Main Pit rockfall, which ended mining there after geotechnical reviews determined it could not safely resume, followed by the depletion of available low-grade stockpiles. MGX completed sales of that material in July 2026, having sold 2.1Mt in total since the stockpile program began. The company expects no iron ore Mineral Resources to remain once its Koolan Island sale agreement with Crestlink Koolan settles, targeted for late 2026 or, if extended, by the end of March 2027.
The next test is execution, not geological scale
For MGX, the filing marks a clean strategic handover from a depleted iron ore operation to a gold project with significant historical infrastructure, an existing mill and a large resource footprint. The company completed its Central Tanami acquisition in February for A$50 million, but the resource itself remains a starting point for development work rather than a production schedule.
The unresolved questions are practical: how much refurbishment and new processing capacity Central Tanami will require, whether further drilling can upgrade the substantial Inferred component, and whether metallurgical assumptions hold across the project’s varied deposits. Until those points are answered, MGX’s 1.4Moz attributable figure is an important inventory marker, but not yet a measure of mineable output.
Bottom Line?
MGX has replaced Koolan Island’s shrinking reserve base with a sizeable attributable gold resource, but the investment case now turns on development studies, metallurgy, funding and conversion of resources into reserves.
Questions in the middle?
- How much of the 1.4Moz attributable Central Tanami resource can be converted into Ore Reserves after further drilling and technical work?
- What capital and processing changes will be required to restart or refurbish the idle Central Tanami plant?
- Will the Koolan Island divestment settle on schedule, and what obligations will remain with MGX if it is extended?