Tolu Minerals Grows Gold Resource 81% to 909koz Targeting Q1 2027 Restart
Key Takeaways
- The Tolukuma Mineral Resource Estimate has grown 81% to 909,000 oz of gold (4.31 Mt at 6.57 g/t Au) after 143 holes drilled between February and June 2026, with contained silver also rising 104% to 3.9 Moz.
- Combined with the Saki Inferred Resource of 128 koz, Tolu Minerals now holds over 1,037,000 oz of total reported gold resources across two Papua New Guinea deposits — a 64% increase on previously reported figures.
- A maiden Indicated Resource of 199 koz (0.85 Mt at 7.33 g/t Au) has been established for the first time, a critical step toward Ore Reserve estimation and formal mine planning.
- Only 10 of 44 identified mineralised veins and splays are included in the current resource, and seven rigs continue drilling post the 30 June 2026 data cut-off, with an exploration update expected in October 2026.
- The company is targeting a return to gold production at Tolukuma in Q1 2027 using existing, fully permitted infrastructure, though no feasibility study or Ore Reserve has yet been completed.
Tolukuma resource grows 81% to 909,000 oz gold as Tolu crosses the 1 million ounce milestone
Tolu Minerals (ASX: TOK) has delivered a landmark resource update for its Tolukuma Gold Mine in Papua New Guinea, with the Mineral Resource Estimate growing 81% to 909,000 oz of gold (4.31 Mt at 6.57 g/t Au) and 3.9 Moz of silver, after just four months of full run-rate drilling between February and June 2026. Combined with the previously reported Saki Inferred Resource of 128 koz, Tolu’s total reported gold resources now exceed 1 Moz, reaching 1,037,000 oz — an increase of 406,000 oz, or 64%, on previously reported figures across the two deposits.
The update also establishes a maiden Indicated Resource of 199 koz (0.85 Mt at 7.33 g/t Au), a significant step toward mine planning and Ore Reserve estimation. The company’s plan is to return Tolukuma to gold production in Q1 2027, using existing, fully permitted infrastructure.
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What drove the 81% uplift — new drilling and a rebuilt geological model
Two factors drove the resource growth: a substantial new drilling programme and a complete rebuild of the geological model.
Between February and June 2026, the company completed 143 holes for 22,975 m to the 30 June 2026 data cut-off. That programme delivered two new high-grade near-mine discoveries: the Fundoot Splay (4.67 m at 42.76 g/t Au, including 1.3 m at 82.8 g/t Au) and the Gulbadi Splay (2 m at 16.94 g/t Au). Drilling also confirmed the continuity of mineralisation at the Gufinis and Zine lodes, and infilled principal lodes to the spacing required to support the maiden Indicated Resource.
The Fundoot and Gulbadi vein discoveries represent the most visible proof that the revised geological model is generating predictive targets, with high-grade intercepts in both splays confirming structural zones well beyond the historically mined portions of the system.
The geological model rebuild is the other major contributor. The revised model now recognises 44 mineralised veins and splays, compared with just 15 previously, reflecting the understanding that gold at Tolukuma is hosted in structural zones containing multiple quartz-adularia veins, disseminated sulphides, and clay-fault zones rather than a single narrow vein.
The average gold grade reduced from approximately 9.6 g/t to 6.57 g/t. This reflects the new model capturing the full width of mineralised structural zones rather than a single narrow vein — the increase in contained metal is what matters here, not the diluted average grade. The estimate was prepared independently by H&S Consultants Pty Ltd (HSC) in accordance with the 2012 JORC Code, with a data cut-off of 30 June 2026.
Resource growth vs. 2023 estimate (3 g/t Au cut-off):
- Tonnes: +169%
- Contained gold ounces: +81%
- Contained silver ounces: +104%
The updated MRE by classification is set out below:
| Classification | Tonnes (Mt) | Au (g/t) | Ag (g/t) | Gold (koz) | AuEq (koz)¹ |
|---|---|---|---|---|---|
| Indicated | 0.85 | 7.33 | 33.0 | 199.1 | 210.7 |
| Inferred | 3.46 | 6.38 | 27.1 | 710.1 | 749.0 |
| Total | 4.31 | 6.57 | 28.2 | 909.2 | 959.7 |
¹ AuEq is supplementary information only, calculated using US$3,500/oz gold, US$45/oz silver, and assumed recoveries of 80% for both metals. AuEq should not be interpreted as a separate Mineral Resource Estimate.
Understanding mineral resource estimates — why this update matters for investors
What is a JORC mineral resource?
A Mineral Resource Estimate (MRE) is an independent assessment of the quantity and grade of mineralisation that has reasonable prospects for eventual economic extraction, reported under the JORC Code (the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves). Resources are classified by confidence level: Indicated resources carry higher confidence, supported by closer-spaced drilling and better data quality, which means they can underpin mine planning and Ore Reserve estimation. Inferred resources carry lower confidence and cannot be used to support Ore Reserves.
The maiden 199 koz Indicated Resource at Tolukuma is therefore a meaningful step forward. It signals that a portion of the deposit is now understood well enough to begin informing the mine plan — not just the exploration story.
The AuEq figure of approximately 960 koz is supplementary information only. It expresses the silver content in gold terms using price and recovery assumptions, and does not represent a separate resource.
Why grade matters less than contained ounces at this stage
The grade reduction from approximately 9.6 g/t to 6.57 g/t is not a sign of lower-quality ore. Tonnage grew 169% as the model captured the full width of mineralised structural zones, pushing contained gold up 81%. More material at a slightly lower average grade equals significantly more gold in the ground.
For context, 6.57 g/t remains high-grade by global underground gold mine standards. The question at this stage of resource development is whether there is enough metal to support a mine — and the answer has grown substantially more positive.
Only the beginning — 44 veins identified, just ten in the current resource
The Tolukuma vein system extends for at least 8 km of strike, of which only approximately 1.2 km has ever been accessed by underground mining. The revised geological model recognises 44 mineralised veins and splays, yet only ten are included in the current MRE. A substantial proportion of drilling intersections completed to date have not yet contributed a single ounce to the resource.
The 75,000 m+ near-mine drilling campaign is systematically testing the system across three directions:
- Central Mine Zone — around existing underground infrastructure
- Northern Expansion Zone — reachable by short development drives from existing workings
- Southern Expansion Zone — also accessible from existing workings
Drilling has not stopped since the 30 June 2026 data cut-off. Seven rigs are operating from surface and underground, and a detailed exploration update with post-cut-off results is expected during October 2026. Those results will feed into the next MRE update, planned for 2027.
An additional near-mine growth opportunity exists in the Saki-Yava gold system, with a previously reported Inferred Resource of 2.0 Mt at 2.0 g/t Au for 128 koz, reported at a 1 g/t Au cut-off. Saki has not been re-estimated as part of the current update, and its cut-off grade differs from Tolukuma’s — the two deposit grades should not be aggregated.
Dr Chris Muller, Managing Director and CEO, Tolu Minerals
“This is a step change for Tolu. In only four months of full run-rate drilling we have grown the Tolukuma resource by 81% to 909,000 ounces of gold at 6.6 grams per tonne, and for the first time the market can see the full shape of the opportunity: a rebuilt geological model that is proving predictive, and a mining lease where only 1.2 kilometres of an 8 kilometre system has ever been mined.
Just as important is what this estimate does not yet include. Our revised interpretation recognises 44 mineralised veins and splays within the Mining Lease alone, with just ten in the current Mineral Resource, and our rigs have not stopped since the 30 June cut-off. We have drilled substantial metres since then, we have a series of excellent results in hand, and we look forward to updating the market in October. Those results, and the 75,000 metre campaign that follows, will feed the next resource update in 2027.
The updated estimate gives us a much stronger foundation as we bring Tolukuma back into production early next year. With the previously reported Saki resource nearby, Tolu now has more than one million ounces of reported gold resources in Papua New Guinea, and we believe we are only beginning to demonstrate the scale of this system.”
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Foundation set for Tolukuma’s return to gold production in early 2027
The updated MRE is consistent with, and provides the foundation for, the company’s plan to return Tolukuma to gold production in Q1 2027, using the existing processing plant, hydro-electric station, road access, and underground infrastructure. The Northern and Southern Expansion Zones and the untapped veins around existing infrastructure are expected to provide the mining fronts to sustain and grow production.
Several items remain outstanding before restart. The production restart and subsequent ramp-up are subject to completion of:
- The Major Infrastructure Project access road and incline
- Dewatering exploration drives
- Underground tailings facilities
- Mill refurbishment and power upgrades (including hydro plant and camp expansion)
It is important to note that the company has not yet completed a feasibility study, and no Ore Reserve has been established for Tolukuma. The company expects to provide further detail on the mine plan and production schedule in the coming months.
For historical context, Tolukuma produced approximately 1 Moz of gold at an average recovered grade of approximately 14 g/t between 1995 and 2015. The updated resource base now provides a substantially larger foundation from which the company is seeking to restart that production history.
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