Tolu Minerals has increased the Tolukuma gold resource by 81% to 909,000 ounces after four months of full-scale drilling, pushing its reported Papua New Guinea gold inventory above one million ounces. The proposed early 2027 restart now has a larger resource base, but remains dependent on infrastructure, technical work and conversion of resources into mineable reserves.
- Tolukuma resource rises 81% to 909 koz of gold
- Maiden Indicated Resource contributes 199 koz at 7.33 g/t Au
- Tolu’s reported gold resources reach 1.037 Moz including Saki
- 75,000-metre near-mine drilling campaign continues
- Q1 2027 restart remains subject to infrastructure and technical requirements
Tolu Minerals Limited (ASX:TOK) has added 406,000 ounces to its reported gold inventory, lifting the Tolukuma Mineral Resource Estimate by 81% to 909,200 ounces. The updated estimate also includes a maiden 199,100-ounce Indicated Resource, giving the company a firmer geological base as it works towards a planned return to production in the first quarter of 2027.
The resource contains 4.31 million tonnes at 6.57 grams per tonne gold and 28.2 grams per tonne silver, reported at a 3 g/t gold cut-off and after depletion for historical mining. Tolu’s reported gold resources now total 1.037 million ounces when the previously reported, entirely Inferred, 128,000-ounce Saki resource is included. Saki was not re-estimated in this update, and the two resources use different cut-off grades and effective dates.
Drilling and Geological Model Drive Resource Growth
The uplift came from 143 holes covering 22,975 metres drilled between February and June 2026, combined with a complete rebuild of the Tolukuma geological model. Two new high-grade discoveries were incorporated into that work: the Fundoot Splay returned 4.67 metres at 42.76 g/t gold, including 1.3 metres at 82.8 g/t, while the Gulbadi Splay returned 2 metres at 16.94 g/t.
H&S Consultants’ independent model recognises 44 mineralised veins and splays, compared with 15 in the previous interpretation, although only ten are included in the current resource. The revised estimate is therefore larger but lower grade than the 2023 version: tonnes rose 169%, contained gold increased 81% and silver grew 104%, while average gold grade fell from about 9.6 g/t to 6.57 g/t. That change reflects the inclusion of wider structural zones rather than only narrow, higher-grade vein structures.
More Drilling Before the Next Resource Update
Seven rigs have continued drilling since the 30 June data cut-off, meaning the latest results are absent from the new estimate. Tolu expects to publish a detailed drilling update in October, with those results feeding into another resource update planned for 2027. The company says the broader vein system extends for at least 8 kilometres, of which only about 1.2 kilometres has been accessed by underground mining.
The immediate investment tension is that the resource milestone is not yet a mine plan. Tolukuma has no completed feasibility study or Ore Reserve, and the restart remains subject to completion of the access road and incline, dewatering drives, underground tailings facilities, mill refurbishment, power upgrades and camp expansion. The company also flags local uncertainty from variable drill spacing, limited density data, poor core recovery in some holes and weaknesses in parts of the assay quality-control record, including accuracy and precision issues in certain reference materials.
Restart Target Still Depends on Mine Development
Tolu intends to use the existing processing plant, hydro-electric station, road access and underground infrastructure, with the Central Mine Zone and Northern and Southern Expansion Zones forming the focus of the 75,000-metre-plus near-mine campaign. The updated resource improves the scale of the opportunity, but the next test is whether enough of those ounces can be converted into an Ore Reserve and supported by a credible production schedule before the targeted Q1 2027 restart.
Bottom Line?
The resource has moved Tolukuma into a larger league on paper; the decisive milestones now are Ore Reserve conversion, mine development and evidence that the restart timetable can withstand technical and funding demands.
Questions in the middle?
- How much of the 909 koz resource can ultimately be converted into an Ore Reserve?
- Will the October drilling results materially expand the resource beyond the ten lodes currently modelled?
- Can the required access, dewatering, tailings, mill and power works be completed in time for the Q1 2027 restart?