Tolu Minerals Ltd. has increased the mineral resource estimate at its Tolukuma gold mine in Papua New Guinea by 81% to 909,000 ounces, as the company advances plans to restart production in early 2027.
The updated resource comprises 4.31 million tonnes grading 6.57 grams per tonne (g/t) of gold and 28.2 g/t of silver, containing 909,000 ounces of gold and 3.9 million ounces of silver at a 3 g/t gold cut-off.
The estimate includes a maiden 199,000-ounce Indicated Resource, comprising 850,000 tonnes at 7.33 g/t gold. Tolu said this provides a basis for mine planning and future Ore Reserve estimation.
The resource was independently prepared by H&S Consultants Pty Ltd under the 2012 JORC Code, using data available up to June 30, 2026.
Compared with the previous 2023 estimate at the same cut-off grade, contained gold increased 81%, tonnes rose 169% and contained silver increased 104%.
The average gold grade, however, declined from about 9.6 g/t in the 2023 estimate to 6.57 g/t, which Tolu attributed to the inclusion of a broader volume of mineralised material within the interpreted structural corridor.
Tolu said the increase was driven by 143 drill holes covering 22,975 metres completed between February and June, together with a rebuilt geological model.
The revised model identifies 44 mineralised veins and splays, compared with 15 in the previous interpretation. Only 10 of the 44 are included in the current resource estimate.
The company said the Tolukuma vein system extends for at least 8 kilometres, although only about 1.2 kilometres has been accessed by underground mining. The current resource has an interpreted strike length of about 2.33 kilometres and an average depth of approximately 550 metres below surface.
"Tolu has grown the Tolukuma resource by 81% to 909,000 ounces of gold at 6.6 grams per tonne," Managing Director and Chief Executive Officer Chris Muller said.
He said the company had identified 44 mineralised veins and splays within the mining lease, with only 10 incorporated into the current resource.
Drilling has continued since the June 30 resource cut-off, with seven rigs operating across surface and underground operations. Tolu expects to release a detailed exploration update in October, with results from the post-cut-off drilling expected to contribute to another resource update in 2027.
The company is undertaking a 75,000-metre-plus near-mine drilling campaign focused on the Central Mine Zone and Northern and Southern Expansion Zones.
The campaign is intended to systematically test the Tolukuma system along its known strike and support the planned restart of the mine using existing infrastructure.
Tolu's reported gold resources have now reached 1.037 million ounces, comprising the updated Tolukuma resource and the previously reported 128,000-ounce Inferred Resource at the nearby Saki prospect.
The combined figure represents an increase of 406,000 ounces, or 64%, from the 631,000 ounces previously reported across the two deposits. The two estimates have different effective dates and cut-off grades and have not been aggregated for grade purposes.
Tolu is targeting a return to production at Tolukuma in the first quarter of 2027 using the existing processing plant, hydroelectric station, road access and underground infrastructure.
The company cautioned, however, that it has not yet completed a feasibility study or established an Ore Reserve for Tolukuma.
The proposed restart remains subject to several works, including completion of the Major Infrastructure Project access road and incline, dewatering and exploration drives, underground tailings facilities, mill refurbishment and power upgrades, including the hydroelectric plant and camp expansion.
The Tolukuma mine, located about 100 kilometres north of Port Moresby in Central Province, previously produced about 1 million ounces of gold between 1995 and 2015, at an average recovered grade of about 14 g/t.
Tolu owns the fully permitted mine and about 2,200 square kilometres of surrounding exploration licences.
The company said the updated resource provides a foundation for its proposed production restart, while further drilling is expected to test additional mineralised veins and extensions of the Tolukuma system.
Note: The company's JORC documentation says its recent quality-control programme identified poor-to-medium accuracy and precision in some certified reference materials, including negative bias in a low-grade gold standard and positive bias in a medium-grade standard. No batches were re-assayed based on that performance, and the document says the issue needs to be resolved.
