Mantle Minerals finds a new structural angle at Carlton Hill

Carlton Hill exploration model moves deeper

Mantle Minerals Limited (ASX:MTL) is resetting its Carlton Hill exploration strategy after a desktop review suggested the project may be controlled more by geological structures than the shallow, stratiform model used to guide earlier work. The shift puts greater emphasis on locating prospective structures that could host zinc-lead and copper mineralisation.

The change is still an exploration interpretation, not a discovery announcement. Mantle has engaged Core Geophysics to reinterpret its existing geophysical, geological, geochemical and drilling data, generate and rank target areas, and recommend further surveys. Induced polarisation is among the techniques that may be considered before the company decides whether the targets justify drilling.

“Carlton Hill Project Location Map”

The work builds on Mantle's earlier Carlton Hill tenement expansion, which included the grant of E80/6170 and the planned acquisition of the adjoining E80/6134 application. Carlton Hill lies about 50 kilometres north of Kununurra along the Carlton Shelf structural trend, roughly 35 kilometres west of Boab Metals' Sorby Hills lead-zinc-silver deposit. Mantle cautions that Sorby Hills is on separate tenure and is not necessarily indicative of Carlton Hill's mineralisation potential.

Drilling remains conditional on targets and approvals

Mantle says it will assess the ranked targets once the technical review is complete. If drill targets emerge, the company intends to progress heritage, land access, native title and regulatory approvals before any potential drilling campaign. That leaves several gates between the revised model and work in the field.

“Yule River Project Location Map”

At Yule River, about 35 kilometres west of Port Hedland, the Program of Work has been approved, but native title negotiations remain ongoing. The project hosts a group of geophysical targets identified through gravity, passive seismic and historical aeromagnetic surveys, with possible relevance to VHMS, orogenic gold and magmatic nickel-copper-PGE mineralisation. Mantle's near-term focus is technical work at Carlton Hill and resolving access issues at Yule River, while further field activity will depend on those processes.

Cash provides time, but exploration spending is limited

The quarterly cash flow report showed A$5.232 million in cash at 30 September, down from A$5.498 million at the end of the previous quarter. Net operating cash outflow was A$166,000 and investing cash outflow was A$100,000, with no financing inflow recorded. On the quarter's reported relevant outgoings, Mantle calculated 31.59 quarters of estimated funding available, a measure that would change if exploration activity accelerates.

Exploration cash outflows were A$17,085 at Yule River, A$23,345 at Pardoo and A$4,309 at Carlton Hill. The modest Carlton Hill spend is consistent with a quarter centred on reinterpretation rather than drilling, but the next stage could require materially different expenditure if geophysics produces targets worth testing.

Corporate changes follow capital return ruling

After quarter end, the Australian Taxation Office published Class Ruling CR 2026/81, confirming that no part of Mantle's return of capital was a dividend for Australian income-tax purposes for eligible shareholders who held shares on capital account at the relevant record date. The ruling follows the company's earlier ATO capital return ruling, which reported that the A$0.001 per share payment made in November 2025 was not dividend or ordinary income.

Monty Purich became company secretary in September, replacing Kieran Witt, and was appointed a non-executive director after Robert Mosig resigned at the conclusion of the 28 October annual general meeting. Purich continues in both roles. With Carlton Hill still at the target-generation stage, the key test for the new exploration model will be whether Core Geophysics can convert a conceptual structural interpretation into targets that survive technical review, approvals and the cost of drilling.