IRIS Metals Begins Field Exploration at Montana Tungsten Project
IRIS Metals has launched Phase I field activities at its Finley Basin Tungsten Project in Montana, aiming to validate historical mineralisation with a 7,000m drill program scheduled for Q3 2026.
- Phase I exploration underway at Finley Basin, Montana
- Up to 7,000m diamond drilling planned across 16 holes
- Drilling targets historical tungsten mineralisation from Union Carbide era
- Permitting progressing with drill start expected Q3 2026
- Regional exploration expanding tungsten opportunities in western Montana
Field Activities Kick Off at Historically Promising Tungsten Site
IRIS Metals (ASX:IR1) has initiated on-ground exploration at its Finley Basin Tungsten Project in western Montana, marking a pivotal step toward modernising and expanding on historical tungsten discoveries. The company has completed detailed surface sampling, geological mapping, and innovative night traverses using ultraviolet lamps to pinpoint scheelite mineralisation, a tungsten-bearing mineral.
This groundwork has refined drill targeting by confirming key outcrops and access routes, aiming to minimise environmental disturbance ahead of the maiden drilling campaign planned for Q3 2026. The project benefits from established infrastructure and year-round access, factors that bolster its operational readiness.
Drilling Program Designed to Validate and Extend Historical Resource
Pending final permits from state and federal authorities, IRIS Metals is set to commence a Phase I diamond drilling program comprising up to 7,000 metres across 16 drill holes. These will largely twin the 14 holes drilled by Union Carbide in the late 1970s and early 1980s, which defined a non-JORC historical mineral reserve of 850,000 tons at 0.68% WO3.
The drilling aims to verify and expand this mineralisation, focusing on the scheelite-rich Amsden Formation and the garnet-epidote tactite horizon at the base of the Madison Formation, where thicker mineralised zones were previously reported. IRIS has secured drill and helicopter contractors, ensuring readiness for a timely start once permits are granted.
Strategic Positioning in North American Critical Minerals Supply
Finley Basin adds tungsten exposure to IRIS Metals’ North American portfolio, complementing its lithium and rubidium assets in South Dakota. Tungsten is recognised by the US government as a critical mineral, with demand driven by defence, aerospace, energy, and advanced manufacturing sectors. IRIS chairman Chris Evans emphasised the project’s strategic importance amid growing global supply chain security concerns.
Ongoing regional exploration is also underway to assess additional tungsten targets across western Montana, signalling IRIS’s intent to broaden its footprint in this critical mineral space.
Uncertainties Around Historical Estimates and Next Steps
The historical mineral reserve cited is a legacy estimate from Union Carbide, not compliant with modern JORC standards and not independently verified by IRIS. This introduces an element of uncertainty regarding the true scale and grade of the resource. The company’s drilling program is thus critical to upgrading the geological model and potentially defining a JORC-compliant resource.
Key upcoming milestones include permit finalisation and drill mobilisation in Q3 2026, with initial assay results expected by year-end. These developments will be closely watched to gauge the project’s potential and IRIS Metals’ positioning in the tungsten market.
Bottom Line?
IRIS Metals’ transition from historical data to active drilling at Finley Basin could unlock a valuable tungsten resource, but permit approvals and assay results will be decisive in validating the project’s promise.
Questions in the middle?
- Will IRIS Metals’ drilling confirm and expand the historical tungsten mineralisation at Finley Basin?
- How might the evolving US critical minerals policy impact the project’s strategic value?
- What are the prospects for additional tungsten discoveries in western Montana beyond the current project area?
