Red Mountain Mining Ltd
Red Mountain Mining Strikes Outcropping Tungsten Skarn at Pioneer Project — Magnetic Modelling Points to Significant Subsurface Potential
Red Mountain Mining (ASX: RMX) has made a meaningful early-stage discovery at its 100% owned Pioneer Tungsten Project in Montana, USA, confirming outcropping garnet skarn at two of its three prospect areas and identifying compelling subsurface magnetic signatures that suggest the tungsten-bearing mineralisation system extends to drillable depths. The Red Mountain Mining Pioneer Tungsten Project tungsten discovery in Montana is particularly significant, with 24 rock chip samples already dispatched for analysis and results expected before the end of June. The company is now positioning itself to move rapidly toward drill testing — potentially within the current northern hemisphere summer.
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What Has Been Found, and Why Does It Matter?
During a three-day reconnaissance field visit in late May, Red Mountain's US field crew physically confirmed the presence of outcropping garnet skarn at both the Mammoth and Greenstone prospects — two of the three claim areas making up the Pioneer Tungsten Project. These visual observations are not trivial. Garnet skarns of this type, where the Cretaceous Uphill Creek Granodiorite has intruded mid-Paleozoic carbonate-rich sedimentary rocks, are the precise geological setting responsible for the tungsten mineralisation in the broader district.
The skarns are defined by garnet (andradite/grossular), pyroxene (hedenbergite), and scheelite (CaWO₄) — the last of these being the tungsten-bearing mineral. Massive garnet skarns up to 25 metres thick are known to occur in adjacent ground, with local assays on neighbouring tenure reaching over 0.5% WO₃.
The 24 rock chip samples collected across Mammoth and Greenstone span a range of skarn types — from pale green garnet skarns to calc-silicate hornfels, to samples from historical trench walls — and have been submitted for multielement analysis. Results are anticipated before the end of June 2026.
"Red Mountain's claims encompass similar geology and lie adjacent to claims purchased in November 2025 by Almonty Industries (Market Cap AU$6.6 billion), hosting the Gentung Tungsten Deposit, with a mineral resource of 6.83Mt @ 0.315% WO₃; as well as the Ivanhoe and Lost Creek Mines, which are estimated to have collectively produced 680kt of tungsten ore in the 1950s and 1970s."
Magnetic Modelling: A Window Beneath the Surface
Beyond what the team could see at surface, Red Mountain engaged specialist firm Arrow Geosciences to produce a 3D model of magnetic susceptibility using publicly available USGS airborne magnetic data from the 2023 Butte survey extension. The modelling used 25m³ cells and was corrected using Virtual Resultant Magnetisation Intensity (VRMI) to isolate the magnetic signature of the Uphill Creek Granodiorite — the same intrusive body responsible for skarn formation across the district.
The results are significant for several reasons:
- The Gentung tungsten resource (owned by Almonty Industries), which sits at approximately 200 metres depth on a near-flat-lying contact between Snowcrest Range Group limestone and the Granodiorite, is clearly expressed as a magnetic high in the modelled data — validating the approach.
- Similar magnetic highs extend beneath Red Mountain's Mammoth and Greenstone claims, interpreted as subsurface extensions of the Granodiorite at comparable, drillable depths.
- At Greenstone, there is a direct spatial relationship between the magnetic high and mapped garnet skarn at surface — a particularly encouraging alignment of geological indicators.
- At Mammoth, the model reveals a central "hole" interpreted as a later intrusion of the non-magnetic Grayling Lake Granite into the Uphill Creek Granodiorite — an observation consistent with the known district geology.
- The Lost Creek prospect presents a contrasting picture, with the modelled magnetic edge of the Granodiorite appearing to dip very steeply from surface, suggesting a different structural geometry less conducive to flat-lying skarn development.
The table below summarises the magnetic modelling outcomes across the three claim areas:
| Prospect | Magnetic High Observed? | Interpreted Geometry | Skarn at Surface | Priority for Drilling |
|---|---|---|---|---|
| Mammoth | Yes | Shallow subsurface Granodiorite extension | Confirmed | High |
| Greenstone | Yes | Shallow subsurface Granodiorite extension, aligned with surface skarn | Confirmed | High |
| Lost Creek | Muted / steep | Steeply dipping Granodiorite margin | Not confirmed at surface | Lower (pending further work) |
Understanding Garnet Skarn Tungsten Deposits
What Is a Garnet Skarn?
A skarn forms when hot, mineral-rich fluids expelled from a cooling granite or granodiorite intrusion react chemically with adjacent carbonate rocks (such as limestone). This metasomatic process replaces the original carbonate with a new suite of calcium-silicate minerals — most importantly, garnet and pyroxene. In tungsten-bearing skarns, the element tungsten is carried in these fluids and precipitates as scheelite (CaWO₄), often as fine grains within the garnet-pyroxene matrix.
Why Does This Matter for Investors?
Skarn-hosted tungsten deposits can be high-grade, relatively compact, and amenable to both underground and open-pit mining. Critically, the geological controls are well understood — the mineralisation forms at the contact between the intrusion and the limestone, meaning once the geometry of that contact is mapped (as magnetic modelling can help achieve), drill targets can be defined with meaningful precision.
The district-scale precedent here — with a confirmed 6.83Mt @ 0.315% WO₃ resource on adjacent ground — provides a credible benchmark for what the same geological system can produce.
Glossary of Key Terms
| Term | Definition |
|---|---|
| Garnet Skarn | A rock type formed by metasomatic replacement of carbonate rocks, characterised by garnet and pyroxene minerals |
| Scheelite (CaWOâ‚„) | The primary tungsten-bearing mineral in skarn deposits; calcium tungstate |
| WO₃ | Tungsten trioxide — the standard reporting unit for tungsten grade |
| Granodiorite | An intrusive igneous rock that acts as the fluid and heat source for skarn mineralisation |
| Magnetic Susceptibility | A measure of how strongly a rock responds to a magnetic field — used to map intrusive bodies underground |
| VRMI | Virtual Resultant Magnetisation Intensity — a technique used to correct magnetic data for variations in magnetisation direction |
| Rock Chip Sampling | Surface sampling technique collecting representative pieces of rock for geochemical analysis |
| Float | Rock fragments that have been transported from their original location by weathering or gravity |
The Neighbourhood: A Tungsten District With a Proven Track Record
One of the most compelling aspects of the Pioneer Project is its geological and geographic context. Red Mountain's three claim areas sit along the eastern margin of the Mount Torrey Batholith in southwest Montana — a proven tungsten-producing district with a documented history stretching back to the early 1950s.
The historical production record for the immediate district is well documented:
| Mine | Period of Operation | Total Production | Average Grade |
|---|---|---|---|
| Ivanhoe Mine (Open Pit) | 1953–1957 | 567kt | 0.35% WO₃ |
| Lost Creek Mine | 1952–1956 | 19kt | 0.18% WO₃ |
| Ivanhoe Mine (Rebuilt) | 1971–1975 | Part of ~680kt combined | — |
| Greenstone Mine | 1950s | 900kg sorted ore | 1.2% WO₃ |
The combined estimated production from the district in the 1950s and 1970s is approximately 680kt of tungsten ore. This is the same mineralised system — the same geological contact, the same skarn style, the same host rocks — that Red Mountain's claims are situated within.
Almonty Industries, now a AU$6.6 billion market capitalisation company listed on NASDAQ, TSX, ASX, and Frankfurt, purchased the adjacent Gentung claims in November 2025. Furthermore, it holds the 6.83Mt @ 0.315% WO₃ Gentung Tungsten Deposit — a resource that sits at approximately 200 metres depth on the same granodiorite-limestone contact that Red Mountain's magnetic modelling suggests extends beneath Mammoth and Greenstone.
What Comes Next: A Clear Near-Term Pathway
Red Mountain has outlined a disciplined, staged programme of work that could move from surface confirmation to drill testing within months, subject to positive analytical results.
Immediate Priorities (June 2026)
- Receive and assess multielement analytical results from the 24 rock chip samples submitted from Mammoth and Greenstone — expected before end of June.
- Complete additional surface geological mapping and sampling across all three claim areas during June.
Subject to Positive Assay Results
- Define drill targets to test subsurface extensions of outcropping skarn mineralisation at one or more prospects.
- Secure necessary environmental and regulatory approvals for a drilling programme.
- Execute a drilling programme targeting downdip extensions of surface mineralisation — potentially during the current northern hemisphere summer.
The company has indicated it intends to move as rapidly as possible through each of these steps. In addition, the shallow depth of analogous mineralisation at Gentung (~200 metres) suggests that conventional, cost-effective drilling techniques would be appropriate for initial testing.
The Investment Case in Focus
Red Mountain Mining enters this next phase with a set of genuinely differentiated characteristics that warrant investor attention.
1. 100% Ownership of a Strategically Located Project
The Pioneer Tungsten Project claims were acquired under an option agreement and are now 100% owned by Red Mountain. The claims sit on US Bureau of Land Management (BLM) managed land, providing secure tenure under US Federal Law.
2. Geological Validation From Surface to Depth
The combination of physically confirmed outcropping garnet skarn at surface and independent magnetic modelling identifying analogous subsurface bodies at Mammoth and Greenstone provides a two-layered validation of the exploration thesis. Consequently, both surface geology and geophysics are pointing in the same direction.
3. A World-Class Neighbour as a De-Risking Reference Point
Almonty Industries' adjacent Gentung deposit — the same geological system, the same contact, the same mineralisation style — provides an independently verified resource estimate as a benchmark. The fact that a company now capitalised at AU$6.6 billion chose to acquire ground in this exact district in November 2025 speaks to the perceived value of the geology.
4. Near-Term, Binary Catalysts
The upcoming assay results from 24 rock chip samples represent a clear, near-term binary catalyst. Positive tungsten grades in the skarn samples submitted for analysis would directly underpin the case for drill testing and provide the market with quantitative confirmation of the mineralisation thesis.
5. A Broader Critical Minerals Portfolio
Beyond Pioneer, Red Mountain operates across a portfolio of critical minerals projects in the US and Australia. For instance, this includes:
- Armidale Antimony-Gold Project (NSW, Australia) — multiple high-grade antimony rock chip samples up to 39.3% Sb
- Utah Antimony Project — adjacent to the Antimony Canyon Project (ASX: AT4)
- Thompson Falls Antimony Project — initial assay results up to 36.5% Sb, near the NYSE: UAMY Antimony Smelter
- Two Idaho Antimony Projects
This diversification across tungsten and antimony — both recognised critical minerals — positions Red Mountain across multiple commodity themes simultaneously.
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Why Investors Should Keep a Close Watch on RMX
Red Mountain Mining is at an early but genuinely exciting inflection point at the Pioneer Project. The company has done exactly what exploration companies should do at this stage: gone to the field, confirmed the geology with its own eyes, collected systematic samples, and applied rigorous geophysical modelling to understand what lies beneath the surface.
The results of that work have returned a coherent picture — outcropping skarn at two prospects, magnetic bodies consistent with shallow granodiorite extensions at both, and a clear pathway to drill testing if the assay results confirm tungsten mineralisation. The Red Mountain Mining Pioneer Tungsten Project tungsten discovery in Montana continues to build a compelling case with each new data set.
The proximity to Almonty's Gentung deposit is not incidental. It is a direct geological analogue on adjacent ground, and the magnetic modelling specifically validates that the same subsurface architecture hosting the 6.83Mt resource appears to extend beneath Red Mountain's claims.
Key Takeaway: Red Mountain Mining has positioned itself within one of Montana's most historically productive tungsten districts, with outcropping garnet skarn confirmed at surface and magnetic modelling identifying analogous subsurface bodies at drillable depths. With rock chip assay results due before end of June and drill targeting potentially to follow within months, investors should watch closely for results that could catalyse a rapid move toward systematic drill testing of this 100%-owned pioneer project.
Ready to Track Red Mountain Mining's Next Move at Pioneer?
With outcropping garnet skarn confirmed at surface, compelling magnetic signatures pointing to drillable subsurface targets, and rock chip assay results due before the end of June, Red Mountain Mining (ASX: RMX) is approaching a pivotal moment at its 100%-owned Pioneer Tungsten Project. Investors seeking to follow the company's progress — from imminent assay results through to potential drill programme execution — can access the latest updates, project details, and investor materials directly at the Red Mountain Mining Investor Hub.
