Stillwater Critical Minerals Corp. reported results of rhodium assays from the 2025 resource expansion drill campaign and highlights chromium defined at the Company?s 100%-owned Stillwater West project in Montana, USA. Rhodium assays from the 2025 drill campaign confirm widespread rhodium mineralization at potential co-product levels across the Chrome Mountain and Iron Mountain resource areas within the broader district-scale polymetallic system including the Pine and Picket Pin target areas at Stillwater West.
Results will be incorporated into the updated Mineral Resource Estimate targeted for the first half of 2026, including the current 115,000-ounce rhodium component which represents the only known rhodium resource in the United States. Drilling intersected up to 0.167 g/t Rh over 1.22 metres in hole CM2025-01 from 358m depth, with a second interval of 0.107 g/t Rh over 1.22m from 388m, supporting rhodium as a potential co-product within the broader polymetallic system. Approximately seven kilometers to the east, IM2025-01 returned 1.22m at 0.148g/t Rh starting at 272m, continuing to demonstrate the district-scale nature of the mineralized system.
Previous drilling at Chrome Mountain also intersected elevated Rh values including 1.13 g/t Rh over 1.2m in hole CM2023-03 and 0.162 g/t Rh over 3.7m in hole CM2023-01. Historic rock sample programs returned up to 5.78 g/t Rh in the HGR deposit area at Iron Mountain, and up to 1.07 g/t Rh at Chrome Mountain. Rock sampling by Stillwater from 2019 to 2022 included 31 rhodium assays with an average of 0.162 g/t Rh and a maximum value of 0.644 g/t Rh across known deposit areas and also the pre-resource Picket Pine and Pine targets.
The five-year average Rh price and the current spot price is approximately USD 10,000/oz. Rhodium is identified as a critical mineral in the United States and is used in emissions control, high-temperature alloys, defense-related industrial applications and other advanced technologies. In addition, Stillwater has defined a resource of 2.3 billion pounds of contained chromium at Stillwater West, underscoring the project’s strategic significance as a potential domestic source of a mineral essential to steel production, industrial manufacturing and defense related applications.
Highlighted significant intercepts with grade-thickness values over 7 percent-meter recovered NiEq are presented above, except as noted. Recovered Nickel Equivalents (NiEq) are presented for comparative purposes using conservative long-term metal prices: USD 8.00/lb nickel (Ni), USD 4.50/lb copper (Cu), USD 15.00/lb cobalt (Co), USD 1,250/oz platinum (Pt), USD 1,250/oz palladium (Pd), USD 3,000/oz gold (Au), and USD 6,500/oz rhodium (Rh). NiEq is determined as follows: NiEq% = [Ni% x recovery] + [Cu% x recovery x Cu price/Ni price] + [Co% x recovery x Co price /Ni price] + [Pt g/t x recovery /31.103 x Pt price /Ni price /2,204 x 100] + [Pd g/t x recovery /31.103 x Pd price /Ni price /2,204 x 100] + [Au g/t x recovery /31.103 x Au price /Ni price /2,204 x 100].
In the above calculations: 31.103 = grams per troy ounce, 2,204 = lbs per metric tonne, and 100 and 0.01 convert assay results reported in % and g/t. The following recoveries have been assumed for purposes of the above equivalent calculations: 85% for Ni and 90% for all other listed metals, based on recoveries at similar nearby operations. Total metal equivalent values include both base and precious metals. In terms of dollar value, 0.20% nickel equates to a copper value of 0.36%, or a palladium value of 0.88 g/t, using the above metal values.
Intervals are reported as drilled widths and are believed to be representative of the actual width of mineralization. The Picket Pin horizon is a historically known high-grade reef-type PGE target situated above the J-M Reef in the upper stratigraphy of the Stillwater Igneous Complex. Work by Stillwater in 2019 returned rock samples up to 0.162 g/t Rh alongside 5.09 g/t 3E (Pt, Pd, and Au), confirming the presence of rhodium as a co-product in this pre-resource target area.
The Pine target is a high-grade gold, nickel and PGE target that the Company is advancing towards a formal resource estimate. A 2019 rock sample returned 0.541 g/t Rh and a 2022 trench sampling campaign returning an average of 9.0 g/t Au, 0.69 g/t Pd, and 0.69 g/t Pt, with historic drilling recording up to 31.02 g/t 3E (Pt, Pd and Au) over 2.6 m. Stillwater West benefits from being a large and polymetallic system that offers a balanced suite of base and precious metals, many of which are now listed as critical. Rhodium has been identified by the U.S. Geological Survey as one of the highest-risk critical minerals in terms of potential economic impact from supply disruptions.
The metal is produced solely as a co-product and has limited domestic supply in the United States. Rhodium is a critical component in catalytic converters, used alongside platinum and palladium to reduce vehicle emissions. It is also increasingly recognized as strategically important to U.S. national security and the defense industrial base due to its role in high-performance, high-temperature, and corrosion-resistant applications.
In addition to rhodium, Stillwater West contains multiple other minerals considered strategically important to U.S. industrial, energy and defense supply chains, including nickel, copper, cobalt, chromium and platinum group metals. Chromium is of particular importance due to the United States? near-total reliance on imports and limited domestic production.
Historic chromium production from the Stillwater Complex is well documented, and the district continues to host the majority of known domestic chromium resources. Current mineral resources at Stillwater West include nickel, copper, cobalt, chromium, palladium, platinum, rhodium and gold, in addition to yet-to-be-quantified amounts of iridium and ruthenium. The Company continues to engage with U.S. government agencies as it advances Stillwater West through ongoing technical and development studies.
2025 drill core samples were analyzed by ACT Labs in Vancouver, B.C. Sample preparation: crush (< 7 kg) up to 80% passing 2 mm, riffle split (250 g) and pulverize (mild steel) to 95% passing 105 µm included cleaner sand. Gold, platinum, and palladium were analyzed by fire assay (1C-OES) with ICP finish. Selected major and trace elements were analyzed by peroxide fusion with 8-Peroxide ICP-OES finish to insure complete dissolution of resistate minerals.
Following industry QA/QC standards, blanks, duplicate samples, and certified standards were also assayed. Mr. Mike Ostenson, P.Geo., is the qualified person for the purposes of National Instrument 43-101, and he has reviewed and approved the technical disclosure contained in this news release. Mr. Ostenson is a Geologist at Stillwater and is not independent of the Company.