Standard Uranium Confirms Strong Radioactivity at Surface During Successful Exploration Program at the Rocas Uranium Project

Rhea-AI Summary

Standard Uranium (OTCQB: STTDF) reported preliminary results from its September 30–October 8, 2025 prospecting program at the 4,002-hectare Rocas Project, ~75 km southwest of Key Lake. Field crews recorded strong surface radioactivity including peak handheld scintillometer readings up to 33,000 cps, 73 readings >300 cps and 10 readings >10,000 cps. Geological mapping traced deformed, hydrothermally altered basement lithologies along > 7.5 km of exploration strike. A 2024 high-resolution ground gravity survey highlighted gravity lows and priority targets along conductive corridors. Historical grab samples on ~900 m of strike returned up to 0.498 wt% U3O8.

A maiden diamond drill program is planned for 2026 to test high-priority targets.

Positive

• Peak radioactivity measured at 33,000 cps
• 73 handheld readings >300 cps; 10 >10,000 cps
• 7.5 km of mapped exploration strike with altered basement
• Maiden diamond drill program planned for 2026
• Historical grab sample up to 0.498 wt% U3O8

Negative

• Historical sampling data remain unverified by the company
• No drill testing completed to date on Rocas targets
• Handheld scintillometer readings are not directly convertible to uranium grade

Vancouver, British Columbia--(Newsfile Corp. - October 16, 2025) - Standard Uranium Ltd. (TSXV: STND) (OTCQB: STTDF) (FSE: FWB:9SU0) ("Standard Uranium" or the "Company") is pleased to announce preliminary results from its 2025 exploration program at the Rocas Uranium Project ("Rocas", or the "Project"), currently under a three-year earn-in option agreement with Collective Metals Inc. ("Collective Metals") (CSE: COMT). From September 30^th to October 8^th, 2025, the Company completed a detailed mapping and sampling program across historical uranium showings and zones of interest on the Project, identifying multiple zones of strong radioactivity.

Highlights:

• Strong Radioactivity at Surface - Verification of strong radioactivity at multiple historical uranium showings, with several handheld scintillometer measurements exceeding 10,000 counts per second ("cps") at surface.

• Discovery of New Radioactive Showings - Scintillometer prospecting identified previously undocumented radioactive anomalies across the Project area within lithologies favorable for uranium and Rare Earth Element ("REE") mineralization.

• Prime Location - Geological mapping along structural and electromagnetic ("EM") trends across the Project confirmed the presence of deformed and hydrothermally altered basement lithologies along more than 7.5 km of exploration strike length south of Key Lake.

• New Uranium Targets - Results from a high-resolution ground gravity survey completed in 2024 highlight potential alteration halos and high-priority exploration targets along well-defined structural corridors. A diamond drill program is planned for 2026 to test targets identified and prioritized through detailed exploration activities carried out this year.

"The confirmation of strong radioactivity at the Rocas Project is an exciting step forward, directly validating historical uranium showings and highlighting the Project's discovery potential," said Sean Hillacre, President & VP Exploration of Standard Uranium. "Surface grab samples and technical information collected during this program not only strengthen our geological model but also add real value ahead of a maiden drill program planned for next year."

Figure 1. Regional map of Standard Uranium's Rocas Project. The Project is located 75 kilometres southwest of the Key Lake Mine and Mill facilities along Highway 914.

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2025 Prospecting Program - Preliminary Results

The Rocas project comprises 4,002 hectares, located 75 kilometers southwest of the Key Lake Mine and Mill facilities along Highway 914, and approximately 72 kilometers south of the present-day margin of the Athabasca Basin (Figure 1). Beginning September 30^th and concluding October 8^th, 2025, the Standard Uranium technical team completed a detailed mapping, prospecting, and sampling program to ground-truth historical uranium showings at surface on the Project.

• A total of 16 outcrop and boulder grab samples have been submitted to Saskatchewan Research Council Geoanalytical Laboratories in Saskatoon, SK for whole-rock, uranium, and REE geochemical analysis.

• Prospecting confirmed several uraniferous outcrops and boulders across the Project, including SMDI showing 5781 (1,100 ppm U)¹. Anomalous^* radioactivity with a peak of >33,000 cps was measured at SMDI showing 5781 (Figure 2) with several other instances of elevated radiometry were noted, locally up to 26,000 cps.

• A total of 73 handheld scintillometer readings of anomalous radioactivity >300 cps were recorded, including 10 measurements >10,000 cps at surface (Figure 3). Prospecting for radioactive boulders and outcrop was completed using handheld RS-120 Super-Scintillometers and RS-125 Super-Spectrometers manufactured by Radiation Solutions Inc. ("RSI").

• More than 150 detailed geological observations, structural measurements, and scintillometer readings were taken from several outcrops across the Project within the target areas, identifying deformed and hydrothermally altered basement lithologies associated with radioactivity (Figure 4).

Figure 2. Investigation at SMDI showing 5781 returned strong radioactivity across an area of 35 m. Scintillometer readings ranging from: A) 26,900 cps, B) 25,400 cps, and C) 33,000 cps.

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Figure 3. Newly discovered quartz-rich pegmatitic orthogneiss outcrop reaching upwards of 28,200 cps along the northern conductor trend. Outcrop was partially under soil cover.

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Figure 4. Oxidized metasediment outcrop with hematite and limonite alteration

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Rocas Project Exploration

The Company plans to complete the first ever drill program on the Project in 2026 to begin testing high-priority zones along the main 7.5 kilometre magnetic low/EM conductive corridor, which is host to several uranium showings and has remained un-drill tested to date.

Earlier this year, the Company contracted MWH Geo-Surveys (Canada) Ltd. to carry out a high-resolution ground gravity survey over the Rocas Project², while Convolutions Geoscience Corporation has completed subsequent processing, interpretation, and modelling of the gravity data. The ground gravity survey outlines several gravity low anomalies coincident with historical surface mineralization, lakebed geochemical anomalies, and cross-cutting fault zones along the known conductive exploration trends on the Project.

Historical airborne EM work in 2017 defined conductive trends on the Project west of and sub-parallel to the Key Lake Road shear zone, corresponding with favourable metasedimentary basement lithologies. Multiple parallel conductors, offsets, and termination points indicate the trend widening and potential cross-cutting structures. Additionally, a 2007 field sampling program identified anomalous lakebed geochemical anomalies that statistically rank as greater than 95^th percentile U, Co, V, and Zn along the conductor corridor, including high U/Th ratios³.

The Company believes the Project is highly prospective for the discovery of shallow, high-grade^** basement-hosted uranium mineralization. Positioned proximal to the margin of the Athabasca Basin, Rocas boasts shallow drill targets with bedrock under minimal glacial till cover. Historical mineralized outcrop grab samples along approximately 900 metres of strike length, returned values ranging from 587 ppm U (SN85073) up to 0.498 wt.% U₃O₈ (SN23901) and have never been drill tested⁴.

Qualified Person Statement

The scientific and technical information contained in this news release has been reviewed, verified, and approved by Sean Hillacre, P.Geo., President and VP Exploration of the Company and a "qualified person" as defined in NI 43-101 - Standards of Disclosure for Mineral Projects.

Historical data disclosed in this news release relating to sampling results from previous operators are historical in nature. Neither the Company nor a qualified person has yet verified this data and therefore investors should not place undue reliance on such data. The Company's future exploration work may include verification of the data. The Company considers historical results to be relevant as an exploration guide and to assess the mineralization as well as economic potential of exploration projects. Any historical grab samples disclosed are selected samples and may not represent true underlying mineralization.

Natural gamma radiation from rocks reported in this news release was measured in counts per second ("cps") using a handheld RS-125 super-spectrometer and RS-120 super-scintillometer. Readers are cautioned that scintillometer readings are not uniformly or directly related to uranium grades of the rock sample measured and should be treated only as a preliminary indication of the presence of radioactive minerals. The RS-125 and RS-120 units supplied by RSI have been calibrated on specially designed Test Pads by RSI. Standard Uranium maintains an internal QA/QC procedure for calibration and calculation of drift in radioactivity readings through three test pads containing known concentrations of radioactive minerals. Internal test pad radioactivity readings are known and regularly compared to readings measured by the handheld scintillometers for QA/QC purposes.

References

¹ SMDI# 5781: https://mineraldeposits.saskatchewan.ca/Home/Viewdetails/5781 & Mineral Assessment Report MAW00726: Millenmin Ventures Inc. and Inner Mongolia Minerals (Canada) Ltd., 2013

² Standard Uranium Acquires Umbra and Sable Uranium Projects and Completes Geophysical Surveys on Rocas and Atlantic Projects, Eastern Athabasca Basin, Saskatchewan. https://standarduranium.ca/news-releases/standard-uranium-acquires-umbra-and-sable-uranium-projects/

³ Mineral Assessment Report 74B09-0032: Forum Uranium Corp., 2007

⁴ Mineral Assessment Report 74B09-0007: Uranex Ltd., 1977 & SMDI# 2465: https://mineraldeposits.saskatchewan.ca/Home/Viewdetails/2465

^*The Company considers radioactivity readings greater than 300 counts per second (cps) on a handheld RS-125 Super-Spectrometer to be "anomalous".

^**The Company considers uranium mineralization with concentrations greater than 1.0 wt% U₃O₈ to be "high-grade".

About Standard Uranium (TSXV: STND)

We find the fuel to power a clean energy future

Standard Uranium is a uranium exploration company and emerging project generator poised for discovery in the world's richest uranium district. The Company holds interest in over 235,435 acres (95,277 hectares) in the world-class Athabasca Basin in Saskatchewan, Canada. Since its establishment, Standard Uranium has focused on the identification, acquisition, and exploration of Athabasca-style uranium targets with a view to discovery and future development.

Standard Uranium's Davidson River Project, in the southwest part of the Athabasca Basin, Saskatchewan, comprises ten mineral claims over 30,737 hectares. Davidson River is highly prospective for basement-hosted uranium deposits due to its location along trend from recent high-grade uranium discoveries. However, owing to the large project size with multiple targets, it remains broadly under-tested by drilling. Recent intersections of wide, structurally deformed and strongly altered shear zones provide significant confidence in the exploration model and future success is expected.

Standard Uranium's eastern Athabasca projects comprise over 43,185 hectares of prospective land holdings. The eastern basin projects are highly prospective for unconformity related and/or basement hosted uranium deposits based on historical uranium occurrences, recently identified geophysical anomalies, and location along trend from several high-grade uranium discoveries.

Standard Uranium's Sun Dog project, in the northwest part of the Athabasca Basin, Saskatchewan, is comprised of nine mineral claims over 19,603 hectares. The Sun Dog project is highly prospective for basement and unconformity hosted uranium deposits yet remains largely untested by sufficient drilling despite its location proximal to uranium discoveries in the area.

For further information contact:

Jon Bey, Chief Executive Officer, and Chairman
Suite 3123, 595 Burrard Street
Vancouver, British Columbia, V7X 1J1

Tel: 1 (306) 850-6699
E-mail: info@standarduranium.ca

Cautionary Statement Regarding Forward-Looking Statements

This news release contains "forward-looking statements" or "forward-looking information" (collectively, "forward-looking statements") within the meaning of applicable securities legislation. All statements, other than statements of historical fact, are forward-looking statements and are based on expectations, estimates and projections as of the date of this news release. Forward-looking statements include, but are not limited to, statements regarding: the timing and content of upcoming work programs; geological interpretations; timing of the Company's exploration programs; and estimates of market conditions.

Forward-looking statements are subject to a variety of known and unknown risks, uncertainties and other factors that could cause actual events or results to differ from those expressed or implied by forward-looking statements contained herein. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Certain important factors that could cause actual results, performance or achievements to differ materially from those in the forward-looking statements are highlighted in the "Risks and Uncertainties" in the Company's management discussion and analysis for the fiscal year ended April 30, 2025.

Forward-looking statements are based upon a number of estimates and assumptions that, while considered reasonable by the Company at this time, are inherently subject to significant business, economic and competitive uncertainties and contingencies that may cause the Company's actual financial results, performance, or achievements to be materially different from those expressed or implied herein. Some of the material factors or assumptions used to develop forward-looking statements include, without limitation: that the transaction with the Optionee will proceed as planned; the future price of uranium; anticipated costs and the Company's ability to raise additional capital if and when necessary; volatility in the market price of the Company's securities; future sales of the Company's securities; the Company's ability to carry on exploration and development activities; the success of exploration, development and operations activities; the timing and results of drilling programs; the discovery of mineral resources on the Company's mineral properties; the costs of operating and exploration expenditures; the presence of laws and regulations that may impose restrictions on mining; employee relations; relationships with and claims by local communities and indigenous populations; availability of increasing costs associated with mining inputs and labour; the speculative nature of mineral exploration and development (including the risks of obtaining necessary licenses, permits and approvals from government authorities); uncertainties related to title to mineral properties; assessments by taxation authorities; fluctuations in general macroeconomic conditions.

The forward-looking statements contained in this news release are expressly qualified by this cautionary statement. Any forward-looking statements and the assumptions made with respect thereto are made as of the date of this news release and, accordingly, are subject to change after such date. The Company disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required by applicable securities laws. There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements.

Neither the TSX-V nor its Regulation Services Provider (as that term is defined in the policies of the TSX-V) accepts responsibility for the adequacy or accuracy of this release.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/270619

FAQ

What surface radioactivity did Standard Uranium report at Rocas (STTDF) in October 2025?

Field prospecting recorded peak handheld readings up to 33,000 cps, with 73 readings >300 cps and 10 readings >10,000 cps.

How large is the Rocas Project and how much strike did Standard Uranium map in 2025?

Rocas covers 4,002 hectares and geological mapping confirmed > 7.5 km of exploration strike south of Key Lake.

When will Standard Uranium (STTDF) begin drilling at Rocas?

The company plans a maiden diamond drill program in 2026 to test targets identified in 2024–2025 surveys.

What geophysical work supports Rocas targets mentioned by Standard Uranium?

A 2024 high-resolution ground gravity survey outlined gravity low anomalies coincident with historical mineralization and conductive corridors.

What historical uranium grades were reported on parts of the Rocas corridor?

Historical grab samples along ~900 m of strike returned values up to 0.498 wt% U3O8 and 587 ppm U in older samples.

Are the October 2025 surface radioactivity results equivalent to confirmed uranium grades for STTDF investors?

No; the company cautions scintillometer cps readings are preliminary and not uniformly related to uranium grade, and historical data remain unverified.