Vancouver, British Columbia--(Newsfile Corp. - September 22, 2026) - Myriad Uranium Corp. (CSE: M) (OTCQB: MYRUF) (FSE: C3Q) ("Myriad" or the "Company") is pleased to announce the results of an initial testing campaign conducted by DISA Uranium™ Corporation ("DISA Uranium") in 2026 with samples from Myriad Uranium. The primary objective of testing was to determine how efficiently DISA's high-pressure slurry ablation technology ("HPSA™") could concentrate uranium and improve recovery of uranium from the concentrated mass fraction.

Myriad's CEO, Thomas Lamb, commented: "Wyoming's DISA Uranium, in partnership with IsoEnergy and with backing from other uranium industry leaders, has developed a slurry ablation technology, which is potentially tailor-made for Copper Mountain's uraniferous material. Simply put, initial tests confirm that the process can reduce rock mass by about 70%, while producing a 3-fold increase in grade. More testing will be required at scale, but this is a highly encouraging initial result."

HPSA™ test results indicate the following:

• Effective particle size reduction (setting up the size-based separation that follows).

• Meaningful reduction of uranium in the clean coarse material achieved (74.5% to 87.9%). Most of the uranium was successfully stripped out of the coarse rock, which is typically discarded as waste.

• 78.8% reduction in Ra-226 activity and an 83.5% reduction in Th-230 activity, leaving cleaner waste material for handling and disposal.

• Calculated recoveries of uranium in the fines concentrate were 83.9% (over the first-time interval sample) and 90.6% (over the second time interval sample). This is only a marginal increase in recovery over a longer period of ablation.

• HPSA™ test results indicate that with minimal particle collisions, the process concentrated 83.9% of the uranium into 29.3% of the overall mass, i.e. a roughly 70% reduction in mass requiring further processing, while keeping most of the uranium.

• Improved recovery of the concentrated mass fraction, leaving a cleaner coarse (waste) fraction. More uranium ends up in the small concentrate stream, and what's left over (the coarse material) is correspondingly cleaner/lower grade, meaning less material requiring further processing.

• Early leach testing by Hazen Research (1976) for Union Pacific found greater than 92% uranium recovery (with most samples >96%) using a dilute sulphuric acid leach. This, combined with a preconcentration method such as HPSA™, could result in significant overall reduction in beneficiation costs.

DISA Uranium's HPSA™ Methodology and Results

Myriad provided approximately 50 kg of sample material from its 2024 drilling campaign at Canning to DISA Uranium for HPSA™ testing. The HPSA™ process involves the collision of two slurry streams at high pressures to liberate minerals from gangue material for recovery in the fines concentrate. As particles collide at high velocities inside the HPSA™ collision chamber, they fracture at their natural grain boundary lines, which allows minerals to be liberated and recovered. Samples were collected at various time intervals in the unit to show increased liberation and recoveries over time.

The objectives of testing were to:

• Provide elemental analysis before and after HPSA™ processing.

• Analyse uranium and overall mass shifts at different collision intervals throughout HPSA™ processing.

• Determine elemental recoveries in the minus 53-micron size fraction post-HPSA™ processing.

The composite sample was subjected to initial material characterization to determine particle size distribution (PSD), ICP-MS for uranium, and radionuclide activity analysis for Ra-226 and Th-230. This was followed by HPSA™ testing in a batch-style HPSA™ unit (Figure 1) under set parameters and variable testing times. Collected samples were then characterized by a PSD and ICP-MS for uranium. The elemental analysis by ICP-MS for uranium and radionuclide activity analysis for Ra-226 and Th-230, was performed by a third-party laboratory (Energy Labs).

Figure 1 HPSA test unit.

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ICP-MS results indicated that the total percent reduction of uranium concentration ranged from 74.5% to 87.9%; the total percent recovery to the fines concentrate ranged from 83.9% to 90.6%. At the first time interval, 83.9% of the uranium was recovered in 29.3% of the mass. At the second time interval, the recovery of uranium increased by 6.72%, with an additional 8.19% of the mass in the fines concentrate relative to first (Table 1).

Table 1 Results summary of ICP-MS for uranium (bulk feed and HPSA products).

The radionuclide activity analysis indicated successful reduction in contaminants in the clean coarse material. For time sample 1, the percent reduction of Ra-226 activity was 78.8%, and the percent reduction of Th-230 activity was 83.5%.

Conclusion

The results of the testing campaign indicated that HPSA™ processing was successful in uranium liberation and recovery. Meaningful size reduction was also achieved. The percent reduction of uranium in the clean coarse material ranged from 74.5% to 87.9%. Meaningful reduction in radionuclide activity was also achieved. Significant amounts of uranium were recovered in the fines concentrate. ICP-MS indicated that HPSA™ technology was able to concentrate 83.9% of the uranium in 29.3% at the first time interval, and 90.6% of the uranium was concentrated in 37.5% of the mass at the second time interval sample. Uranium concentration in the fines concentrate was found to increase with additional turnovers. Results of a full-scale operation are expected to align closely with the first time interval taken from the laboratory batch system, but this can easily be engineered and optimized depending on target recoveries and mass pull.

This testing demonstrated that the HPSA™ technology can improve the recovery of uranium for the material provided by Myriad Uranium. Future testing would be beneficial to continue to optimize and improve selective liberation of the uranium particles for increased recovery.

Qualified Person

The scientific and technical information in this news release, including the eU₃O₈ methodology and historical disclosure, has been reviewed and approved by George van der Walt, MSc., Pr.Sci.Nat., FGSSA, a "Qualified Person" as defined under NI 43-101. Mr. van der Walt is a Principal Consultant with The MSA Group (Pty) Ltd, an independent consultancy, and is independent of the Company for the purposes of NI 43-101. A Qualified Person has not done sufficient work to verify historical exploration results or to classify the historical estimates referred to in this news release as current mineral resources or mineral reserves, and Myriad is not treating such historical estimates as current mineral resources or mineral reserves.

About Myriad Uranium Corp.

Myriad Uranium Corp. holds a 100% interest in the Copper Mountain Uranium Project in Wyoming, USA. Copper Mountain hosts multiple historic uranium deposits and past-producing mines, including the Arrowhead Mine (approximately 500,000 lbs U₃O₈ produced). Union Pacific conducted extensive exploration and development in the district during the late 1970s, including approximately 2,000 boreholes and advanced mine planning, before the uranium market downturn in 1980. Union Pacific is estimated to have invested approximately C$125 million (2026 dollars) in the project, generating significant historical resource estimates.

A news release detailing a comprehensive assessment of Copper Mountain's uranium endowment by Bendix Engineering for the US Department of Energy published in 1982 can be viewed here.

Myriad holds a 10% free carried interest in the Red Basin Uranium Project, recently sold to 8VC- and Overmatch-backed Subatomic Industries. Red Basin carries significant historical resource estimates from extensive drilling by Occidental Oil in the late 1970s, and also hosts vanadium, which has been designated a strategic and critical mineral by the U.S. government. Note the caution on historical estimates below.

Myriad's 100%-owned Breccia Pipe Project in Arizona comprises at least 23 breccia pipes that are prospective for uranium and REEs. One of the pipes, the Wate Pipe, was previously owned and explored by Energy Fuels and is the subject of a historical resource estimate.

Note: A qualified person has not done sufficient work to classify the Copper Mountain, Red Basin, and Breccia Pipe Project historical estimates as current mineral resources or reserves and Myriad is not treating historical estimates as current resources or reserves. Myriad intends to conduct further work to determine whether the historical estimates can be verified and, if appropriate, supported by current mineral resource estimates.

For further information, please refer to Myriad's disclosure record on SEDAR+ (www.sedarplus.ca), contact Myriad by telephone at +1.604.418.2877, or refer to Myriad's website at www.myriaduranium.com.

About DISA Uranium

DISA Uranium™ Corporation (DISA Uranium) is redefining American uranium recovery and production. Headquartered in Casper, Wyoming, the veteran-led Company recovers uranium and vanadium from abandoned uranium mine (AUM) waste, remediates legacy sites left across the western United States, and applies its patented high-pressure slurry ablation technology (HPSA™) to make conventional uranium production cleaner, more efficient, and more economic. DISA Uranium holds the only U.S. Nuclear Regulatory Commission (NRC) license to treat and recover AUM waste across multiple sites - and with a growing conventional resource base behind it, the Company is building the domestic capacity to turn American waste and American ore into American fuel. The mission is simple: restore the past while powering the future and rebuild a secure domestic uranium supply chain.

Forward-Looking Statements

This news release contains "forward-looking information" that is based on the Company's current expectations, estimates, forecasts and projections. This forward-looking information includes, among other things, the Company's business, plans, outlook and business strategy. The words "may", "would", "could", "should", "will", "likely", "expect," "anticipate," "intend", "estimate", "plan", "forecast", "project" and "believe" or other similar words and phrases are intended to identify forward-looking information. The reader is cautioned that assumptions used in the preparation of any forward-looking information may prove to be incorrect, including with respect to the Company's business plans respecting the exploration and development of the Company's mineral properties, the proposed work program on the Company's mineral properties and the potential and economic viability of the Company's mineral properties. Forward-looking information is subject to known and unknown risks, uncertainties and other factors that may cause the Company's actual results, level of activity, performance or achievements to be materially different from those expressed or implied by such forward-looking information. Such factors include, but are not limited to: inability to verify historical data, no assurance of defining mineral resources, permitting, drilling delays and changes in economic conditions or financial markets; increases in costs; litigation; legislative, environmental and other judicial, regulatory, political and competitive developments; and technological or operational difficulties. This list is not exhaustive of the factors that may affect our forward-looking information. These and other factors should be considered carefully, and readers should not place undue reliance on such forward-looking information. The Company does not intend, and expressly disclaims any intention or obligation to, update or revise any forward-looking information whether as a result of new information, future events or otherwise, except as required by applicable law. The CSE has not reviewed, approved or disapproved the contents of this news release.

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