Vancouver, British Columbia--(Newsfile Corp. - August 24, 2026) - Myriad Uranium Corp. (CSE: M) (OTCQB: MYRUF) (FSE: C3Q) ("Myriad" or the "Company") advises that the press release issued on Thursday August 20, 2026 contained an error.

The release stated in its Historical Resource Estimates section that the historical estimate of 26.63 Mlbs eU₃O₈ is contained in "44.1 Mt at 171 ppm eU₃O₈", using a 100-ppm cut-off. This should have read "48.95 Mt at 269 ppm eU₃O₈".

All other information in the original news release remains unchanged.

Historical Resource Estimates

The historical estimate of 26.63 Mlbs eU₃O₈ in 48.95 Mt at 269 ppm eU₃O₈, using a 100 ppm cut-off, was compiled from internal Rocky Mountain Energy Company reports, which are summarised in a report titled "Copper Mountain Exploration Project Report" by Southard, G.G., et. al. (1979). A Qualified Person has not done sufficient work to classify the historical estimate as current mineral resources or mineral reserves, and Myriad is not treating the historical estimate as current mineral resources or mineral reserves.

The historical estimates were completed using polygonal methods based on modelled mineralization geometries. The historical estimates used U.S. Bureau of Mines categories at the time, including terms described as "Inferred" and "Indicated," which are not current CIM terminology and should not be interpreted as current mineral resource categories. Details of the historical resource estimates are available in the current NI 43-101 Technical Report. While the QP has determined that the historical estimates described in this news release are relevant to the Copper Mountain Project Area, are reasonably reliable given the authors and circumstances of their preparation, and are suitable for public disclosure, the estimates are decades old and based on drilling data for which the logs are, as of yet, predominantly unavailable. Readers are cautioned not to place undue reliance on these historical estimates as an indicator of current mineral resources or mineral reserves at the Project Area. Also, while the Copper Mountain Project Area contains all or most of each deposit referred to, some of the resources referred to may be located outside the current Copper Mountain Project Area.

Inherent limitations of the historical estimates include that the nature of mineralization (fracture hosted) makes estimation from drill data less reliable than other deposit types (e.g. those that are thick and uniform). From Myriad Uranium's viewpoint, limitations include that the Company has not been able to verify the original data itself and that the estimates may be optimistic relative to subsequent work which applied a "delayed fission neutron" (DFN) factor to calculate grades. On the other hand, DFN is controversial, in that the approach is viewed by some experts as too conservative. Nevertheless, it was applied in later resource estimations by Union Pacific relating to Copper Mountain. To verify the historical estimates and re-state them as current resources, a program of re-drilling is required to generate new data that can be used to establish the correlation and continuity of geology and grades between boreholes with sufficient confidence to estimate mineral resources.

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.

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.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/311007