The New Results Enhance Uranium Grades, Extend Mineralised Intervals, and Identify Numerous Entirely New Mineralised Intervals.

Vancouver, British Columbia--(Newsfile Corp. - October 27, 2025) - Myriad Uranium Corp. (CSE: M) (OTCQB: MYRUF) (FSE: C3Q) is pleased to report updated chemical assay results from October-November 2024 drilling at the Copper Mountain Uranium Project in Wyoming. The new results enhance uranium grades, extend mineralised intervals, and identify numerous entirely new mineralised intervals. All have significant positive implications for the Project's resource potential.

In late 2024 the Company drilled 34 boreholes at the Canning deposit at Copper Mountain. Comparisons between equivalent gamma probe-derived grades (eU₃O₈) and chemical assays (U₃O₈) from that drilling are reported here. The initial set of samples sent for chemical assay were selected strictly using a 100 ppm eU₃O₈ cut-off. The chemical assays returned significantly higher confirmed grades (U₃O₈), confirming the likelihood of radiometric disequilibrium being present in the system.

Grades of 1,000 ppm eU₃O₈ or more were found to be 60% higher on average. Grades above 500 ppm eU₃O₈ were found to be 50% higher on average. Across all samples submitted, grades were increased an average of 20%. Given these important differences, it was decided that physical sampling for chemical assays should be expanded to close sampling gaps and extend intervals where uranium may not have been accounted for.

An initial rough estimate anticipated that up to 1,500 samples could be collected for this purpose. After more rigorous review, a total of 706 additional samples were collected for the additional chemical assays. The effect of this sampling is seen especially in the mid- to lower-grade ranges of U₃O₈ assays as follows:

• At 500 ppm cut-off: 5 entirely new intervals reported.

• At 200 ppm cut-off: 20 entirely new intervals reported, and 12 intervals extended in length.

• At 100 ppm cut-off: 31 entirely new intervals reported, and 45 intervals extended in length.

The overall outcome of this additional sampling is that there is significantly more uranium reported than previously accounted for. Highlights of new intervals above 500 ppm cut-off not previously reported include:

• CAN0017: 502 ppm U₃O₈ over 2.62 ft (0.80 m) from 783.92 ft to 786.54 ft

• CAN0019: 533 ppm U₃O₈ over 4.92 ft (1.50 m) from 220.74 ft to 225.66 ft

• CAN0023: 623 ppm U₃O₈ over 1.32 ft (0.40 m) from 304.38 ft to 305.70 ft

• CAN0023: 804 ppm U₃O₈ over 2.95 ft (0.90 m) from 547.43 ft to 550.38 ft

• CAN0031: 841 ppm U₃O₈ over 2.95 ft (0.90 m) from 201.39 ft to 204.34 ft

Revised grade interval tables are provided in Appendix 1.

Myriad's CEO Thomas Lamb commented: "These new chemical assays, which extend 12 already-known intervals and reveal 70 new intervals across just 34 boreholes, build on the strong foundation established by the Bendix study discussed in a recent news release (here). That rigorous 600+-page report, prepared in 1982 for the U.S. Department of Energy and based on Union Pacific's full exploration dataset, the result of roughly C$118 million of exploration and development spending (in today's dollars), confirmed the exceptional scale of the Copper Mountain District. It estimated that a central area at Copper Mountain alone could contain a mineral endowment of 245 million pounds of uranium to a depth of 600 feet, with Myriad and its partner Rush controlling 70 percent of that ground. It was further estimated that the broader district could host a mineral endowment of 655 million pounds, of which we control nearly a third. Combined with these new assay results, the Bendix data gives us a high level of confidence in Copper Mountain's uranium potential and provides a strong technical foundation for our next stage of exploration. These results bring significant additional uranium into the picture at Canning, and hopefully foretell what we will see across the project as we engage in extensive drilling under our recently-approved plan of operations which provides clearance for 222 boreholes across the Copper Mountain Project area (announcement here). We will also endeavour to verify and go well beyond historic resources estimated by Fluor and Union Pacific, such as those totalling 16.55 Mlbs described in Appendix 2."

The boreholes represent a combination of diamond core and reverse circulation drilling that was planned to verify mineralization identified in drilling by Union Pacific in the late 1970s and test a grade shell model (above 0.05% eU₃O₈) created from cross-sections, as reported here and here. All reported assay results are represented by the borehole locations indicated on Figure 1 and Table 2 below.

Figure 1: Map of completed boreholes and grade above cut-off.

To view an enhanced version of this graphic, please visit:
https://images.newsfilecorp.com/files/6301/271962_6236e512c4c3abc6_002full.jpg

Table 2: Collar details for boreholes completed by Myriad

Drilling

Drilling was undertaken by Harris Exploration using two diamond core (DD) rigs producing HQ (63.5 mm / 2.5 in) core diameter and 96 mm (3.78 in) in hole diameter, and one reverse circulation (RC) rig using a 140 mm (5.5 in) hammer bit. Core samples were packed into core trays and transported to Riverton for further processing. RC hole runs were drilled at 5 ft intervals and split on site by a rig-mounted cyclone splitter to produce two representative samples that were then transported to Riverton for further processing.

Downhole Logging

Downhole logging was performed by DGI Geoscience (DGI) using a combination of Spectral Gamma Ray (SGR) probe for gamma data, and Optical Televiewer and/or Acoustic Televiewer for structural data. The probes are manufactured by Mount Sopris Instruments with details as follows:

• QL40 SGR BGO (Sx): Measures the energy of gamma emissions from natural sources within formations crossed by a borehole. It counts the number of gamma emissions at each energy level aiding in lithological determination and correlation. The probe use a Bismuth Germanium Oxide scintillation crystal.

• QL40 SGR 2G CeBr3 (Sx): Measures the energy of gamma emissions from natural sources within formations crossed by a borehole. It counts the number of gamma emissions at each energy level aiding in lithological determination and correlation. The probe uses a CeBr3 (Cerium Bromide) scintillation crystal.

• QL 40 ABI 2G (At, Gr): Captures high-resolution, oriented images of the borehole wall, allowing the orientation of acoustically visible features to be determined. This includes fractures, bedding/rock fabric, breakouts, bedding planes and other structural features. Contains a built in Natural Gamma sensor that measures the gamma emissions from natural sources in the formation.

• QL OBI 2G (Ot, Gr): Captures a high-resolution, oriented image of the borehole wall using a CMOS digital image sensor, allowing the orientation of features to be determined. This includes fractures, bedding/rock fabric, veins, lithological contacts, etc. Contains a built in Natural Gamma sensor that measures the gamma emissions from natural sources in the formation.

The spectral gamma probes measure the full energy spectrum of the gamma radiation emitted naturally from within the formations crossed by a borehole. A Full Spectrum Analysis (FSA) was performed on the recorded energy spectra. The FSA derived, in real time, the concentration of the three main radioisotopes ⁴⁰K, ²³⁸U, ²¹²Th, and thus also provided insight into the mineral composition of the formations. DGI also ran optical and acoustic televiewer, when hole conditions allowed, to obtain downhole structural information. Borehole paths were measured using a gyroscopic deviation tool.

Initial manufacturer calibration certificates were provided to Myriad by DGI. Downhole gamma measurements were checked for a repeatability by comparing down and up runs in the borehole. DGI provided conversion of API units measured by the spectral gamma probes to eU₃O₈ concentrations using a standard conversion theory and formula.

Geological Logging, Sampling and Analysis

Description of geological features (lithology, structure and alteration) was undertaken prior to sampling according to standardized logging templates. Core sampling intervals were selected primarily on the basis of lithological changes and in conjunction with radiometric intervals identified from the downhole spectral gamma probe measurements (using a 100-ppm cut-off). Core sample lengths are limited to a maximum of 3 feet and adjusted to a minimum of 1 foot, where appropriate, to capture significant features in the core. Reverse Circulation samples were collected and split at the rig in 5-foot intervals, with samples being selected based on downhole spectral gamma probe measurements (using a 100-ppm cut-off).

Samples were prepared and analysed at Paragon Geochemical, located in Sparks, Nevada. Sample preparation involved inventory, weighing, drying at 100°C, crushing to 70% passing 10 mesh, riffle splitting 250 g and pulverizing to 85% passing 200 mesh. The requested sample analysis package for trace and ultra-trace level geochemistry was a Multi-Element Suite (48 elements) using a Multi-Acid digest with ICP-MS.

Quality Assurance and Quality Control

Quality Assurance was achieved by implementing a set of Standard Operating Procedures (SOP) for logging and sampling. Quality Control in sampling and analysis was achieved by insertion of Blanks, Standards (Certified Reference Materials) and laboratory split (Duplicates) at a minimum rate of 5% each. Inspection of QC data from the reported analyses shows adequate control of contamination and equipment calibration.

Radiometric Disequilibrium

Radiometric disequilibrium refers to the loss or gain of uranium and/or its daughter products (e.g. radon-222, bismuth-214 and radium-226) in the mineralised zone during geologic processes, which can disrupt the equilibrium between the parent isotope and the daughter products. Some historic reports state that closed can assays from Copper Mountain indicated little disequilibrium, however differences between gamma probe data and chemical assay were still observed. From the analysis data received, and comparison with the downhole spectral gamma probe data, it is apparent that disequilibrium has occurred within the Canning deposit. Individual grades are often higher, or lower, than those previously reported by the spectral gamma probe, implying that uranium, or its daughter products, have been mobile in the system since initial deposition. The average ratio of chemical assay intervals to spectral gamma probe assay intervals is ~1.2, indicating uranium content to be biased towards higher grades in the chemical assays, by as much as 20% on average. It is unclear at this stage if the disequilibrium observed results from radon interference or leaching and remobilisation of uranium or radium and other daughter products in the geological environment. Myriad will expand the physical sampling program to submit more samples to the laboratory to account for zones where higher uranium levels might be returned compared to low levels of spectral gamma measurement. Additional high resolution spectral analyses of samples will also be required to determine the specific cause of disequilibrium within the system.

Geological Background

Uranium mineralisation at Copper Mountain occurs in two distinct geologic environments:

• Fracture-controlled uranium mineralisation hosted in Archaean-aged granite, syenite, isolated occurrences along the margins of diabase dikes and in association with meta-sediment inclusions in granite; and

• As disseminations in coarse-grained sandstones and coatings on cobbles and boulders in the Tertiary-aged Teepee Trail Formation at the Arrowhead (Little Mo) mine and other localities.

Uranium mineralisation is thought to have resulted through supergene and hydrothermal enrichment processes. In both cases, the source of the uranium is thought to be the granites of the Owl Creek Mountains.

Historic Estimates of Potential Mineral Endowment

The potential mineral endowment referred to in this news release is based on a 1982 study by Bendix Field Engineering Corporation ("Bendix"), commissioned by the US Department of Energy as reported here. The estimates are historical in nature and do not represent current mineral resource, reserve or exploration target estimates under the category definitions provided by NI 43-101. They represent potential mineral endowments that would require exploration work and drilling to verify. The key assumptions, parameters, and methods used to prepare the historical estimates are described in this document. There are no more recent estimates of this type. A qualified person has not done sufficient work to classify the historical estimates as current mineral resources or mineral reserves. Myriad is not treating the historical estimates as current mineral resources or mineral reserves.

Transaction with Rush Rare Metals Corp. ("Rush")

Myriad is also pleased to provide an update respecting its previously announced merger transaction with Rush (announced here). The parties have completed the majority of their mutual due diligence investigations, and Rush recently informed Myriad that they are finalising work with their independent advisor regarding the proposed transaction. The parties will provide a further update in due course.

Qualified Person

The scientific or technical information in this news release respecting the Company's Copper Mountain Project has been reviewed and approved by George van der Walt, MSc., Pr.Sci.Nat., FGSSA, Myriad's consulting geologist and a Qualified Person ("QP") as defined in National Instrument 43-101 - Standards of Disclosure for Mineral Projects. The Exploration Results reported in this news release have been compiled and verified by the QP. This included personal inspection of core sample intervals, comparison of reported grade interval tables and appropriate QAQC.

This news release contains references to historical estimates. While the content of the source reports is considered to be relevant and reliable, the underlying data, such as original drill logs, sampling, analytical and test data certificates, quality assurance and quality control, is not available for verification. Further work, such as drilling and sampling, will be required to verify or create supplementary information to support the underlying assumptions and conclusions.

About Myriad Uranium Corp.

Myriad Uranium Corp. is a uranium exploration company with an earnable 75% interest in the Copper Mountain Uranium Project in Wyoming, USA. A recent press release discussing the 1982 U.S. Department of Energy assessment of Copper Mountain's uranium endowment can be viewed here. Copper Mountain hosts several known uranium deposits and historic uranium mines, including the Arrowhead Mine which produced 500,000 lbs of U₃O₈. Copper Mountain saw extensive drilling and development by Union Pacific during the late 1970s including the development of a mine plan to fuel a planned fleet of California Edison reactors. Operations ceased in 1980 before mining could commence due to falling uranium prices. Approximately 2,000 boreholes have been drilled at Copper Mountain and the project area has significant exploration upside. Union Pacific is estimated to have spent C$117 million (2024 dollars) exploring and developing Copper Mountain, generating significant historical resource estimates which are detailed here. The Company also recently acquired, subject to completing a geophysical survey this year, a 100% interest in the Red Basin Uranium Project in New Mexico, which has extensive near-surface uranium mineralisation and significant upside potential. Our Crux Investor overview page including recent interviews can be viewed here. The Company's presentation can be viewed here. News releases regarding historical drilling can be viewed here and here. The final news release regarding chemical assays of 2024 Copper Mountain drilling can be viewed here.

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: 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.

APPENDIX 1: Updated Grade Interval Tables

a) Cut-off >1,000 ppm U₃O₈ or GT>0.30 ft% (equivalent to 1,000 ppm over 3 ft / ~1 m)

 
Notes: * Grade intervals corrected to match downhole log intervals.

1) The interval lengths are "down the hole" and may not represent true width intervals as the exact nature of the mineralization distribution has not been determined yet. However, most of the holes were drilled at an inclination of 50 degrees to test a model that indicates steeply dipping mineralisation.

2) eU₃O₈ is the radiometric equivalent U₃O₈ derived from a calibrated total gamma downhole probe.

3) U₃O₈ is the chemical assay of mineralized split core samples or RC cuttings.

4) Core sampling was conducted at 3 feet intervals, adjusted to minimum of 1 foot, where appropriate.

5) Reverse Circulation sampling was conducted at 5 feet intervals.

6) Assay interval depths have been adjusted to spectral gamma probe depths, where appropriate.

7) Intervals were composited above a cut-off grade of 1,000 ppm U₃O₈, with grade below cut-off less than 1 foot being included in the total interval. Internal waste was limited to a maximum of 3 feet.

8) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.

9) "High-grade uranium" is defined by the Company as composite results with >1,000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.

b) Cut-off >500 ppm U₃O₈ or GT>0.15 ft% (equivalent to 500 ppm over 3 ft / ~1 m)

 
Notes: * Grade intervals corrected to match downhole log intervals.

1) The interval lengths are "down the hole" and may not represent true width intervals as the exact nature of the mineralization distribution has not been determined yet. However, most of the holes were drilled at an inclination of 50 degrees to test a model that indicates steeply dipping mineralisation.

2) eU₃O₈ is the radiometric equivalent U₃O₈ derived from a calibrated total gamma downhole probe.

3) U₃O₈ is the chemical assay of mineralized split core samples or RC cuttings.

4) Core sampling was conducted at 3 feet intervals, adjusted to minimum of 1 foot, where appropriate.

5) Reverse Circulation sampling was conducted at 5 feet intervals.

6) Assay interval depths have been adjusted to spectral gamma probe depths, where appropriate.

7) Intervals were composited above a cut-off grade of 500 ppm U₃O₈, with grade below cut-off less than 1 foot being included in the total interval. Internal waste was limited to a maximum of 3 feet.

8) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.

9) "High-grade uranium" is defined by the Company as composite results with >1,000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.

c) Cut-off >200 ppm U₃O₈ or GT>0.06 ft% (equivalent to 200 ppm over 3 ft / ~1 m)

  
Notes: * Grade intervals adjusted to match downhole log intervals.

1) The interval lengths are "down the hole" and may not represent true width intervals as the exact nature of the mineralization distribution has not been determined yet. However, most of the holes were drilled at an inclination of 50 degrees to test a model that indicates steeply dipping mineralisation.

2) eU₃O₈ is the radiometric equivalent U₃O₈ derived from a calibrated total gamma downhole probe.

3) U₃O₈ is the chemical assay of mineralized split core samples or RC cuttings.

2) Core sampling was conducted at 3 feet intervals, adjusted to minimum of 1 foot, where appropriate.

3) Reverse Circulation sampling was conducted at 5 feet intervals.

4) Assay interval depths have been adjusted to spectral gamma probe depths, where appropriate.

5) Intervals were composited above a cut-off grade of 200 ppm U₃O₈, with grade below cut-off less than 1 foot being included in the total interval. Internal waste was limited to a maximum of 3 feet.

6) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.

7) "High-grade uranium" is defined by the Company as composite results with >1,000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.
  

d) Cut-off >100 ppm U₃O₈ or GT>0.03 ft% (equivalent to 100 ppm over 3 ft / ~1 m)