Myriad Uranium Reports Final Chemical Assays from Copper Mountain. Grades Up to 60% Higher Than Probe Equivalents, with Positive Implications for Scale and Scope of the Project. Plan of Operations Application Submitted to Drill High Priority Prospects

Vancouver, British Columbia--(Newsfile Corp. - June 11, 2025) - Myriad Uranium Corp. (CSE: M) (OTCQB: MYRUF) (FSE: C3Q) is pleased to report chemical assay results from the final six boreholes drilled in late 2024 at the Copper Mountain Uranium Project in Wyoming (Figure 1).

These results and the complete set of confirmed chemical assay grades (U₃O₈) across all 34 holes drilled late 2024 have been compared against previously reported equivalent spectral gamma probe grades (eU₃O₈) and confirm extensive high-grade uranium mineralisation at the Canning Deposit. Myriad's drilling program prioritized Canning due to Union Pacific's 1979 mine plan, which identified it as the largest mineralized area and the central pit of an initial six pit mining plan. Verification of historical work in this area has therefore been a priority.

Confirmed U₃O₈ grades are on average significantly higher than eU₃O₈ probe grades. The fact that confirmed individual U₃O₈ grades are higher, and sometimes lower, than corresponding eU₃O₈ grades, indicates secular disequilibrium is present in the system. The gamma probe tends to especially underestimate higher grades.

Across the 34 assayed boreholes to date, confirmed U₃O₈ grades are on average:

• 60% higher at a 1,000 ppm cut-off
• 50% higher at 500 ppm cut-off
• 20% higher at 200 ppm cut-off

Many intervals with initially low or near-zero probe readings have been confirmed as mineralized by chemical assay. Notably, the deepest intercept (CAN0034, 1,489.45-1,491.25 ft) returned 832.5 ppm U₃O₈, a 242% increase over its equivalent probe grade. Therefore, more samples from the drilling campaign are being submitted for laboratory testing, and chemical assay will become the primary reporting method for Copper Mountain going forward.

Thomas Lamb, the CEO of Myriad, stated: "Based on the results of our initial drill campaign, we can preliminarily assert several positive findings. First, our assays suggest the high end of Union Pacific's historical estimate of 15-30 million pounds U₃O₈ across six deposits to a maximum depth of 600 feet is more accurate [see "Historical Estimates" disclaimer below]. Union's decision to depend on DFN grade data was overly conservative, as a number of experts had suspected. Second, our deeper intercepts may indicate new, previously unaccounted pounds. Third, these preliminary findings of deeper mineralisation, along with our higher grade mineralization's association with faults and fractures in basement granite and amphibolite schists (similar to Beaver Lodge in Athabasca) support statements in Neutron Energy internal documents from 2006-2010 that Copper Mountain's potential is "several hundred million pounds" and that "new genetic models suggest a high chance for discovery of world-class deposits in both hard rock and sandstone."

George van der Walt, Myriad's consulting geologist and technical advisor, commented: "It is good to see that the last set of final results continue to hold up to expectations. We now aim to fill gaps in the physical sampling, which has commenced."

Updated significant chemical assay intervals with a GT >0.15 ft% (equivalent to 500 ppm over 3 feet), and their equivalent spectral gamma probe intervals are provided in Table 1 below. Note that Appendix 1 provides all grade intervals at (a) 1,000 ppm (0.10%) U₃O₈ cut-off, 500 ppm (0.05%) U₃O₈ cut-off and (b) 200 ppm (0.02%) U₃O₈ cut-off.

Table 1: Significant intervals from chemical assay and their equivalent spectral gamma probe intervals (GT >0.15 ft% or 500 ppm U₃O₈ over 3 feet)

Notes:

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, according to the drilling procedure.
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.
8) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.
9) "High-grade uranium" is defined by the Company as composite results with >1000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.

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.

Table 2: Collar details for boreholes completed by Myriad

Deeper Mineralisation

One of the aims of the drilling program was to test for deeper mineralisation, below the level that Union Pacific had conducted their drilling (around 600 feet on average). The last borehole, CAN0034, was drilled to a final depth of 1,556 feet and intersected mineralisation between 1,489.45 and 1,491.25 (1.80 feet). Where the equivalent gamma grade from the spectral gamma probe indicated an average grade of 343.8 ppm eU₃O₈, the chemical assay returned an average grade of 832.5 ppm U₃O₈ over the equivalent interval.

This outcome is encouraging for the potential of deeper mineralisation at Canning and elsewhere and needs to be investigated further. It also illustrates that the actual chemical grade and the equivalent gamma grades can vary significantly.

Table 3: Deeper interval comparison in borehole CAN0034

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 allow, to obtain downhole structural information. Borehole paths are being 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.

Drill Permits

The Copper Mountain project has 50 holes remaining under its current Drilling Notification permit, all located at Canning. The Company and its partner Rush Rare Metals Corp. have applied for a large-scale Plan of Operations permit across the entire project area. If approved, this permit will increase the number of permitted boreholes to 70, enabling the drilling of high priority prospects such as Lucky Cliff, where historical intercepts include 85 feet at 0.12% U₃O₈. Applications to amend the Plan of Operations will then be made from time to time as exploration advances.

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.

Historical Estimates

While Myriad has determined that the historical estimates described in this news release are relevant to the Copper Mountain Project Area and are reasonably reliable given the authors and circumstances of their preparation, and are suitable for public disclosure, readers are cautioned to not place undue reliance on these historical estimates as an indicator of current mineral resources or mineral reserves at the Project Area. A qualified person (as defined under NI 43-101) has not done sufficient work to classify any of the historical estimates as current mineral resources or mineral reserves, and Myriad is not treating the historical estimates as a current mineral resource or mineral reserve. 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. Furthermore, the estimates are decades old and based on drilling data for which the logs are, as of yet, predominantly unavailable. The historical resource estimates, therefore, should not be unduly relied upon.

Inherent limitations of the historical estimates include that the nature of the mineralisation (fracture hosted) makes estimation from drill data less reliable than other deposit types (e.g. those that are thick and uniform). From Myriad's viewpoint, limitations include that the Company has not been able to verify the data itself and that the estimate 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.

In order to verify the historical estimates and potentially re-state them as current resources, a program of digitization of available data is required. This must be followed by re-logging and/or re-drilling to generate new data to the extent necessary that it is comparable with the original data, or 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 or technical information in this news release respecting the Company's Copper Mountain Project has been approved by George van der Walt, MSc., Pr.Sci.Nat., FGSSA, a Qualified Person as defined in National Instrument 43-101 - Standards of Disclosure for Mineral Projects. Mr. van der Walt is employed by The MSA Group (Pty) Ltd (MSA), a leading geological consultancy providing services to the minerals industry, based in Johannesburg, South Africa. He has more than 20 years industry experience and sufficient relevant experience in the type and style of mineralisation to report on exploration results.

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. Copper Mountain hosts several known uranium deposits and historic uranium mines, including the Arrowhead Mine which produced 500,000 lbs of eU₃O₈. 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 a near-surface historical resource (non-43-101) at grades from 1,700 to 3,100 ppm with significant upside potential. The announcement regarding the acquisition can be viewed here and a subsequent announcement regarding an expansion of the Company's acreage to encompass 800 of 1,050 historical boreholes in the basin can be viewed here. 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.

Myriad also has a 50% interest in the Millen Mountain Property in Nova Scotia, Canada, with the other 50% held by Probe Gold Inc. 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: Grade Interval Tables

a) Intervals with GT>0.3 (equivalent to >1,000 ppm U₃O₈ over >3 feet)

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, according to the drilling procedure.
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.
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) Intervals with GT>0.15 (equivalent to >500 ppm U₃O₈ over >3 feet)

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, according to the drilling procedure.
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.
8) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.
9) "High-grade uranium" is defined by the Company as composite results with >1000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.

c) Intervals with GT>0.06 (equivalent to >200 ppm U₃O₈ over >3 feet)

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.
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, according to the drilling procedure.
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.
6) Abbreviations: DD = Diamond Drill, RC = Reverse Circulation.
7) "High-grade uranium" is defined by the Company as composite results with >1000 ppm U₃O₈ and no greater than 1-foot continuous internal dilution.