Rouyn-Noranda, Quebec--(ACN Newswire - April 30, 2026) - Radisson Mining Resources Inc. (TSXV: RDS) (OTCQX: RMRDF) ("Radisson" or the "Company") is pleased to announce assay results from sixteen new drill holes completed at its 100%-owned O'Brien Gold Project ("O'Brien" or the "Project") located in the Abitibi region of Québec. Of note, today's results include significant intercepts of high-grade gold in the new pilot hole OB-26-384 at 1.9 kilometres vertical depth, the deepest hole ever drilled at the Project. These results are the latest from the Company's ongoing 140,000-metre step-out drill program and extend the scope of gold mineralization beyond the Company's recent updated March 2026 Mineral Resource Estimate. Highlights include (summarized below, and in Figure 1):

• OB-26-384, the deepest hole ever drilled at the O'Brien Gold Project, intersected 4.54 grams per tonne ("g/t") gold ("Au") over 12.0 metres (core length) including 16.85 g/t Au over 1.0 metre and including 12.87 g/t Au over 1.0 metre and 7.21 g/t Au over 2.0 metres including 9.91 g/t Au over 1.0 metre;

• OB-25-378W2 intersected 5.96 g/t Au over 6.9 metres including 8.77 g/t Au over 3.7 metres and 11.65 g/t Au over 1.5 metres and 8.77 g/t Au over 1.3 metres;

• OB-26-385W1 intersected 20.39 g/t Au over 1.5 metres and 16.61 g/t Au over 1.5 metres;

• OB-26-385 intersected 4.13 g/t Au over 4.7 metres including 15.29 g/t Au over 1.0 metre and 5.55 g/t Au over 1.2 metres;

Matt Manson, President and CEO: "Since late 2024 we have been engaged in an aggressive 140,000-metre program of step-out drilling at the O'Brien Gold Project with the objective of testing the full scope of mineralization down to a 2-kilometre floor. Drill results reported through the course of 2025 and early 2026 confirmed the presence of an increasingly significant, high-grade gold vein system beneath the historic O'Brien mine workings and below the modern mineral resource area. On March 2^nd we published an interim update to the Project's Mineral Resource Estimate with a meaningful 82% increase in Inferred Mineral Resources based on the drilling completed to that date. Now, we are reporting additional high-grade results that extend the scope of mineralization further still. The headline result is from new pilot hole OB-26-384, the deepest drill hole ever completed at the Project, which has returned multiple high-grade intercepts of gold in classic vein settings at 1,900 metres vertical depth, a full 350 metres below the current limit of mineral resources in this area (Figure 1). Overall, seven out of seven holes completed in the central "O'Brien" and "East O'Brien" target areas have returned intercepts with thicknesses and gold grades consistent with the Project's mineral resources, giving an overall success rate of 79% for the step-out drilling completed to date. A fence of nine shallow holes in the lower-priority "Thompson-Cadillac" area have confirmed the extension of the Project's mineralizing system west of the historic mine, albeit at lower average grades. Looking forward, seven drill rigs are active at the Project, with twenty-two additional holes completed or in progress, thirteen of which have returned visible gold intercepts."

Figure 1: Longitudinal Vertical Section and Plan View of Gold Vein Mineralization and Mineral Resources at the O'Brien Gold Project, with Today's Drill Holes Illustrated

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Table 1: Assay Results from Select Drill Holes 

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Notes on Calculation of Drill Intercepts:

The O'Brien Gold Project Mineral Resource Estimate effective January 31, 2026 ("MRE") utilizes a 2.20 g/t Au bottom cutoff, a US$2,500 gold price, a minimum mining width of 1.2 metres, and a 60 g/t Au upper cap on individual assays. Intercepts presented in Table 1 are calculated with a 3.00 g/t Au bottom cut-off. Sample grades are uncapped. True widths, based on depth of intercept and drill hole inclination, are estimated to be 30-80% of core length. Table 3 presents additional drill intercepts calculated with a 1.00 g/t bottom cut-off over a minimum 1.0 metre core length so as to illustrate the frequency and continuity of mineralized intervals within which high-grade gold veins at O'Brien are developed. Drill holes OB-26-388 and 389 at Thompson-Cadillac did not return any intercepts averaging above 1.00 g/t Au. Lithology Codes: PON-S3: Pontiac Sediments; V3-S, V3-N, V3-CEN: Basalt-South, North, Central; S1P, S3P: Conglomerate; POR-S, POR-N: Porphyry South, North; TX: Crystal Tuff; ZFLLC: Larder Lake-Cadillac Fault Zone

Step-Out Drilling at O'Brien

Since the end of 2024, Radisson has been pursuing a program of broad step-outs beneath the historic O'Brien Gold mine and the existing mineral resources designed to test the extent of mineralization at the Project. This drilling is accomplished with pilot holes followed by wedges and directional drilling to maximize drill efficiency. In October 2025, Radisson announced the expansion of the step-out drill program to 140,000 metres employing an eventual eight drill rigs (see Radisson news release dated October 16, 2025). Since this program began, 79% of completed drill holes have intersected gold mineralization with grades and core-lengths consistent with the Project's Mineral Resources, including the results published today (Table 2). Radisson publishes the results of all completed drill holes.

Figure 2: Vertical Section through "Trend #1 with Pilot Hole OB-26-384 at 1.9 kilometres Vertical Depth

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The origin of the step-out drill program was the deep pilot hole OB-24-337, which was the first exploration drill hole located below the former mine workings since mining ended in 1957. This hole intersected 31.24 g/t Au over 8.0 metres, including 242.0 g/t Au over 1.0 metre at approximately 1,500 metres vertical depth (see Radisson news release dated December 16, 2024). Fifteen wedge branches were completed from OB-24-337 delineating up to eight gold-bearing veins over a 250-metre x 700-metre area (see Radisson news release dated February 12, 2026), contributing significant new mineral resources in the March 2026 update. Pilot hole OB-26-384, which is highlighted in today's news release, is the deepest hole ever drilled at the O'Brien Gold Project and has been positioned to test the downward plunge of mineralization in "Trend #1" (Figures 1 and 2). This hole returned (in core lengths) 4.54 g/t Au over 12.0 metres including 16.85 g/t Au over 1.0 metre and also including 12.87 g/t Au over 1.0 metre at 1,900 metres vertical depth, 350 metres beneath the base of the mineral resource area above and approaching the 2-kilometre exploration floor. The observed gold mineralization is within characteristic quartz-sulphide-gold veins and alteration envelops developed within the conglomerate and porphyry units of the Piché Group, consistent with the mineralization observed at higher elevations (Figure 2). This represents a significant potential expansion in the scope of mineralization at the Project. Wedge branches from this new pilot hole are ongoing.

Today's results also include the first assays from pilot hole OB-26-385 and its first wedge branch (385W1) drilled between the OB-24-337 drill pattern and the base of the historic workings at approximately 1,100 metres vertical depth, and the first wedge branches from pilot hole OB-25-378 (378W1 and 378W2) drilled below the 337 pattern at approximately 1,700 metres vertical depth (Figure 1). All of these holes have returned multiple intercepts with high grades over characteristic vein intervals, such as (in core lengths) 20.39 g/t Au over 1.5 metres, 16.61 g/t Au over 1.5 metres, 4.13 g/t Au over 4.7 metres including 15.29 g/t Au over 1.0 metres, 11.65 g/t Au over 1.5 metres and 5.96 g/t Au over 6.9 metres including 8.77 g/t Au over 3.7 metres. These results demonstrate the up-dip and down-dip continuity of this newly delineated vein system, and additional wedge branches in these areas are also ongoing.

Table 2: Drill Results Published for the O'Brien Gold Project since December 2024

Gold Mineralization at O'Brien

Gold mineralizing quartz-sulphide veins at O'Brien occur within a thin band of interlayered mafic volcanic rocks, conglomerates, and porphyritic andesitic sills of the Piché Group occurring in contact with the east-west oriented Larder Lake-Cadillac Break ("LLCB"). Gold, along with pyrite and arsenopyrite, is typically associated with shearing and a pervasive biotite alteration, and developed within multiple Piché Group lithologies and, occasionally, the hanging-wall Pontiac and footwall Cadillac meta-sedimentary rocks.

As mapped at the historic O'Brien mine, and now replicated in the modern drilling, individual veins are generally narrow, ranging from several centimetres up to several metres in thickness and are associated with broader, mineralized alteration envelopes. Multiple veins occur sub-parallel to each other, as well as sub-parallel to the Piché lithologies and the LLCB. Individual veins have well-established lateral continuity, with steeply plunging grade shoots developed over significant lengths. Based on the historic data available, it is clear that the former mine was "high-graded", with mining focussed on a main central stope and parallel veins identified but left undeveloped.

The historic O'Brien mine produced over half a million ounces of gold from such veins and shoots at an average grade exceeding 15 g/t Au and over a vertical extent of at least 1,000 metres. Modern exploration has focussed on delineating well developed vein mineralization to the east of the historic mine, with additional high-grade shoots becoming evident in the exploration data over what has been described as a series of repeating trends (Trend #s 0 to 5).

QA/QC

All drill cores in this campaign are NQ in size. Assays were completed on sawn half-cores, with the second half kept for future reference. Drill core samples are sent to MSALABS's analytical laboratory located in Val-d'Or, Québec, for preparation and gold analysis. The entire sample is dried and crushed (70% passing a 2-millimeter sieve) and split to 500 g. The analysis for gold is performed on an approximately 500 g aliquot using Chrysos PhotonAssay™ technology. Mineralized zones containing visible gold were analyzed to extinction whereby the entire sample is split into multiple jars, each is analysed by PhotonAssay, and the average of the results is used for reporting. Standard reference materials, blank samples and duplicates were inserted for quality assurance and quality control.

MSALABS operates under ISO/IEC 17025 accreditation, utilizing industry-standard QA/QC frameworks for gold analysis. By integrating blanks, duplicates, and CRMs into their workflows, the laboratory adheres to established benchmarks that ensure precise, reliable, and verifiable results.

QP Disclosure

Disclosure of a scientific or technical nature in this news release was prepared under the supervision of Mr. Richard Nieminen, P.Geo, (QC), a geological consultant for Radisson and a Qualified Person for purposes of NI 43-101. Mr. Luke Evans, M.Sc., P.Eng., ing, of SLR Consulting (Canada) Ltd., is the Qualified Person responsible for the preparation of the MRE at O'Brien. Each of Mr. Nieminen and Mr. Evans is independent of Radisson and the O'Brien Gold Project.

Table 3: Detailed Assay Results (see "Notes on Calculation of Drill Intercepts")

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Table 4: Drill Hole Collar Information for Holes contained in this News Release

 

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Notes:

Hole lengths for wedges represent meterage from point of wedge. Drill holes OB-25-377 and 378 were completed in 2025 while their wedge branches were drilled in 2026.

About Radisson Mining

Radisson is a gold exploration company focused on its 100% owned O'Brien Gold Project, located in the Bousquet-Cadillac mining camp along the world-renowned Larder-Lake-Cadillac Break in Abitibi, Québec. A July 2025 PEA described a low cost and high value project with an 11-year mine life and significant upside potential based on the use of existing regional infrastructure. Indicated Mineral Resources are estimated at 0.63 Moz (3.49 Mt at 5.59 g/t Au), with additional Inferred Mineral Resources estimated at 1.69 Moz (10.37 Mt at 5.08 g/t Au). Please see the NI 43-101 "O'Brien Gold Project Technical Report and Preliminary Economic Assessment, Québec, Canada" effective June 27, 2025, Radisson's news release dated March 2, 2026 "With Step-Out Drilling Continuing, Radisson Demonstrates Meaningful Resource Growth at O'Brien with an Updated Mineral Resource Estimate" and other filings made with Canadian securities regulatory authorities available at www.sedarplus.ca for further details and assumptions relating to the O'Brien Gold Project. For more information on Radisson, visit our website at www.radissonmining.com or contact:

Forward-Looking Statements

This news release contains "forward-looking information" within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections, and interpretations as at the date of this news release. Forward-looking statements including, but are not limited to, statements with respect to the ability to execute the Company's plans relating to the O'Brien Gold Project as set out in the Preliminary Economic Assessment; the Company's ability to complete its planned exploration and development programs; the absence of adverse conditions at the O'Brien Gold Project; the absence of unforeseen operational delays; the absence of material delays in obtaining necessary permits; the price of gold remaining at levels that render the O'Brien Gold Project profitable; the Company's ability to continue raising necessary capital to finance its operations; the ability to realize on the mineral resource and mineral reserve estimates; assumptions regarding present and future business strategies; local and global geopolitical and economic conditions and the environment in which the Company operates and will operate in the future; planned and ongoing drilling; the significance of drill results; the ability to continue drilling; the impact of drilling on the definition of any resource; and the ability to incorporate new drilling in an updated technical report and resource modelling; the Company's ability to grow the O'Brien Gold Project; and the ability to convert inferred mineral resources to indicated mineral resources.

Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "interpreted", "management's view", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. Except for statements of historical fact relating to the Company, certain information contained herein constitutes forward-looking statements Forward-looking information is based on estimates of management of the Company, at the time it was made, involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the companies to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others; the risk that the O'Brien Gold Project will never reach the production stage (including due to a lack of financing); the Company's capital requirements and access to funding; changes in legislation, regulations and accounting standards to which the Company is subject, including environmental, health and safety standards, and the impact of such legislation, regulations and standards on the Company's activities; price volatility and availability of commodities; instability in the global financial system; the effects of high inflation, such as higher commodity prices; the risk of any future litigation against the Company; changes in project parameters and/or economic assessments as plans continue to be refined; the risk that actual costs may exceed estimated costs; geological, mining and exploration technical problems; failure of plant, equipment or processes to operate as anticipated; accidents, labour disputes and other risks of the mining industry; delays in obtaining governmental approvals or financing; risks relating to the drill results at O'Brien; the significance of drill results; and the ability of drill results to accurately predict mineralization. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, the parties cannot assure shareholders and prospective purchasers of securities that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither the Company nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. The Company believes that this forward-looking information is based on reasonable assumptions, but no assurance can be given that these expectations will prove to be correct and such forward-looking statements included in this press release should not be unduly relied upon. The Company does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law. These statements speak only as of the date of this news release.

Please refer to the "Risks and Uncertainties Related to Exploration" and the "Risks Related to Financing and Development" sections of the Company's Management's Discussion and Analysis dated April 23, 2026 for the year ended December 31, 2025 available electronically on SEDAR+ at www.sedarplus.ca. All forward looking statements contained in this press release are expressly qualified by this cautionary statement.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.

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