Rouyn-Noranda, Quebec--(Newsfile Corp. - June 1, 2026) - Radisson Mining Resources Inc. (TSXV: RDS) (OTCQX: RMRDF) ("Radisson" or the "Company") is pleased to announce new assay results from its 100%-owned O'Brien Gold Project ("O'Brien" or the "Project") located in the Abitibi region of Québec. Today's results are from two pilot holes and five associated wedge branches targeting the "Trend 1-Trend 2 Gap", an area of little previous drilling extending over an approximate 800 metre vertical extent in the central portion of the Project. Six of the seven drill holes have returned significant intercepts of high-grade gold mineralization, with important implications for future mineral resources and mining continuity. These results are the latest from the Company's ongoing 140,000-metre step-out drill program and continue to extend the scope of gold mineralization beyond the Company's recent updated March 2026 Mineral Resource Estimate ("MRE"). Highlights (Figure 1 and Table 1) include:
OB-26-387W2 intersected 7.57 grams per tonne ("g/t") gold ("Au") over 9.7 metres (core length) including 52.75 g/t Au over 1.1 metre;
OB-26-386W1 intersected 3.43 g/t Au over 13.4 metres including 8.63 g/t Au over 1.0 metres and including 10.26 g/t Au over 1.0 metres and including 8.24 g/t Au over 1.0 metres;
OB-26-387W3 intersected 66.93 g/t Au over 1.0 metres and 24.97 g/t Au over 1.0 metres;
OB-26-387W4 intersected 69.05 g/t Au over 1.0 metres and 5.28 g/t Au over 1.0 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. We recently announced plans to extend our exploration ambition further, with new deep drilling and directional wedging to a depth of 2.5-kilometres. At the same time, we are targeting under-explored areas at shallower depths. Previous drilling at O'Brien has defined steeply plunging mineralization "Trends" separated by "Gaps" (Figure 1). This pattern of mineralization defines the character of our mineral resource block model and influences our exploration targeting. An outstanding question has been whether these Trends reflect actual, large-scale structural controls on mineralization or are simply a feature of insufficient drilling. Today's results, targeting the important "Trend 1-Trend 2 Gap" which has a top to bottom vertical extent of 800 metres (Figure 2), support our belief that, in this area at least, mineralization is laterally continuous. This has important implications for mineral resource updates in the centre of the Project, the character of the Project's distribution of mineralization, stope continuity in mine design, and the location of infrastructure such as drifts and ramps in a future potential mine. Six of seven drill holes completed in this area returned intercepts with thicknesses and grades consistent with the Project's mineral resources, maintaining the high success rate of the ongoing step-out drill program. Results from additional directional wedges in the Trend 1-Trend 2 Gap, and from additional deeper drilling below the historical mine workings and the base of the current mineral resources, are expected shortly."
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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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 gold mineralization at the Project. This drilling is accomplished with pilot holes followed by wedges and directional drilling to maximize drill efficiency and minimize costs. 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).
Figure 2: The "Trend 1-Trend 2 Gap" Illustrated on the Basis of the March 2026 MRE (left) and the July 2025 PEA Mine Design (Right). This Graphic Also Illustrates the Growth in the Project's MRE since the July 2025 PEA was Completed.
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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 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. Lithology Codes: PON-S3: Pontiac Sediments; V3-S, V3-N, V3-CEN: Basalt-South, North, Central; S1P, S3P: Conglomerate and Greywackes; POR-S, POR-N: Porphyry South, North; TX: Crystal Tuff; ZFLLC: Larder Lake-Cadillac Fault Zone
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). In March 2026, Radisson published an interim update in the Project's mineral resources, showing meaningful growth based on the on-going drilling (see Radisson news release dated March 2, 2026).
The focus of the step-out drill program today has been the extension of mineralization at depth, with an exploration floor of 2 kilometres depth, and recently announced plans to extend this drilling to 2.5 kilometres depth (see Radisson news release dated May 28, 2026). Given the character of neighbouring gold deposits and the wealth of mining infrastructure within or close to the O'Brien Gold Project, Radisson believes that significant exploration potential exists to these depths, and such mineralization might reasonably be expected to be developed.
Figure 3: Vertical Section Through the "Trend 1-Trend 2 Gap" with Today's New Drill Results
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In addition to the progressively deeper drilling, the 140,000-metre program includes targeting of areas within the O'Brien geological model that have not previously been tested and offer the potential for additional mineral resources at shallower depths. As exploration drilling at O'Brien has progressed over the last several years, high-grade intercepts and vein delineations have typically been followed up with additional drilling on steep east plunging trends. This is consistent with the observation of steeply plunging high-grade shoots in the historical O'Brien mine, from surface trenching, and from the orientation of grade trends in the MRE. This exploration strategy has resulted in a number of large-scale mineralization "Trends 0 to 5" being delineated, with intervening "gaps". These gaps are typically defined by a lack of drilling rather than a lack of mineralization. Significant gaps include between the former mine and "Trend 0", and a gap of 800 metres vertical extent between "Trends 1 and 2" (Figures 1 and 2).
Pilot holes OB-26-386 and OB-26-387 were established to target the Trend 1-Trend 2 Gap at approximately 500 and 1,000 metres vertical depth (Figure 3). Multiple directional wedge branches were established from each pilot hole. Today's results from the two pilot holes and the 5 directional wedges completed to date have all returned intercepts of gold mineralization in the characteristic quartz-sulphide-gold veins and alteration envelops developed within the conglomerate, porphyry and volcanic units of the Piché Group. Six of the seven returned intercepts with grades and thicknesses consistent with the Project's mineral resources. Drillhole OB-26-386W1 returned a thick 13.4-metre (core length) intercept averaging 3.43 g/t Au and including three separate 1-metre vein intervals grading 8.63 g/t Au, 10.26 g/t Au and 8.24 g/t Au respectively. Drill hole OB-26-387W2 also returned a thick zone of alteration grading 7.57 g/t Au over 9.7 metres, including a vein interval grading 52.75 g/t Au over 1.1 metres. Drill holes OB-26-387W3 and OB-26-387W4 multiple 1-metre vein intercepts with grades of 66.93 g/t Au, 24.97 g/t Au, 69.05 g/t Au and 5.28 g/t Au (Table 1, Figures 1 and 3).
The implication of these results is that continuity of mineralization at O'Brien, which is well established vertically in the drill data and from the historic mine, can also be established laterally between what were previously thought to be discrete mineralization trends. In addition, the presence of a gap in the mineral resource block model between Trends 1 and 2 drives a gap between mining areas and mine infrastructure planning, as was demonstrated in the mine design contained within Radisson's July 2025 Preliminary Economic Assessment ("PEA") for the Project (Figure 2). Additional mineral resources in these under-drilled gaps will also benefit the density of mineralization at the Project, which is a common measure of economic viability and capital efficiency in underground mine design.
In more general terms, the observation of six holes out of seven returning high-grade intercepts with grade and thicknesses consistent with the Project's mineral resources ("hits", per Table 2) from drill holes targeting non-resource areas is another example of the high-rate of success of the current step-out drill program at O'Brien, and the extent of the O'Brien gold mineralizing system (Figure 4).
Table 2: Drill Results Published for the O'Brien Gold Project Since December 2024
| Date of Publication | Total Number of Drill Holes | Drill Holes with Intercepts >+3g/t | Success Rate (%) |
| June 1, 2026 | 7 | 6 | 86% |
| April 30, 2026-O'Brien | 7 | 7 | 100% |
| April 30, 2026-Thompson-Cadillac | 9 | 2 | 22% |
| January 27, 2026 | 7 | 7 | 100% |
| January 6, 2026 | 6 | 5 | 83% |
| October 28, 2025 | 15 | 13 | 87% |
| September 8, 2025 | 15 | 13 | 87% |
| July 16, 2025 | 14 | 11 | 79% |
| April 2, 2025 | 3 | 3 | 100% |
| February 26, 2025 | 20 | 15 | 75% |
| December 16, 2024 | 1 | 1 | 100% |
| Total | 104 | 83 | 80% |
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 within a series of repeating trends (Trend s 0 to 5).
Figure 4: Deep Step-Out Drill Holes Completed and/or Published by the Company Since March 2026
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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.
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-millimetre 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.
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:
Matt Manson
President and CEO
416.618.5885
mmanson@radissonmining.com
Kristina Pillon
Manager, Investor Relations
604.908.1695
kpillon@radissonmining.com
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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Source: Radisson Mining Resources
