Radisson Mining Resources Inc. (TSX-V: RDS) (OTCQX: RMRDF) is pleased to announce the results of eight new drill holes recently completed at its 100%-owned O’Brien Gold Project located in the Abitibi region of Québec. The eight holes form part of two clusters of drill holes based on pilot holes and wedge branches that are serving to delineate an important system of high-grade mineralization in multiple quartz-sulphide-gold veins over a now 1,000-metre vertical interval beneath the former O’Brien Gold Mine. These results are the latest from the Company’s ongoing 140,000-metre step-out drill program designed to test the full scope of gold mineralization at the Project.

All eight drill holes reported today returned significant gold mineralization. Highlights (Figure 1 and Table 1) include:

• OB-26-385W5 intersected 68.24 grams per tonne gold over 6.20 metres (core lengths) including 384.01 g/t Au over 1.0 metre and including 28.68 g/t Au over 1.0 metre (residual intercept grade of 2.48 g/t Au);
• OB-26-385W8 intersected 27.27 g/t Au over 3.3 metres including 72.40 g/t Au over 1.2 metres (residual intercept grade of 1.49 g/t Au), and 3.90 g/t Au over 9.3 metres including 6.10 g/t Au over 2.0 metres and including 5.78 g/t Au over 1.2 metres (residual intercept grade of 2.81 g/t Au), and 8.35 g/t Au over 4.0 metres including 16.10 g/t Au over 1.5 metres (residual intercept grade of 3.7 g/t Au);
• OB-25-378W4 intersected 8.14 g/t Au over 5.50 metres including 11.52 g/t Au over 3.70 metres (residual intercept grade of 1.19 g/t Au);
• OB-26-385W7 intersected 18.13 g/t Au over 2.0 metres including 34.91 g/t Au over 1.0 metre (residual intercept grade of 1.35 g/t Au); and
• OB-25-378W5 intersected 3.90 g/t Au over 9.3 metres including 16.84 g/t Au over 1.4 metres (residual intercept grade of 1.60 g/t Au) and 4.00 g/t Au over 4.60 metres.

Matt Manson, President and CEO: “Since the beginning of our deep step-out drilling program at O’Brien in late 2024, we have enjoyed consistent success in expanding the scope of mineralization beyond the former mine and the historical mineral resources. Of the 128 drill holes completed during this period,106 have returned drill intercepts with grades and thicknesses consistent with our mineral resources. This is an impressive 83% “hit” rate (Table 2), and we report every hole completed. We continue to see a consistent pattern of high-grade quartz-sulphide-gold veins within broader, mineralized alteration halos. These mineralized zones form parallel vein packages within the host Piché Group rocks, with good continuity across adjacent drill holes and over significant distances. The two clusters of new drill results reported today are delineating the important “O’Brien Mine East” trend at its top, immediately below the former mine workings, and extending it downwards at up to 2 kilometres vertical depth. In our reporting of drill results, as with today’s news, we show the grade of the full interval across the mineralized zone (in core lengths at a 1 g/t Au bottom cut-off) and the “including” interval representing the high-grade quartz-sulphide-gold vein within the zone. The intercept’s residual grade, which represents grade in the alteration halo, is typically between 1 g/t Au and 4 g/t Au. These patterns are all demonstrated reliably in today’s results. O’Brien is clearly a large scale and increasingly predictable gold mineralizing system. Drilling is ongoing with eight rigs active at the Project.”

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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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. 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. 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 below and to the east of the historic mine. Based on the historic data available, it is clear that the former mine was “high-graded”, with mining focused on a main central stope and parallel veins identified but left undeveloped.

Figure 2: Visible gold in OB-26-385W5 yielding 384.01 g/t Au over 1.0 metre between 1,514.2 metres and 1,515.2 metres, within a broader intercept averaging 68.24 g/t Au over 6.2 Metres between 1,511 metres and 1,517.2 metres

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Table 1: Assay Results Calculated at a 3 g/t Au Bottom Cut-Off from Drill Holes Published Today

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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 cut-off, 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 Au 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.

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 eight drill rigs (see Radisson news release dated October 16, 2025).

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 m 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 by 700-metre area in what is referred to as “O’Brien Mine East” (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 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. Drilling has recently confirmed the extension of the “Trend 1” zone of mineralization to 1.9 kilometres vertical depth (see Radisson news release dated April 30, 2026).

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. Positive drill results have recently been reported from the “Trend 1-Trend 2 Gap” at approximately 500 and 1,000 metres vertical depth, demonstrating continuity of mineralization across what were previously thought to be discrete mineralization trends (see Radisson news release dated June 1, 2026 and September 2, 2026).

The eight new drill holes at the Project reported today continue to demonstrate the very high incidence of intercepts with grades and thicknesses consistent with the Project’s mineral resources (“hits”, per Table 2). This now stands at 83% of all drill holes completed to date, an impressive result for a step-out drill program specifically targeting non-resource areas (Figure 4). Mineralization remains open in every direction, with clear opportunities to expand the quantity of new mineral resources, in particular by drilling at depth.

Figure 3: Vertical Section Through “O’Brien Mine East” with Today’s New Drill Results

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Figure 4: Deep Step-Out Drill Holes Completed and/or Published by the Company Since March 2026

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Table 2: Drill Results Published for the O’Brien Gold Project Since December 2024

Table 3: Detailed Assay Results Calculated at a 1 g/t Au Bottom Cut-Off from Drill Holes Published Today (see “Notes on Calculation of Drill Intercepts”)

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Table 4: Drill Hole Collar Information for Drill Holes Published Today

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Notes: Hole lengths for wedges represent meterage from point of wedge. Collar position is reported for pilot hole.

QA/QC

All drill core in this campaign is NQ in size. Assays were completed on sawn half-core, with the second half retained in the core box for future reference. Geologists mark cut lines on the core perpendicular to the foliation. The half on the right side of the saw blade is bagged for the laboratory and the left half is retained as reference. Sample bags are sealed, placed in rice sacks, plastic-wrapped on pallets, and held in a secure facility until pick-up by the laboratory’s dedicated truck.

Samples are delivered to MSALABS’ analytical laboratory 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. Gold analysis is performed on an approximately 500 g aliquot (a single jar) using Chrysos PhotonAssay technology. Mineralized zones containing visible gold, plus additional intervals selected at the discretion of the logging geologist, are analyzed to extinction, whereby the entire sample is split into multiple ~500 g jars, each jar is analyzed by PhotonAssay, and the weighted average of the results is used for reporting. A one-metre sample typically requires five jars.

Certified reference materials, blank samples, and reject duplicates are inserted for quality assurance and quality control. Either a CRM, a blank, or a duplicate is inserted during regular sampling at a rate of 1 per 25 samples, with the insertion rate increased for intervals selected for assay to extinction. Four different CRMs are in use with an appropriate range of certified grades suited for O’Brien mineralization. Jars of CRM material are stored at the laboratory and inserted into the sample stream as directed by Radisson. The CRMs were selected by Radisson in accordance with Chrysos Corporation’s best-practice guidelines for PhotonAssay. Blanks consist of commercially obtained crushed quartzite known to be barren of gold. Samples returning results greater than 1 g/t Au are also fire assayed.

MSALABS operates under ISO/IEC 17025 accreditation, utilizing industry-standard QA/QC frameworks for gold analysis. Through the integration of blanks, duplicates, and CRMs into its workflow, 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: