Rouyn-Noranda, Quebec--(Newsfile Corp. - March 2, 2026) - Radisson Mining Resources Inc. (TSXV: RDS) (OTCQB: RMRDF) ("Radisson" or the "Company") is pleased to report an updated Mineral Resource Estimate ("MRE") at its 100%-owned O'Brien Gold Project ("O'Brien" or the "Project") located in the Abitibi region of Québec. The Company is currently undertaking a fully-funded 140,000-metre step-out drill program at the Project with the objective of determining the scope of mineralization to a depth of 2 kilometres. This program commenced in 2025 and is expected to continue through the first half of 2027. Today's updated MRE is an interim report that demonstrates the impact of recent drilling successes completed as of December 31, 2025. Highlights include:

• 82% increase in Inferred Mineral Resources from step-out drilling intersecting new mineralization, with 1.69 million ounces ("Moz") in 10.37 million tonnes ("Mt") at 5.08 grams per tonne ("g/t") gold ("Au");

• 8% increase in Indicated Mineral Resources with 0.63 Moz in 3.49 Mt at 5.59 g/t Au;

• Estimated using US$2,500/oz Au and 2.2 g/t Au cut-off, with a refined geological model and capping strategy, establishing the go-forward basis for future, modern mine development.

Matt Manson, President and CEO: "Today we report the first of several planned, step-by-step updates to the MRE at the O'Brien Gold Project, quantifying the impact of our recent drilling success and establishing a clear foundation for future, modern mine development. With just 25% of our 140,000 metre step-out drill program completed, the new vein mineralization delineated beneath the historic mine workings and the previous mineral resource volume (Radisson news release dated February 12, 2026) has resulted in an 82% increase in the quantity of Inferred Mineral Resources, now 1.69 Moz (10.37 Mt at 5.08 g/t Au). At the same time, we have refined the estimate of Indicated Mineral Resources, incorporating more tonnes at a lower average grade for an 8% increase in contained ounces, now 0.63 Moz (3.49 Mt at 5.59 g/t Au). Our estimates utilize a 2.2 g/t Au cut-off at a reasonable gold price assumption of US$2,500/oz."

"The former O'Brien Mine was known for high-grade ore-shoots mined in small volumes. Mining ended in 1957 with the gold price at US$35/oz. Significant volumes of mineralized vein material, below what we believe to have been a 7 g/t to 8 g/t Au cut-off, were left untouched. Now, we are presenting the Project as it should be viewed for future development: not as a bespoke deposit of extreme grade and limited scale, but as an extensive Abitibi vein deposit with a substantial inventory of mineralized material amenable to modern mechanized mining at higher throughput."

"Our step-out drill campaign at O'Brien is ongoing with up to eight rigs. We expect to complete 72,500 metres in 2026 and 32,500 metres in the first half of 2027. This is in addition to the meterage supporting today's updated MRE. The vein mineralization system we have been intersecting is open at depth. In fact, since our step-out drilling began in the fall of 2024, we have been seeing an impressive 84% success rate in intercepting classic O'Brien quartz-sulphide-gold veins with grades and thicknesses consistent with today's updated MRE. Looking to a 2-kilometre exploration floor, we believe an appropriate Exploration Target at O'Brien is another 5 Mt to 10 Mt at grades of between 4.0 g/t and 6.0 g/t Au containing 0.6 Moz to 2.0 Moz. We expect to complete further step-by-step updates to the MRE as our drilling progresses."

Cautionary statement: Readers are cautioned Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. The estimate of mineral resources may be materially affected by environmental, permitting, legal, title, socio-political, marketing, or other relevant issues including risks set forth in Radisson's filings made with Canadian securities regulatory authorities. The potential quantity and grade of an Exploration Target is conceptual in nature, there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the target being delineated as a mineral resource.

A video presentation of today's news by Matt Manson can be found at https://www.youtube.com/watch?v=5IZwSSYbO70.

Mineral Resource Estimate (effective January 31, 2026)

The MRE is based on 428,440 metres of drilling completed to the end of December 31, 2025, and has been authored by SLR Consulting (Canada) Ltd. ("SLR"). The estimate utilizes a 2.2 g/t Au cut-off at US$2,500/oz and makes certain assumptions on mining and processing costs, currency exchange rate, and metallurgical recovery (Table 1 and Figure 1). A wireframe vein model prepared by Radisson and reviewed by SLR constrains the estimate and applies a minimum width of 1.2 metres. Individual assays are capped at 60 g/t Au prior to compositing to full width of the veins, and the block model utilizes 5 by 2 by 5 metre blocks consistent with recent mine design studies.

Table 1: Mineral Resource Estimate, Effective January 31, 2026

An MRE for the Project was previously published in March 2023 (Radisson news release dated March 2, 2023) based on 325,509 metres of drilling completed to the end of 2022. Indicated Mineral Resources (effective March 2, 2023) were estimated at 0.50 Moz (1.52 Mt at 10.26 g/t Au) with additional Inferred Mineral Resources of 0.45 Moz (1.60 Mt at 8.66 g/t Au). The 2023 study applied a 4.5 g/t Au cut-off at US$1,600/oz Au.

In July 2025, Radisson published a Preliminary Economic Assessment ("PEA") for the Project that utilized the 2023 estimate re-blocked by SLR in the Z-direction from 10 metres to 5 metres to allow for more flexible underground mine design. A cut-off of 2.2 g/t Au at US$2,000/oz Au and an updated set of economic criteria were applied in the re-blocking exercise consistent with the parameters used for the optimization of the PEA's underground mine schedule. No other changes were made. Indicated Mineral Resources (effective May 6, 2025) were estimated at 0.58 Moz (2.20 Mt at 8.22 g/t Au) with additional Inferred Mineral Resources of 0.93 Moz (6.67 Mt at 4.35 g/t Au).

The updated MRE released today benefits from 66,387 metres of additional drilling in 122 drill holes conducted between 2023 and 2025, which is the most significant factor in the increase of Inferred Mineral Resources (Figure 2). Radisson has also validated an additional 36,544 meters of historic drilling. The updated MRE utilizes similar estimation parameters to previously, but a more restrictive approach to capping. In the March 2023 estimate, and as incorporated in the re-blocked May 2025

Figure 1: Block Models for the Mineral Resource Estimates Effective May 6, 2025 (Top) with Recently Published Drill Results and the Updated MRE Effective January 31, 2026 (Bottom) 

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estimate, capping at 40 g/t Au was applied to the full-length composites. In the updated MRE, capping has been applied at 60 g/t Au to the underlying assays prior to compositing. This has the effect of reducing the average grade by approximately 12%, and in the opinion of Radisson and SLR is an appropriate approach to a narrow high-grade vein deposit such as O'Brien.

Figure 2: 3D View of Block Model by Resource Classification (Left) and Gold Grade (Right) Illustrating Volume Utilized in the Previous May 2025 MRE 

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Compared to previous estimates, the aggregate impact on the Indicated Mineral Resources of the new drilling, the 2.2 g/t Au cut-off, and the updated capping strategy has been to add more tonnes at a lower average grade for an overall increase in contained ounces. The aggregate impact of these three factors on the Inferred Mineral Resources has been the addition of more tonnes at a higher average grade for an overall increase in contained ounces. Indicated Mineral Resources have increased by 8% to 0.63 Moz, based on an increase in tonnes of 58% to 3.49 Mt and a decrease in grade of 32% to 5.59 g/t Au. Inferred Mineral Resources have increased by 82% to 1.69 Moz, based on an increase in tonnage of 55% to 10.37 Mt and an increase in grade of 17% to 5.08 g/t Au.

O'Brien's system of Quartz-Sulphide-Gold vein mineralization remains open to depth across a broad front beneath the historic mine workings and the updated MRE. The potential continuation of this mineralization to a 2 kilometres depth defines an Exploration Target of an additional 5 Mt to 10 Mt at grades of between 4.0 g/t and 6.0 g/t Au containing 0.6 Moz to 2.0 Moz. The potential quantity and grade of an Exploration Target is conceptual in nature, there has been insufficient exploration to define a mineral resource and it is uncertain if further exploration will result in the target being delineated as a mineral resource.

Table 2: Sensitivities of the Mineral Resource Estimate Based on Cut-Off

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A New Vision for the O'Brien Gold Project

The historic O'Brien mine produced over half a million ounces of gold at an average grade exceeding 15 g/t Au. It is clear that the former mine was "high-graded", with manual mining methods applied to the highest-grade veins and ore shoots at an estimated cut-off grade of 7 g/t to 8 g/t Au. Parallel but lower-grade mineralized zones, which would be well above an economic cut-off grade today, were left unmined.

The updated MRE does not incorporate any mineral resources potentially remaining in the former mine. However, in applying the lower grade cut-off of 2.2 g/t Au based on a gold-price estimate of US$2,500, the new estimate captures the overall volume attributes of the O'Brien mineralizing system, with more tonnes and more ounces at a lower average grade. This has the benefit of improving the continuity of mineralization for future mine planning, with larger stopes and more development headings supporting a higher potential mining rate. The Project has existing mining infrastructure to support such a vision, such as a shaft in the former mine extending to a 1,000 metres depth and multiple mills in the region with significant future capacity.

Table 2 illustrates sensitivities on Indicated and Inferred Mineral Resources and the MRE block model based on cut-off grade. These are:

• a) 8.0 g/t Au (US$700/oz) representing the former mine,

• b) 4.5 g/t Au (US$1,250/oz) representing the MRE effective March 2, 2023,

• c) 2.2 g/t Au (US$2,500/oz) representing the updated MRE, and

• d) 1.5 g/t Au (US$3,800/oz) representing the recent long-term consensus price of gold.

The comparison clearly indicates the relationship between volume and grade based on cut-off, the directionality of steeply-plunging grade shoots at O'Brien, and the increased continuity of mineralization achieved at progressively lower cut-offs.

Gold Mineralization at O'Brien and Step-Out Drill Program

Gold mineralization at O'Brien occurs within quartz-sulphide veins developed primarily within the interlayered mafic volcanic rocks, conglomerates, and porphyritic andesitic sills of the Piché Group occurring in contact with the regionally significant Larder Lake-Cadillac Break ("LLCB"). Individual veins are generally narrow, ranging from several centimetres up to several metres in thickness, and are associated with mineralized alteration envelopes of up to several metres in thickness. Multiple veins occur sub-parallel to each other, as well as sub-parallel to the Piché lithologies and the LLCB. As mapped at the historic O'Brien mine, and now replicated in the modern drilling, individual veins have well-established lateral continuity, with steeply plunging grade shoots developed over significant lengths.

Since the end of 2024, Radisson has been pursuing a program of broad step-out drilling at O'Brien with the objective of determining the overall scope of mineralization at the Project to a depth of 2 kilometres (Figure 1). The priority is the quantity and distribution of mineral resources with step-outs rather than in-filling to upgrade the classification of the existing mineral resources.

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 program to 140,000 metres employing an eventual eight drill rigs (see Radisson news release dated October 16, 2025). An initial 35,000 metres of the program were completed in 2025, with 72,500 metres budgeted for 2026, and a further 32,500 metres scheduled for the first half of 2027.

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. Both Mr. Nieminen and Mr. Evans are 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, 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 29, 2025 for the year ended December 31, 2024, and the Company's Management's Discussion and Analysis dated November 26, 2025 for the three month period ended September 30, 2025, all of which are 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