RDS.V · 2026-09-21 12:00:00

Radisson Continues to Expand Scope of High- Grade Gold Mineralization Beneath the Former O'Brien Gold Mine with New Drill Results Including 68.24 g/t Gold over 6.2 Metres

Drill Results

Radisson Continues to Expand Scope of High-

Grade Gold Mineralization Beneath the Former

O'Brien Gold Mine with New Drill Results

Including 68.24 g/t Gold over 6.2 Metres

Rouyn-Noranda, Quebec--(Newsfile Corp. - September 21, 2026) -

Radisson Mining Resources Inc.

(TSXV: RDS) (OTCQX: RMRDF)

Radisson

" or the "

Company

") is pleased to announce the results

of eight new drill holes recently completed at its 100%-owned O'Brien Gold Project ("

O'Brien

" or the

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 ("g/t") gold ("Au") 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

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_f60ab4e7747e2ba4_001full.jpg

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. 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

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_radissonenfiguretwo.jpg

Table 1

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

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_radissontableone.jpg

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

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_radissonfigurethree.jpg

Figure 4:

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

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_f60ab4e7747e2ba4_008full.jpg

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 (%)

September 21, 2026

100%

September 2, 2026

100%

July 7, 2026

100%

June 22, 2026-O'Brien

100%

June 22, 2026-Thompson-Cadillac

50%

June 1, 2026

86%

April 30, 2026-O'Brien

100%

April 30, 2026-Thompson-Cadillac

22%

January 27, 2026

100%

January 6, 2026

83%

October 28, 2025

87%

September 8, 2025

87%

July 16, 2025

79%

April 2, 2025

100%

February 26, 2025

75%

December 16, 2024

100%

Total

128

106

83%

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")

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10977/315120_radissontablethree.jpg

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