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Cosa Reports 5.0 metres of Anomalous Radioactivity up to 13,900 CPS Intersected at Murphy Lake North Joint Venture with Denison Mines

Mergers & Acquisitions Exploration Programs Partnerships & JV

Cosa Reports 5.0 metres of Anomalous

Radioactivity up to 13,900 CPS Intersected at

Murphy Lake North Joint Venture with Denison

Mines

Vancouver, British Columbia--(Newsfile Corp. - March 24, 2026) -

Cosa Resources Corp. (TSXV:

COSA) (OTCQB: COSAF) (FSE: SSKU)

("

Cosa

" or the "

Company

") is pleased to report that the first

winter 2026 drill hole at the Company's Murphy Lake North Project ("

MLN

" or the "

Project

") has

intersected 5.0 metres of anomalous radioactivity. MLN is a joint venture (the "

Joint Venture

") between

Cosa and Denison Mines Corp.

(TSX: DML) (NYSE American: DNN)

("

Denison

") and is located 3

kilometres east of IsoEnergy's Hurricane Deposit in the eastern Athabasca Basin, Saskatchewan

(Figure 1). Cosa is the operator and holds a 70% interest with Denison holding a 30% interest.

Highlights

MLN26-013 intersected 5.0 metres of anomalous radioactivity up to 13,900 CPS

1

in the upper

basement approximately 260 metres vertically from surface

Strong, structurally controlled alteration in the sandstone and basement is open in all directions

MLN26-013 is the lone drill hole within a 1.2 kilometre section of the Cyclone trend

Drilling is ongoing and will test the immediate area around the radioactivity

Keith Bodnarchuk, President and CEO, commented: "

This intersection is an exceptional result. The

shallow depth, proximity to existing infrastructure, and our team's history with this area, elevates the

significance of this result. With a healthy treasury and strong support from our largest shareholder and

Joint Venture partner Denison Mines, we are well positioned to ambitiously drill test Murphy Lake

North for the remainder of 2026.

"

Andy Carmichael, Vice President of Exploration, commented:

"We are very encouraged that our first

drill hole of the winter program intersected a significant width of anomalous radioactivity while following

up the alteration identified in 2025. The mineralization, structure, and alteration intersected by

MLN26-013 are open in all directions and the nearest drilling is 600 metres away along strike to the

east and west. We'd like to recognize the instrumental roles our technical team of Keane Baseden

(Senior Geologist), Haley Kitt and Kelly Stasiuk (Exploration Geologists) played in achieving this

excellent result. We plan to use the remainder of our winter program to follow up the results of MLN26-

013."

MLN Winter Drilling

Winter drilling at MLN was planned to follow up summer 2025 results at the Cyclone trend where broad

zones of structure and alteration were intersected over a 2 kilometre strike length (Figure 2). The

program's objectives were to target a gap in drilling at Cyclone and evaluate a potential untested trend

approximately 100 metres south of Cyclone. Both planned target areas are best accessed in winter due

to the presence of lakes. MLN26-013 was the first drill hole of the program and targeted the main

Cyclone trend within a 1,200-metre gap between existing drill fences.

MLN26-013

MLN26-013 intersected broad zones of moderately to strongly altered sandstone from 200 metres to the

unconformity at 299.4 metres. The strongest structure was intersected from 221 to 242 metres and is

pervasively bleached and desilicified. The basal 9 metres of sandstone contains metre-scale zones of

moderate to strong argillization within broader pervasively bleached sections and hosts hydrothermal

hematite in the basal 1 metre.

The unconformity was intersected approximately 250 metres vertically from surface. The upper

basement is strongly and pervasively argillized and variably limonitized, hematitized, and chloritized to

306 metres (Figure 3). Graphitic and sulphidic pelitic gneiss immediately below the strongly altered zone

hosts several intervals of anomalous radioactivity

1

between 306.5 and 313.5 metres ranging from 400 to

13,900 cps (Table 1). This broader zone includes a 5.0 metre interval of continuously anomalous

radioactivity from 308.5 to 313.5 metres. Core recovery through the mineralized zone was 100%.

Basement below the radioactive zone is a sequence of dominantly non-graphitic metasediments hosting

graphitic faulting. The drill hole was terminated at 425 metres.

Table 1 - Winter 2026 MLN Drilling Program Results

Hole

ID

From

(m)

To

(m)

Length

(m)

Radioactivity

1, 2

(CPS)

Orientation

(Azi./Dip)

Location

MLN26-013

306.5

307.0

0.5

>350

166 / -60

Section 3200E

307.5

308.0

0.5

>1,000

and

308.5

313.5

5.0

>1,000

including

310.5

313.0

2.5

>5,000

including

310.5

311.0

0.5

>13,000

1

.

Radioactivity is total gamma from drill core measured with an RS-125 hand-held spectrometer

2

.

Measurements of total gamma on drill core are an indication of uranium content, but may not correlate with chemical assays

Next Steps

The remaining two targets planned for the program have been deferred in favour of immediate follow up

of MLN26-013 which is ongoing. Chemical assays from MLN26-013 are pending.

About Murphy Lake North

MLN covers a portion of the Larocque Lake trend and is located 2.7 kilometres east of the Hurricane

deposit (Figures 1 and 2). Hurricane is the world's highest-grade indicated uranium resource and was

discovered and delineated for IsoEnergy Ltd. by current members of Cosa's team. The Larocque Lake

trend also hosts the high-grade Larocque Lake Zone, Yelka Prospect, and Alligator Lake Zone. MLN

contains the along-strike extension of basement geology underlying the Hurricane deposit (the Hurricane

trend), as well as a parallel conductive trend to the south (the Cyclone trend). Cosa's winter 2026 drill

program intersected several meters of basement hosted radioactivity within a broader zone of strong

structure and alteration at the Cyclone trend.

Following up these results is the primary objective for the

remainder of 2026 at MLN.

1 - Cosa considers radioactivity anomalous when it (i) exceeds 350 cps measured with a Radiation Solutions RS-125 hand held spectrometer, (ii) is

accompanied by structure and/or hydrothermal alteration consistent with Athabasca unconformity related uranium deposits, and (iii) spectrometric

assay by RS-125 indicates a uranium to be the dominant source.

Figure 1 - Cosa's Eastern Athabasca Uranium Projects with Joint Venture Projects

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

https://images.newsfilecorp.com/files/9865/289682_a604561404c0fb07_003full.jpg

Figure 2 - MLN Project Overview

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

https://images.newsfilecorp.com/files/9865/289682_a604561404c0fb07_004full.jpg

Figure 3 - MLN26-013 Mineralized Zone

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

https://images.newsfilecorp.com/files/9865/289682_a604561404c0fb07_005full.jpg

About Cosa Resources Corp.

Cosa Resources is a Canadian uranium exploration company operating in northern Saskatchewan. The

portfolio comprises roughly 237,000 ha across multiple underexplored 100% owned and Cosa-operated

joint venture projects in the Athabasca Basin region, the majority of which reside within or adjacent to

established uranium corridors.

In January of 2025, the Company entered a transformative strategic collaboration with Denison Mines

(TSX: DML) (NYSE American: DNN) that has secured access to several additional highly prospective

eastern Athabasca uranium exploration projects. As Cosa's largest shareholder, Denison gains

exposure to Cosa's potential for exploration success and its pipeline of uranium projects.

Cosa's award-winning management team has a track record of success in Saskatchewan. In 2022,

members of the Cosa team were awarded the AME Colin Spence Award for the discovery of the

Hurricane uranium deposit. Cosa personnel led teams or had integral roles in the discovery of Denison's

Gryphon deposit and held key roles in the founding of both NexGen and IsoEnergy.

The Company's focus throughout 2026 is drilling at the Darby and MLN projects in the eastern

Athabasca Basin. Both projects are operated by Cosa and are 70/30 joint ventures between Cosa and

Denison respectively. Drilling at Darby will evaluate target areas with anomalous uranium, clay alteration,

and historical mineralization intersected nearby. Drilling at MLN will follow up a zone of newly identified

anomalous radioactivity intersected by winter 2026 drill hole MLN26-013.

Technical Disclosure

Historical drilling and geophysical results for MLN were sourced from the

Saskatchewan Mineral

Assessment Database

(SMAD). SMAD sources for MLN and adjacent projects include file numbers

64L05-0161, 64L05-0180, 74I-0060, 74I-0066, 74I-0067, 74I01-0114, 74I08-0056, 74I09-0053, 74I09-

0057, 74I09-0061, 74I09-0064, 74I09-0066, 74I09-0071, 74I09-0077, 74I09-0079, 74I09-0087, 74I09-

0088, 74I09-0090, 74I09-0091, 74I09-0092, 74I09-0098, MAW00510, MAW01939, MAW02327,

MAW02599, and MAW02395. Data and reports related to the 2020 ground EM survey completed by

Denison are not presently available via SMAD and were supplied to Cosa by Denison.

Verification of historical drilling results included confirming historical drill hole collar locations from air

photos and ground checking selected collars with a handheld GPS unit. Verification of historical

geophysical results included confirming the locations of geophysical survey grids from air photos,

compiling survey data and interpretations, and evaluating whether interpreted geophysical results could

be reasonably explained by historical and current drilling results. Additionally, Cosa engaged a

consultant to re-interpret historical geophysical surveys to validate selected previous interpretations.

All drill core is scanned with an RS-125 hand held spectrometer to check for radioactivity. Intervals of

anomalous radioactivity are removed in 0.5 metre core lengths to an area of background radioactivity

and average radioactivity for the 0.5 m interval is measured. Cosa drill holes are also surveyed using an

Imdex EZ Gamma (NOVAx) down hole probe to provide a continuous log of radioactivity at 0.1 metre

intervals. Down hole probe results are compared to RS-125 results to verify the depth and strength of

radioactive intervals and to assess for radioactivity though sections of lost core.

Qualified Person

The Company's disclosure of technical or scientific information in this press release has been reviewed

and approved by Andy Carmichael, P.Geo., Vice President, Exploration for Cosa. Mr. Carmichael is a

Qualified Person as defined under the terms of National Instrument 43-101. All radioactivity

measurements reported herein are total gamma from an RS-125 hand-held spectrometer. Chemical

assays are pending. As the orientation of mineralization is unknown, true widths are unknown and

reported mineralized intervals represent core lengths. This news release refers to neighbouring

properties in which the Company has no interest. Mineralization on those neighbouring properties does

not necessarily indicate mineralization on the Company's properties.

Contact

Keith Bodnarchuk, President and CEO

[email protected]

+1 888-899-2672 (COSA)

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in policies

of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Cautionary Statements

This press release contains forward-looking information within the meaning of Canadian securities laws

(collectively "forward-looking statements"). Forward-looking statements are typically identified by words

such as: believe, expect, anticipate, intend, estimate, plans, postulate and similar expressions, or are

those, which, by their nature, refer to future events. All statements that are not statements of historical fact

are forward-looking statements. These forward-looking statements or information may relate to

anticipated exploration, development and/or expansion activities, including exploration of the Company's

current Projects; the collaboration with Denison, including the Joint Venture, and the anticipated benefits

thereof; and the outlook regarding Cosa's business plans and objectives.

Such forward-looking information and statements are based on numerous assumptions, including

among others, that the results of planned exploration activities are as anticipated, the cost of planned

exploration activities are as anticipated, that general business and economic conditions will not change

in a material adverse manner, that financing will be available if and when needed and on reasonable

terms, that third party contractors, equipment and supplies and governmental and other approvals

required to conduct Cosa's planned exploration activities will be available on reasonable terms and in a

timely manner. Although the assumptions made by Cosa in providing forward-looking information or

making forward-looking statements are considered reasonable by management at the time, there can

be no assurance that such assumptions will prove to be accurate.

By their nature, forward-looking statements involve known and unknown risks, uncertainties and other

factors which may cause our actual results, performance or achievements, or other future events, to be

materially different from any future results, performance or achievements expressed or implied by such

forward-looking statements. Such factors and risks include, among others: Cosa may require additional

financing from time to time in order to continue its operations which may not be available when needed

or on acceptable terms and conditions acceptable; Cosa may not be able to maintain compliance with

its contractual obligations with third parties; Cosa may not be able to maintain compliance with extensive

government regulation applicable to its operations; domestic and foreign laws and regulations could

adversely affect Cosa's business and results of operations; the stock markets have experienced volatility

that often has been unrelated to the performance of companies and these fluctuations may adversely

affect the price of Cosa's securities, regardless of its operating performance; the ongoing military

conflict in Ukraine, and other risk factors set out in Cosa's public disclosure documents.

The forward-looking information contained in this news release represents the expectations of Cosa as

of the date of this news release and, accordingly, is subject to change after such date. Readers should

not place undue importance on forward-looking information and should not rely upon this information as

of any other date. Cosa does not undertake any obligation to update these forward-looking statements in

the event that management's beliefs, estimates or opinions, or other factors, should change.

To view the source version of this press release, please visit

https://www.newsfilecorp.com/release/289682