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Cosa Announces Expansions to Orion Project and Joint Ventures with Denison Mines

Mergers & Acquisitions Partnerships & JV

Cosa Announces Expansions to Orion Project

and Joint Ventures with Denison Mines

Vancouver, British Columbia--(Newsfile Corp. - March 3, 2026) -

Cosa Resources Corp. (TSXV:

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

("

Cosa

" or the "

Company

") is pleased to announce

expansions to the Murphy Lake North ("

MLN

"), Darby ("

Darby

"), and Orion ("

Orion

") projects (Figure 1).

Darby and MLN are joint ventures (the "

Joint Venture

") between Cosa and Denison Mines Corp.

("

Denison

")

(TSX: DML) (NYSE American: DNN)

and are located 10 kilometres west of Cameco's

Cigar Lake Mine and three kilometres east of IsoEnergy's Hurricane Deposit, respectively. Cosa is the

operator of both and holds a 70% interest with Denison holding a 30% interest in each. Orion is 100%

owned by Cosa and is located 5 kilometres northwest of Darby.

Highlights

Six claims totalling 2,669 hectares added at Darby, MLN, and Orion to cover known conductive

features, inferred extensions, and areas proximal to favourable drilling results

All claims acquired for minimal cash consideration with no encumbrances

Justin Rodko P. Geo, Vice President of Corporate Development, commented: "

We are pleased to have

expanded the Darby and Murphy Lake North Joint Ventures as well as our underexplored and

prospective Orion project. All claims were acquired at low cost with no royalties and capture the

interpreted extensions of known conductive and/or mineralized trends and expand the projects

proximal to positive drilling results. We remain committed to advancing exploration and target

generation across our eastern Athabasca portfolio as the Company is actively drilling the Darby JV,

and winter drilling and ground-based resistivity surveying are planned to follow at MLN."

Darby

Two claims totalling 758 hectares were acquired and extend the northern border of Darby immediately

south of the Tucker Lake Uranium Zone (Figures 1 and 2). The expanded area covers the strike

extension of the Delta trend immediately northeast of the most recent electromagnetic (EM) survey

completed at Darby. The 2011 survey defined the northeast-trending Delta conductor, which has not

been drill tested and has been flagged by the JV for first pass drilling as early as H2-2026. Also in the

expanded area, ZTEM survey results suggest potential for an extension of the Echo trend. The Darby

claims were acquired from a third party for a cash payment with no encumbrances.

Murphy Lake North

Three claims totalling 345 hectares were acquired at Murphy Lake North to the south of the Cyclone

trend where Cosa's 2025 drilling intersected broad zones of sandstone alteration and structure above

graphitic basement rocks over a strike length of 2 kilometres (Figures 1 and 3). The claims were

acquired by low-cost staking.

Orion

One claim totalling 1,564 hectares was acquired at Orion. The claim extends Orion to the southeast and

covers a zone of enhanced basement-hosted conductivity near the edge of the conductivity model

generated from Z-Tipper Electromagnetic (ZTEM) surveying completed by Cosa in 2025. The zone of

basement conductivity coincides with an historical conductor in a digital compilation by the

Saskatchewan Government and is located within a magnetic high, suggesting a favourable structural

setting. The Orion claim was acquired from a third party for a cash payment with no encumbrances.

About Darby

Located 10 kilometres west of the Cigar Lake Mine, Darby contains multiple prospective conductive

trends and several historical intersections of weak uranium mineralization (Figures 1 and 2). Historical

drilling demonstrates that many of these trends are highly prospective for uranium deposits characteristic

of the eastern Athabasca Basin, yet most of the strike length has not been effectively evaluated. Work by

Cosa in 2025 prioritized these trends and identified several historical drill holes with results that suggest

proximity to uranium mineralization (See Cosa's news releases dated October 24, 2025 and January 20,

2026).

Cosa is currently undertaking the first diamond drilling program at Darby since 2009.

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 3). 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). Drilling by Cosa in 2025

intersected zones of sandstone alteration and structure associated with graphitic basement structures

along both trends. Following up these positive results is the primary 2026 objective at MLN.

Cosa intends to commence drilling at MLN in Q1 2026 which will be followed by project-wide DC-

Resistivity surveying ahead of an expanded summer drilling campaign.

About Orion

Orion is located 29 kilometres west of the Cigar Lake uranium mine and immediately east of Orano's

Parker Lake Project. Orion covers approximately 25 kilometres of strike length of the interpreted

extension of the Larocque Lake Trend and the interpreted intersection of the Larocque Lake and Cigar

Lake-Tucker Lake trends. The fertile Larocque Lake Trend hosts numerous occurrences of high-grade

mineralization to the northeast, including the Hurricane Deposit, while the portion covered by Orion is

highly underexplored and has been tested by only two drill holes.

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/9865/286087_bc8020ee5476b9d8_003full.jpg

Figure 2 - Darby Project Overview

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

https://images.newsfilecorp.com/files/9865/286087_bc8020ee5476b9d8_004full.jpg

Figure 3 - Murphy Lake North Project Overview

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

https://images.newsfilecorp.com/files/9865/286087_bc8020ee5476b9d8_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

1

, clay

alteration, and historical mineralization intersected nearby. Drilling at MLN will follow up 2025 drilling

which intersected broad zones of structurally controlled alteration over roughly 2 kilometres of strike

length.

1 - When analyzed using SRC's partial digestion and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method, Cosa considers uranium

concentrations in the Athabasca sandstone greater than 0.5 ppm to be elevated, greater than 1.0 ppm to be anomalous, and greater than 4 ppm to

be strongly anomalous.

Technical Disclosure

Historical drilling and geophysical results for Darby and MLN were sourced from the

Saskatchewan

Mineral Assessment Database

(SMAD). SMAD sources for Darby include file numbers 74H14-0021,

74H14-0023, 74H15-0041, 74H15-0053, 74H15-0055, 74H15-0056, 74H15-0066, 74H15-0067, 74I02-

0031, 74I02-0042, 74I02-0053, 74I02-0080, 74I02-0095, and MAW00516. Some confidential data and

reports not presently available via SMAD were supplied to Cosa by Denison. 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. Basement and lower sandstone

sections from most historical drill holes were relogged in 2024 and 2025 by Cosa. For Darby,

verification of geochemical results for drill holes completed between 2008 and 2010 was facilitated by

the reissuance of analytical certificates to Cosa by the Saskatchewan Research Council (SRC). Cosa

thanks the SRC for its valued assistance in increasing confidence in the historical dataset. Verification of

Orion drilling results includes relogging basement and lower sandstone from the two historical drill holes

completed on the Project.

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. For MLN,

Cosa engaged a consultant to re-interpret historical geophysical surveys to validate selected previous

interpretations.

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. 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/286087