Mr. Keith Bodnarchuk reports

COSA'S INITIAL DRILLING PROGRAM AT MURPHY LAKE NORTH URANIUM PROJECT IDENTIFIES TWO KILOMETRE STRIKE EXTENSION OF HURRICANE TREND

The inaugural drill program has confirmed that Cosa Resources Corp.'s 70-per-cent-owned Murphy Lake North uranium project contains up to two kilometres strike length of the extension of geology underpinning the Hurricane deposit. Murphy Lake North (MLN or the property) is a joint venture between Cosa and Denison Mines Corp., and is located in the eastern Athabasca basin, Saskatchewan. Cosa is the project operator and holds a 70-per-cent interest with Denison holding a 30-per-cent interest.

Highlights

• Located and defined the Hurricane trend extension within Murphy Lake North, the primary objective of the inaugural drilling campaign;
• Final drill hole intersected a significant zone of sandstone-hosted alteration and structure, overshooting optimal target by 25 metres; zone is open along strike in both directions and up to two kilometres of untested Hurricane trend strike length is interpreted within Murphy Lake North;
• Plans are in development for a fully financed summer drill program to follow up winter drilling results.

Keith Bodnarchuk, Cosa president and chief executive officer, commented: "The results of our inaugural drill program at the Murphy Lake North joint venture have exceeded our expectations and have confirmed our thesis that MLN hosts the same geology underpinning the Hurricane deposit only a few kilometres away. These initial results require immediate follow-up, leading to the decision to leave the drill and equipment on site to ensure a seamless summer start-up and significant cost savings. Having recently closed our $6-million oversubscribed private placement, we are fully funded for the foreseeable future and intend to meet with our joint venture partner and largest shareholder, Denison Mines, as soon as possible to develop plans for an exciting follow-up drill program."

Andy Carmichael, Cosa vice-president of exploration, commented: "The key objective of winter drilling at MLN was to locate and define the extension of Hurricane trend basement rocks and structures within the property. In addition to meeting that objective, the final hole of the winter program, MLN25-004, intersected a sandstone-hosted hydrothermal alteration zone cored by structure on the southern side of the trend and is interpreted to have overshot the optimal target by 25 metres. As only one drill hole at MLN has targeted this side of the trend, the alteration zone is wide open along strike to the east and west, indicating that MLN may host up to two kilometres of entirely untested Hurricane stratigraphy. We eagerly await analytical results which will be instrumental in prioritizing this zone for follow up among the abundant drill targets on this shallow, prospective project."

Murphy Lake North

Murphy Lake North covers a portion of the Larocque Lake trend and is located 2.7 kilometres east of the Hurricane deposit. Hurricane is the world's highest-grade indicated uranium resource and was discovered and delineated for IsoEnergy Ltd. by current members of Cosa's management, board of directors and advisers from 2018 through 2022. The Larocque Lake trend also hosts the Larocque Lake zone, Yelka prospect and Alligator Lake zone.

MLN also contains approximately six kilometres of conductive strike length oriented subparallel to conductive features associated with the Hurricane deposit. Limited historical drilling on MLN intersected weak uranium mineralization in the basement and zones of alteration and structure in the sandstone and basement. Historical drilling, completed before the discovery of Hurricane, focused on the western extremity of the property and left most of the conductive strike length untested. Abundant drill targets exist at MLN. The depth to the unconformity at MLN varies from approximately 170 to 250 metres.

Per the completed acquisition agreement between Cosa and Denison (see Cosa's news release dated Jan. 14, 2025), Cosa sole financed this initial MLN drill program as part of the company's obligation to financed 100 per cent of the first $1.5-million of exploration expenditures at the project by Dec. 31, 2027.

Winter drill program

A four-hole drill program totalling 1,739 metres was completed from mid-February through early March. The primary objectives of the program were to locate and define the interpreted strike extension of the Hurricane (CH1) trend and follow up historical intersections of weak uranium mineralization on the parallel Cyclone (CH2) trend to the south. Drill holes were collared at inclinations between negative 55 degrees and negative 67 degrees and true vertical depths are less than the down hole depths referred to herein.

Hurricane (CH1) trend

Three drill holes completed on the CH1 trend succeeded in locating graphitic basement rocks and structures interpreted as the extension of those underpinning the Hurricane deposit. Sandstones in all three drill holes were anomalous, with each hole containing widespread bleached zones. MLN25-004, the final hole of the winter program and the southernmost on the trend, intersected the strongest sandstone alteration on the project to date.

From 197 metres to the unconformity at 274 metres, MLN25-004 intersected a broad zone of moderate to strong hydrothermal alteration. The zone contained a broad interval of fracturing, faulting and desilicification from 223.5 to 260 metres where core loss averaged 20 per cent and hydrothermal hematite was locally present. Fracturing and associated desilicification decreased in the 14 metres immediately above the unconformity though the sandstone remained strongly bleached and contained patches of hydrothermal hematite. Basement rocks in MLN25-004 were strongly graphitic and pyritic from 390 metres to the end of hole and with a significant fault zone from 393.7 to 397.0 metres that includes cataclasite. Like at Hurricane, this prospective structure is located at the contact between graphitic and non-graphitic rocks.

MLN25-004 is interpreted to have overshot the optimal target by approximately 25 metres where basement faulting is inferred to root the altered structural zone in the sandstone. As MLN25-004 is the only drill hole on the project to target this portion of the Hurricane trend, the alteration zone is open along strike to the east and west.

MLN25-001 tested the up-dip projection of basement structures intersected by historical drill hole CRK-143. MLN25-001 intersected broad, weakly to moderately bleached zones through most of the sandstone and a strongly bleached, moderately desilicified zone in the basal three metres of sandstone. Strongly graphitic and pyritic basement rocks were intersected as well as a hematite-altered breccia 16 metres below the unconformity.

MLN25-003 targeted the hematitic structure 140 metres northeast of MLN25-001. Below broad, weakly to moderately bleached zones in the sandstone, MLN25-003 intersected primarily non-graphitic, non-pyritic basement rocks. MLN25-003 is interpreted to have been collared too far to the north to intersect Hurricane trend basement geology.

Additional work is warranted on the Hurricane (CH1) trend to:

1. Follow up the zone of alteration and structure intersected in the lower sandstone by MLN25-004;
2. Follow up the prospective cataclasite intersected in the basement by MLN25-004;
3. Continue testing the approximately two kilometres of Hurricane trend within MLN.

Cyclone (CH2) trend

Drill hole MLN25-002 was completed to follow up weak basement hosted mineralization intersected by historical drill hole CRK-144 on the CH2 trend, now referred to as the Cyclone trend by Cosa. MLN25-002 intersected broad, pervasively bleached zones and intervals of silicification throughout the sandstone as well as clay alteration in the lower sandstone, suggesting the presence of a significant hydrothermal alteration zone in the area. Graphitic rocks were not intersected in the basement, indicating the drill hole was not optimally targeted and the area remains prospective.

The widespread alteration in the sandstone of MLN25-002 and the historical intersections of weak uranium mineralization in the basement of CRK-144 emphasize the prospectivity of the CH2 trend. Drilling to date has targeted the western portion of MLN, leaving 90 per cent of this five-kilometre-long conductive trend undrilled.

Additional work is warranted along the CH2 trend to:

1. Follow up historical drilling results, including sandstone alteration and structure with anomalous lead (Pb) in historical hole CRK-145;
2. Drill test the 4.5 kilometres of untested conductive strike east of existing drilling.

Next steps

Planning is under way for a fully financed summer drill program. The focus of summer drilling is expected to be following up the MLN25-004 alteration zone along strike. Winter assay results are pending and will influence summer drilling, including whether to follow up MLN25-004 on section.

The drill rig and support equipment remain on site to minimize costs and increase efficiency for the planned summer drilling program.

About Cosa Resources Corp.

Cosa Resources is a Canadian uranium exploration company operating in Northern Saskatchewan. The portfolio comprises roughly 237,000 hectares across multiple 100-per-cent-owned and Cosa-operated joint venture projects in the Athabasca basin region, all of which are underexplored, and the majority reside within or adjacent to established uranium corridors.

In January of 2025, the company entered a transformative strategic collaboration with Denison Mines that has secured Cosa access into 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 long record of success in Saskatchewan. In 2022, members of the Cosa team were awarded the AME Colin Spence Award for their previous involvement in discovering IsoEnergy's Hurricane deposit. Prior to Hurricane, Cosa personnel led teams or had integral roles in the discovery of Denison's Gryphon deposit and 92 Energy's GMZ zone and held key roles in the founding of both NexGen and IsoEnergy.

The company's core focus throughout 2025 is drilling at the Murphy Lake North joint venture. Murphy Lake North is a 70/30 joint venture between Cosa and Denison, respectively, and is located at the northern end of the Larocque Lake trend. The project is within three kilometres of and on trend with the Hurricane deposit. Initial drilling completed by Cosa during winter 2025 intersected broad zones of hydrothermal alteration of the sandstone, associated with prospective basement structures interpreted as the strike extension of those controlling the Hurricane deposit. An expanded follow-up campaign is currently in planning for the summer season.

Technical disclosure

Historical drilling and geophysical results for Murphy Lake North and adjacent projects were sourced from the Saskatchewan Mineral Assessment Database (SMAD). SMAD sources for the Murphy Lake North project include file numbers 74I-0060, 74I09-0057, 74I09-0064, 74I09-0066, 74I09-0077, 74I09-0098 and MAW00510.

SMAD sources for drilling and geophysical results proximal to Murphy Lake North include 64L05-0161, 64L05-0180, 74I-0066, 74I-0067, 74I01-0114, 74I08-0056, 74I09-0053, 74I09-0061, 74I09-0064, 74I09-0071, 74I09-0079, 74I09-0087, 74I09-0088, 74I09-0090, 74I09-0091, 74I09-0092, MAW01939, MAW02327, MAW02599 and MAW02395.

Drill hole collar locations for Murphy Lake North and relevant along-strike drill holes were verified from air photos. The collar locations of Murphy Lake North drill holes CRK-144 and CRK-145 were verified on the ground using a handheld GPS and determined to be within 20 metres of the locations derived from air photos. Segments of drill core from CRK-143 and CRK-144 were reviewed in the field; further review was hampered by the deteriorated condition of core boxes.

Verification of historical geophysical results included confirming the locations of geophysical survey grids from air photos, compiling data from geophysical surveys completed post year 2000, engaging a consultant to reinterpret historical survey data and evaluating whether interpreted geophysical results could be reasonably explained by historical drilling results.

Qualified person

The company's disclosure of technical or scientific information in this press release has been reviewed and approved by Andy Carmichael, PGeo, 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.

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