Cosa Announces Winter 2026 Drilling Plans for Joint Ventures with Denison Mines

Rhea-AI Summary

Cosa (TSX-V: COSA / OTCQB: COSAF) and Denison (TSX: DML / NYSE: DNN) announced winter 2026 drill programs at the Darby and Murphy Lake North (MLN) joint-venture projects in the eastern Athabasca Basin, near Cigar Lake and Hurricane. Cosa (operator, 70%) and Denison (30%) plan ~2,500 metres at Darby and ~1,200 metres at MLN to test historical anomalous uranium in lower sandstone and graphitic basement faults. Denison will participate in funding 2026 MLN exploration to maintain its 30% interest. Camp construction is underway with Darby drilling expected to start before end of January and MLN in March.

Positive

• Darby drill program planned for 2,500 metres winter 2026
• MLN drill program planned for 1,200 metres targeting a 1,200m gap
• Denison commitment to participate in 2026 MLN funding to maintain 30% interest
• Proximity to Cigar Lake and Hurricane deposits enhances prospectivity
• Operator status — Cosa holds 70% and will run programs

Negative

• None.

Key Figures

Darby winter drilling: Approximately 2,500 metres MLN winter drilling: Approximately 1,200 metres Cosa JV interest: 70% +5 more

8 metrics

Darby winter drilling Approximately 2,500 metres Planned drilling at Darby in winter 2026

MLN winter drilling Approximately 1,200 metres Planned drilling at Murphy Lake North in winter 2026

Cosa JV interest 70% Cosa interest in Darby and MLN joint ventures

Denison JV interest 30% Denison interest in Darby and MLN joint ventures

Gamma conductive strike Over 4 kilometres Conductive strike length at Gamma trend

Basement mineralization 0.13% U3O8 over 0.3 metres Intersection in DB-27 at Delta trend

Basal sandstone interval 108 metres Basal sandstone interval with anomalous uranium in DB-17

Anomalous interval 48 metres Continuously anomalous uranium content in DB-27 basal sandstone

Market Reality Check

Price: $3.75 Vol: Pre-news volume at 67,560...

normal vol

$3.75 Last Close

Volume Pre-news volume at 67,560,834 vs 20-day average 45,591,917 (relative volume 1.48). normal

Technical Price 3.69 trades above 200-day MA at 2.24 and sits 2.89% below 52-week high 3.8.

Peers on Argus

Before this JV drilling update, DNN was flat (0%) while several uranium peers mo...

1 Up

Before this JV drilling update, DNN was flat (0%) while several uranium peers moved: UUUU +9.75%, UEC +2.67%, URG +5.49%, NXE +1.27%, and LEU -2.19%. Momentum scanner flagged UROY up 4.45% with no news. DNN’s flat trade suggests this article added company-specific context rather than driving a sector-wide move.

Historical Context

5 past events · Latest: Jan 08 (Positive)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Jan 08	Power line update	Positive	+0.0%	New 138kV SaskPower line providing up to 8.8 MW to Phoenix site.
Jan 02	Phoenix capex update	Positive	+13.9%	Readiness to commence Phoenix ISR construction with $600M capex and funding.
Dec 17	New exploration JVs	Positive	-4.6%	Closing Skyharbour deal and forming four JVs adjacent to Wheeler River.
Dec 04	Impact benefit deal	Positive	+5.2%	IBA and exploration agreement with Métis Nation–Saskatchewan supporting Wheeler River.
Dec 01	Community agreement	Positive	-1.6%	Nuhenéné Benefit Agreement covering multiple northern Saskatchewan uranium projects.

Pattern Detected

Recent positive project and partnership news has produced mixed reactions, with both strong gains and selloffs, and several divergences where constructive updates saw little or negative price response.

Recent Company History

Over the last two months, Denison reported multiple Wheeler River milestones and community agreements. On Dec 1, 2025 and Dec 4, 2025, benefit and impact agreements formalized local consent. On Dec 17, 2025, Denison formed four exploration JVs adjacent to Wheeler River. Early January 2026 updates highlighted Phoenix ISR construction readiness with $600 million capex and grid power availability via a new 138kV transmission line. Today’s JV drilling plans add to this exploration and development pipeline rather than altering capital or permitting timelines.

Market Pulse Summary

This announcement outlines detailed winter 2026 drilling programs at the Darby and Murphy Lake North...

Analysis

This announcement outlines detailed winter 2026 drilling programs at the Darby and Murphy Lake North joint ventures, where Cosa holds 70% and Denison 30%. Targets focus on structures with anomalous uranium, including a 0.13% U3O8 over 0.3 metres interval at Delta and multi‑kilometre conductive trends. In the broader context of Denison’s recent Phoenix ISR construction readiness and community agreements, this update adds exploration depth rather than changing capital or permitting timelines. Investors may track future drill results and follow-up campaigns across the Gamma, Charlie, and Cyclone trends.

Key Terms

u3o8, graphitic faults, unconformity, dc-resistivity, +4 more

8 terms

u3o8 technical

"DB-27 intersected 0.13% U3O8 over 0.3 metres 16 metres below the unconformity"

U3O8 is the chemical name for a stable form of uranium oxide commonly called “yellowcake,” the concentrated powder produced after uranium ore is processed. Investors track U3O8 because it represents the raw material that is turned into nuclear fuel; its supply, demand and price act like a commodity indicator that can move the value of mining companies, utilities and firms tied to the nuclear fuel chain. Think of it as the crude oil equivalent for nuclear power — a basic feedstock whose availability and cost affect an entire industry.

graphitic faults technical

"Graphitic faults were intersected 45 and 55 metres below the unconformity"

Graphitic faults are imperfections in the layered structure of graphite or graphene where sheets are misaligned, missing atoms, or otherwise disrupted—think of a deck of cards with bent or swapped cards that prevent the stack from sitting flush. For investors, these faults matter because they degrade electrical and thermal performance, reduce battery life or material strength, and raise manufacturing defects and costs, all of which can affect product quality, production yields and profitability.

unconformity technical

"The intersection of these graphitic faults with the unconformity, proximal to highly anomalous uranium"

An unconformity is a break or gap in the sequence of rock layers where older rocks sit directly against much younger rocks because time was lost to erosion or non-deposition — like finding two pages of a book glued together while several chapters are missing. For investors in mining and exploration, unconformities matter because they can concentrate minerals or change where valuable deposits are found, so recognizing them helps guide drilling, shape resource estimates and influence project value and risk.

dc-resistivity technical

"a property-wide DC-Resistivity survey planned for the spring"

DC-resistivity is a geophysical survey technique that maps how easily the ground conducts electricity by sending a steady electrical current into the earth and measuring voltage differences at the surface. Like probing with a battery and voltmeter, it reveals buried features such as mineral deposits, groundwater, contamination or voids, helping investors assess the size, quality and cost risk of exploration, environmental cleanup or construction projects.

illite technical

"include continuously anomalous uranium ... illite and chlorite enrichment, bleached zones"

Illite is a common fine-grained clay mineral with flaky, sheet-like crystals that often forms in soils and sedimentary rocks. For investors, it matters because the amount and behavior of illite can affect how easily minerals or hydrocarbons are extracted, the stability of mine walls and tailings, and the efficiency of processing methods—think of it as a powdery ingredient that can change how well a recipe comes together in mining and drilling operations.

chlorite technical

"include continuously anomalous uranium ... illite and chlorite enrichment, bleached zones"

Chlorite is a chemical compound often encountered as the chlorite ion or its salts (for example, sodium chlorite) and as a disinfectant and bleaching agent used in water treatment, sanitation, and some industrial processes. Investors care because its production, sale, or regulatory restrictions can affect manufacturers and users — like a utility shutting down a pump because of water rules — creating costs, supply changes, or liability risks that influence company profits and stock values.

hydrothermal hematite technical

"bleached zones, and hydrothermal hematite. DB-09 intersected graphitic faults"

Hydrothermal hematite is a dense, iron-rich mineral that forms when hot, mineral-laden fluids move through rock and leave behind iron oxide as they cool, often creating concentrated bands or zones. For investors, its presence can point to a commercially viable iron ore deposit and sometimes accompanies other valuable metals like gold, so discovering hydrothermal hematite can raise a project's resource grade and improve the economics of mining—like finding a concentrated pocket of metal that makes extraction more rewarding.

basement metasediments technical

"sandstone uranium content above basement metasediments that were altered near the end"

Basement metasediments are ancient sedimentary rocks that have been changed by heat and pressure deep in the Earth, turning originally soft layers into harder, more compact rock—think of wet clay that has been baked into pottery. For investors in mining or exploration, they matter because these rocks can host or hide valuable mineral deposits and they influence how easy or costly it will be to drill, extract resources, and build infrastructure.

AI-generated analysis. Not financial advice.

Vancouver, British Columbia--(Newsfile Corp. - January 21, 2026) - Cosa Resources Corp. (TSXV: COSA) (OTCQB: COSAF) (FSE: SSKU) ("Cosa" or the "Company") is pleased to announce drilling plans for the Company's Darby and Murphy Lake North ("MLN") projects (Figure 1). Darby and MLN are joint ventures (the "Joint Venture") between Cosa and Denison Mines Corp. (TSX: DML) (NYSE American: DNN) ("Denison") and are located 10 kilometres west of Cameco's Cigar Lake Mine and three kilometres east of IsoEnergy's Hurricane Deposit, respectively, in the eastern Athabasca Basin, Saskatchewan. Cosa is the operator of both projects and holds a 70% interest with Denison holding a 30% interest in each.

Highlights

• Drilling at Darby will directly follow up compelling historical results including anomalous uranium content in the sandstone and weak uranium mineralization in the basement

• Drilling at MLN will further evaluate the kilometre-scale structure and alteration zone at the Cyclone trend and an additional parallel trend to the south

• Denison participating in funding 2026 exploration at MLN to maintain its 30% interest

Keith Bodnarchuk, President and CEO, commented: "Identification of additional drill ready targets proximal to historical intersections of uranium mineralization and under modest sandstone cover has added to our excitement to commence drilling at Darby. With support and participation from Denison, our Joint Venture partner and largest shareholder, we are fully funded and prepared for an exciting year of exploration at both Darby and Murphy Lake North. We thank Denison for their continued guidance and commitment to working towards exploration success at these projects. Camp construction is well underway, and we expect drilling to commence at Darby next week."

Andy Carmichael, Vice President of Exploration, commented: "Retention of high-quality data by Denison combined with the experience gained over the last 15 years has allowed us to identify what may be some of the last remaining high-caliber untested target areas near Cigar Lake. Darby hosts five historical intersections of mineralization proximal to untested structures across multiple trends. Our initial target areas have coincident untested structures, alteration, and anomalous uranium content in the lower sandstone. At MLN, we are eager to continue testing large gaps in strike where compelling structure and alteration have been intersected by widely spaced drilling on the Cyclone trend. Evaluation of an additional trend south of Cyclone is also a priority objective for this winter. Our decision to prioritize targets under frozen lakes, combined with a property-wide DC-Resistivity survey planned for the spring, is aimed at identifying the most prospective targets for an expanded follow up campaign in the summer."

Darby Winter Drilling

Approximately 2,500 metres are planned at Darby in winter 2026 to begin testing the high priority targets identified by Cosa's 2025 core relogging and reinterpretation program. High priority targets are the immediate vicinities of drill holes which intersected zones of coincident sandstone alteration and anomalous¹ uranium content proximal to significant graphitic basement faults. Up to four initial target areas will be evaluated during winter 2026 (Figures 2 and 3).

• Gamma Trend

The Gamma trend contains over 4 kilometres of conductive strike length (Figure 2). Only two of four historical drill holes at Gamma intersected conductive basement rocks and none intersected the optimal target. The trend is considered highly prospective based on the presence of anomalous sandstone uranium content proximal to graphitic basement faults (Figure 3) and numerous intersections of uranium mineralization along trend immediately north of Darby.

Historical hole DB-17 intersected continuously elevated to anomalous uranium content in the basal 108 metres of sandstone with coincident clay alteration and bleached zones (Figure 3). Graphitic faults were intersected 45 and 55 metres below the unconformity. The intersection of these graphitic faults with the unconformity, proximal to highly anomalous uranium in the lower sandstone, is the initial follow up target at Gamma in winter 2026. Over 2.5 kilometres to the south, drill hole DB-22 intersected several intervals of elevated to anomalous sandstone uranium content above basement metasediments that were altered near the end of the drill hole. Follow up of DB-22 is a priority target.

• Charlie Trend

DB-09, the westernmost drill hole at Charlie, intersected multiple zones of elevated to strongly anomalous uranium content in the lower 115 metres of sandstone (Figures 2 and 3). These intervals include continuously anomalous uranium over the basal 42 metres, illite and chlorite enrichment, bleached zones, and hydrothermal hematite. DB-09 intersected graphitic faults in the basement 30 to 60 metres below the unconformity. The intersection of these graphitic faults with the unconformity, proximal to strongly anomalous uranium in the lower sandstone, is a priority follow up target.

• Delta Trend

At Delta, the basal sandstone in DB-27 is pervasively bleached with illite and chlorite enrichment and includes a 48-metre interval of continuously anomalous uranium content (Figures 2 and 3). In the basement, DB-27 intersected 0.13% U₃O₈ over 0.3 metres 16 metres below the unconformity and graphitic faults 80 metres below the unconformity. The intersection of basement faulting with the unconformity is the initial target at the Delta trend.

For further details on the Charlie and Delta trends and targets, refer to Cosa's news release dated October 14, 2025.

MLN Winter Drilling

Drilling plans at MLN comprise approximately 1,200 metres and will follow up summer 2025 results at the Cyclone trend where broad zones of structure and alteration were intersected over a two-kilometre strike length (Figure 4). Winter drilling will target a 1,200-metre gap in drilling where a lake prevents summer access. Drilling will also follow up intensely graphitic rocks and faulting intersected deep in the basement of MLN25-007, where the primary target is the up-dip projection of this horizon to the unconformity. The target is interpreted to lie approximately 100 metres south of MLN25-007 and potentially represents an untested trend parallel to Cyclone.

Next Steps

At Darby, camp construction is nearing completion and will be followed by mobilization of drilling equipment and personnel, with drilling expected to begin before the end of January. Cosa intends to use the winter access trail to mobilize supplies and equipment required for continued testing of high priority targets planned for summer 2026.

At MLN, establishment of winter trails is ongoing in advance of drilling planned to begin in March. During the program, Cosa plans to mobilize supplies and equipment to support property-wide DC-resistivity surveying and a larger summer drilling program.

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 release dated October 24, 2025).

Darby was last drilled in 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.

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.

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/9865/281057_fc770e53f40208fb_003full.jpg

Figure 2 – Darby Project Overview

To view an enhanced version of this graphic, please visit:
https://images.newsfilecorp.com/files/9865/281057_fc770e53f40208fb_004full.jpg

Figure 3 – Cross Sections of Anomalous Historical Drill Results from Darby High Priority Target Areas

To view an enhanced version of this graphic, please visit:
https://images.newsfilecorp.com/files/9865/281057_fc770e53f40208fb_005full.jpg

Figure 4 – Murphy Lake North Project Overview

To view an enhanced version of this graphic, please visit:
https://images.newsfilecorp.com/files/9865/281057_fc770e53f40208fb_006full.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 2025 drilling which intersected broad zones of structurally controlled alteration over roughly 2 kilometres of strike length.

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 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
info@cosaresources.ca
+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/281057

FAQ

When will Cosa and Denison begin drilling at Darby and MLN in 2026 (DNN)?

Drilling at Darby is expected to begin before the end of January 2026 and MLN drilling is planned to start in March 2026.

How many metres of drilling are planned at Darby and Murphy Lake North (DNN) for winter 2026?

Cosa plans approximately 2,500 metres at Darby and 1,200 metres at Murphy Lake North during winter 2026.

What is Denison's equity position and funding role in the Darby and MLN joint ventures (DNN)?

Denison holds a 30% interest in each JV and will participate in funding 2026 MLN exploration to maintain its 30% stake.

What are the main geological targets for Cosa's 2026 drills near Cigar Lake (DNN)?

Programs target anomalous uranium in the lower sandstone and intersections of graphitic basement faults at the unconformity across Gamma, Charlie, Delta and Cyclone trends.

Will Cosa use geophysics as part of the 2026 exploration program (DNN)?

Yes; a property-wide DC-resistivity survey is planned for spring 2026 to refine targets for a larger summer campaign.