Welcome to Nuclear Update.

There's a version of uranium exploration that gets covered in the press.

It's the one with the headline.

The drill result with the spectacular grade. The discovery announcement. The stock that moves 40% in a day.

That version is real, and it happens, but it is the end of a much longer story.

The part that doesn't make headlines is what geologists actually spend most of their time doing. Learning to read a system before it decides to show itself.

That skill, pattern recognition built through years of drilling the same basin, reading the same rock types, recognizing the same signals before they become discoveries, is worth more than most investors realize.

Today we're going to talk about what those patterns look like, and why the signals coming out of one specific trend in the Athabasca deserve attention right now.

This is a sponsored feature in collaboration with Cosa Resources (TSX.V: COSA, OTCQB: COSA, FSE: SSKU). This is the second post in the Cosa series. If you missed the first part, read it here.

🗺️ Why the Athabasca Basin Is Different

The Athabasca Basin in northern Saskatchewan is not your average uranium district.

Grades here are not measured in tenths of a percent.

The Hurricane deposit, discovered in 2018, came in at over 34% U₃O₈ average grade in indicated resources. The world's highest-grade indicated uranium resource!

Cigar Lake, the operating mine that supplies roughly 15% of the world's uranium, peaks at grades that dwarf nearly anything found anywhere else on earth.

The deposits here are called unconformity-related uranium deposits. They form at the geological boundary between the ancient basement rock below and the younger Athabasca sandstone above.

Uranium-bearing fluids migrate through faults and fractures, get trapped at that boundary, and precipitate as high-grade ore.

There is a specific recipe.

You need graphitic basement units, which focus fluid flow.

You need faulting along those units to provide the pathways.

You need hydrothermal alteration in both the sandstone above and the basement below, a sign that fluids have moved through.

And you need those features to converge near the unconformity.

When all of that shows up together, you pay attention.

The Athabasca Basin has produced enough discoveries that the geological signature is now well understood. Teams that have already found deposits here know exactly what they are looking for, and they know it when they see it again.

🔬 What Alteration Is Actually Telling You

One of the most common phrases in Athabasca drilling reports is "alteration," and it tends to get treated like background noise.

It is not background noise.

Hydrothermal alteration is the chemical fingerprint left behind when hot, reactive fluids have moved through rock. In the Athabasca, those fluids are the same ones that carry uranium.

The alteration patterns they leave, bleached sandstone, clay zones, degraded graphitic basement are the most reliable indicators that you're in the right neighborhood.

Think of it like reading smoke. The fire has come through. The question is how recently, and whether it came back.

At Hurricane, the alteration signature is now well documented: bleached and silicified zones in the sandstone, enveloping a clay-cored interval, with graphitic fault zones in the basement below and radioactivity concentrated at the unconformity.

That model didn't arrive fully formed. It was built hole by hole, by a team learning the system from the inside out.

That same template is now being applied three kilometers away, on a parallel trend at Murphy Lake North (MLN). And that is where Cosa Resources comes in.

⚛️ Cosa Resources

Cosa Resources (TSX.V: COSA, OTCQB: COSAF, FSE: SSKU) is a Canadian uranium exploration company operating in the eastern Athabasca Basin, with roughly 237,000 hectares across multiple projects in one of the world's most productive uranium jurisdictions.

Cosa's leadership isn't learning the Athabasca Basin. They built their careers finding uranium in it.

Chairman Steve Blower was part of the Hurricane discovery team and worked on Denison's Phoenix and Gryphon deposits.

VP of Exploration Andy Carmichael was a core member of that same Hurricane team. Strategic advisor Craig Parry co-founded NexGen and IsoEnergy.

This is very specific pattern recognition applied to very specific ground, in a basin where reading the geology correctly is the whole game.

The strategic collaboration with Denison Mines adds another layer. Denison is Cosa's largest shareholder and joint venture partner on multiple projects, with board representation, technical involvement, and active financial participation in drilling programs.

For a junior explorer, that alignment with one of the Athabasca's most established developers is not a small thing.

⚡ What the Winter Drilling Program Just Showed

A single drill hole intersection is a data point. Multiple holes confirming the same features along strike is a pattern.

Cosa just published the full results from its winter 2026 drilling program at Murphy Lake North (MLN), and the pattern is developing in a way that warrants careful attention.

Five drill holes were completed on the Cyclone trend, totaling 2,015 metres. Three of those five intersected anomalous radioactivity, in two discrete zones, with open strike length of at least 600 metres in both directions.

Three out of five holes hitting radioactivity along a single trend means the system is not a point source. It has lateral extent. It has room to grow.

Cosa's CEO Keith Bodnarchuk, and VP of Exploration Andy Carmichael break down this anomalous radioactivity they detected in this video from The KE Report.

The first hole, MLN26-013, had already been reported: 5.0 metres of continuously anomalous radioactivity in the upper basement, with readings up to 13,900 counts per second, within faulted graphitic gneiss and strong hydrothermal alteration.

Follow up hole MLN26-014 confirmed anomalous radioactivity to the north. MLN26-016, drilled 50 metres north on the same section, intersected a 1.0 metre interval of anomalous radioactivity immediately below the unconformity.

That is exactly where uranium deposits in this basin concentrate.

And at just 260 metres vertically from surface, it is relatively shallow, which matters when you start thinking about what future drilling campaigns cost to run.

The Cyclone trend structural corridor is over 100 metres wide, hosting significant alteration consistent with the major uranium deposits of the eastern Athabasca Basin. The full width remains unknown, which means there is still ground to test.

Cosa's VP of Exploration describes the Cyclone trend geology as having similarities to the Hurricane deposit, bleached sandstone, clay-cored alteration zones, graphitic fault zones in the basement below.

These are not people reaching for a comparison for marketing purposes. They are geologists who built the Hurricane model from scratch and are now looking at a different trend through the same interpretive lens.

Assays for all winter holes are still pending. The chemical confirmation of what the radioactivity meters have already been reading is still ahead.

The balance sheet is funded. The drill is already on site for a rapid summer restart. And 600 metres of open strike in both directions means the next round of drilling has no shortage of targets.

That is not the discovery announcement. But it is what the geology looks like before one.

⚛️ Wrapping Up

Uranium deposits don't announce themselves. They leave clues: in the alteration, in the structure, in the way radioactivity keeps showing up in the same corridor across multiple holes even before the system has fully revealed itself.

The Athabasca rewards teams who can read those clues and keep drilling when the pattern is building but the headline hasn't arrived.

At Murphy Lake North, the pattern is building.

Summer 2026 will tell us more.

– Fredrik

For more information on Cosa Resources and its Athabasca Basin exploration programs, visit their website https://cosaresources.ca/ or email the company at [email protected].

Disclosure: Nuclear Update (“NU”) is an independent publication focused on uranium, energy, and related markets. Data and information in this article are provided from third-party sources, and NU is not responsible for their accuracy or completeness. Readers should always perform their own research and due diligence on any company or investment discussed. NU does not provide personalized investment advice and is not an investment advisor; any companies or profiles mentioned may not be suitable for all investors. NU received compensation from Cosa Resources Corp for the preparation and dissemination of this sponsored edition.

DISCLAIMER: The content in this article is for informational and educational purposes only and is not financial advice. It should not be interpreted as a recommendation or solicitation to buy or sell any securities. Markets move quickly, opinions can change, and outcomes are uncertain. Always consult a licensed professional before making any investment decisions. NU and its authors are not responsible for any gains or losses arising from the use of this information.