Welcome to Nuclear Update.

A few weeks ago, I published the ⚛️ Inside a Uranium Discovery episode (aka the uranium treasure hunt episode). Airborne surveys, weird rocks, pathfinder chemistry, and lots of drilling. Drill, baby, drill.

Since that post, F3 Uranium (TSX-V: FUU, OTCQB: FUUFF) has announced an initial Mineral Resource Estimate for JR Zone, and they’re back supporting Nuclear Update with this sponsored feature.

Today is the sequel: welcome to spreadsheet season, ’tis the season for pounds and grades on the table.

🕵 MRE 101: The Moment the Story Gets Audited

A Mineral Resource Estimate (MRE) is the mining industry’s version of going from “trust me bro” to “here are the receipts”.

Up to this point, exploration news is usually drill-highlights, a few maps, and a lot of hopeful interpretation. Useful, but hard to compare across projects and companies.

An MRE is different. It’s a structured estimate prepared by independent qualified experts who sign off on it, using drilling data and geological modeling, to quantify how much uranium is likely in the ground, what grade it is, and how confident the estimate is.

It becomes the baseline companies use to plan the next drilling, raise capital, and start moving toward real engineering work.

🧮 What Counts (And What Doesn’t)

An MRE forces the company and the independent consultants to take all that drilling and geology, build a 3D model, and then answer a more grown-up set of questions.

First, what’s actually mineable?

That’s where the terms resource and reserve come in.

A mineral resource is all of the mineral in the deposit, including parts that are inaccessible or not feasible to extract for economic, environmental or technological reasons.

A mineral reserve is the portion of the resource that has been proven to be economical to mine, with defined costs, recoveries, and operating studies.

In other words, a resource tells you what you have, a reserve tells you what you can mine.

Second, how confident are we in the numbers?

MREs classify material by confidence, a function of drilling density, geological continuity, and how consistent the grades are.

Inferred is early stage. The geology is promising, but there’s still meaningful uncertainty.

Indicated is higher confidence. The data supports a more reliable estimate, and it’s often the level where serious engineering studies start to become meaningful.

Measured is the highest confidence, typically requiring tighter drilling and stronger continuity.

Most deposits start with a lot of inferred material and slowly “upgrade” as more drilling fills in the gaps.

Third, how concentrated is the uranium, and what rock is “good enough” to count?

That is the job of grade and the cut-off grade. Grade is simply how much uranium is in the rock (usually expressed as % U₃O₈). Higher grade means fewer tonnes to process for the same pounds, potentially smaller mining footprints, and often more resilience if costs rise. Two deposits can have the same number of pounds on paper, but the higher grade one usually has a very different quality profile once you start thinking about how it could be mined.

But an MRE does not count every trace of uranium it finds. It draws a line. The cut-off grade is that line, the minimum grade that makes sense to include based on the assumed mining method, costs, metallurgical recovery, and a reference uranium price. Anything above the cut off gets counted as part of the resource, anything below it does not.

So, when you read an MRE, you’re reading more than “X million pounds”. You’re reading a structured statement about the deposit’s size, quality, and confidence, and a roadmap for what the company needs to do next to move from discovery to development.

⏮Previously on Nuclear Update

If you missed episode one: F3 Uranium is a Canadian uranium explorer focused on the Athabasca Basin, Canada, the world’s best address for high grade uranium. Their flagship is the Patterson Lake North (PLN) Project, a large, underexplored land package where the JR Zone deposit is located and the newer Tetra Zone is being expanded.

JR Zone was the 2022 discovery that put PLN on the map. Tetra is the newer play, a fresh discovery zone about 13 km south, in an area that had seen little modern drilling.

The company is led by an award winning team with a track record in the Basin, including the high-grade Patterson Lake South (PLS) discovery in 2012 and previous uranium company build-and-exit experience, including deals involving Denison and Paladin (with the Paladin transaction publicly discussed at roughly $1.1 billion).

On the balance sheet side, F3 has around 26 million dollars in the bank, with roughly half of that budgeted for drilling. That gives the company room to run drilling programs on Tetra and elsewhere on the project throughout calendar 2026 without needing to come back to the market immediately. A small but important detail for anyone who has sat through too many dilutive financings in past cycles.

📣 What F3 Just Announced

Here’s the new part since episode one: F3 has now announced the first set of properly audited numbers on its 100% owned JR Zone. You can read the full announcement here.

The headline looks like this: 11.8 million lbs U₃O₈, Indicated at 4.39%, and inside that, a High Grade Domain of 10.8 million lbs at 12.23%.

Three more things worth underlining:

First, this maiden resource estimate ranks the JR Zone deposit as one of the highest grade zones in the Athabasca Basin along with Hurricane, Cigar Lake, McArthur and Phoenix.

Second, this estimate is for the basement shear hosted JR Zone deposit exclusively, and it is entirely classified as Indicated. Not a mix of inferred and indicated, not an early stage “rough draft,” this is a higher confidence bucket right out of the gate.

Third, this is based on real work. SLR estimated the resource using drill hole data from 89 drill holes totaling 29,414 meters.

And the standard but important caveat applies: mineral resources are not mineral reserves, and economic viability has not been demonstrated at this stage.

Next milestone is the NI 43 101 Technical Report, which the company says will be filed publicly within 45 days. That’s the full “show your work” document behind the headline numbers, it lays out the model, assumptions, and methodology in detail.

⚛️ Wrapping Up

Exploration is fun because it’s a treasure hunt.

The JR Zone MRE is the first time F3’s discovery shows up as a standardized, third-party estimate: pounds, grade, and confidence, not just highlight reels. And the high-grade core is the kind of detail that changes how people think about the quality of a deposit. It turns a good story into something you can track, compare, and build a real development roadmap around.

The next checkpoint is the technical report. After that, the question becomes simple in the best way: how far can F3 take this, with JR now quantified and Tetra still adding upside.

– Fredrik

For more information on F3 Uranium’s work across the Athabasca Basin, visit their website at f3uranium.com or contact their investor relations team at [email protected]

Disclosure: This Deep Dive was created in collaboration with F3 Uranium, which sponsored this post. All analysis and opinions are those of Nuclear Update.

DISCLAIMER: None of this is financial advice. Nuclear Update is for informational and educational purposes only, it’s here to help you understand the world of uranium, energy, and the markets that orbit them, not to tell you what to buy or sell. Nothing in this article should be taken as a recommendation or solicitation to make any financial decision. Always do your own research, double-check sources, and talk to a licensed professional before making investments. Markets move fast, opinions change, and yes, sometimes even Fredrik gets things wrong.