Uranium Ore Grades & Deposit Types: How to Read a Resource Statement

60-second answer: Uranium ore grade measures how much uranium is packed into the rock, quoted either as a percentage of U3O8 (or U) or in parts per million (ppm) — where 1% U3O8 equals 10,000 ppm. "High grade" is relative: the world's average mined grade sits well under 1%, while Canada's Athabasca unconformity deposits can run above 15% U3O8, roughly 100 times richer. Grade multiplied by tonnage gives you contained pounds, the number that actually matters. A resource statement layers on cutoff grade, confidence categories (measured, indicated, inferred), and a reporting standard like NI 43-101 or JORC. Learn the vocabulary once and every project on our projects page becomes readable. This is not investment advice.

Every uranium project pitch leans on a resource statement, and those statements are dense with jargon: grades in odd units, four different confidence tiers, cutoff assumptions, a reporting-code acronym. This guide decodes all of it so you can compare a NexGen against a Kazakh ISR field without taking the marketing at face value.

What "grade" actually means

Grade is a concentration — the fraction of the rock that is uranium. It is the single most important economic lever in mining, because a richer rock yields more metal per tonne dug, hauled, and processed.

Uranium grade is quoted two ways:

• Percentage — usually %U3O8 (triuranium octoxide, the standard product form) or sometimes %U (elemental uranium). U3O8 is about 85% uranium by weight, so a %U figure is a bit lower than the same rock's %U3O8 figure. Always check which one a report uses.
• Parts per million (ppm) — common for low-grade deposits, where percentages get awkwardly small. The conversion is simple: 1% U3O8 = 10,000 ppm U3O8. So a 0.05% deposit is 500 ppm; a 200 ppm deposit is 0.02%.

Grade is not the same as the amount of uranium in the ground. A tiny high-grade lens can hold fewer total pounds than a vast low-grade blanket. That is why grade always travels with tonnage.

Grade × tonnage = contained pounds

The number that pays for a mine is contained pounds (or tonnes) of U3O8, and it comes from one multiplication:

tonnes of ore × grade = contained metal.

For example, 10 million tonnes at 0.10% U3O8 contains 10,000,000 × 0.001 = 10,000 tonnes of U3O8, which converts to roughly 22 million pounds (1 tonne ≈ 2,204.6 lb). Change either input and the answer moves proportionally.

This is why you cannot judge a deposit on grade alone. High grade lowers the cost of extracting each pound and shrinks the footprint you have to mine, but a modest tonnage caps the total prize. Low grade can still be world-class if the tonnage is enormous and the rock is easy to mine — Namibia's big open pits and some ISR fields work exactly this way. To turn a grade quickly into pounds for any deposit you are looking at, use our grade-and-tonnage converter on the projects page.

What counts as "high grade"

Because the world average mined grade sits well below 1% U3O8, context matters enormously. Rough tiers used in practice:

The Athabasca Basin is the outlier that shapes the whole conversation. Its unconformity deposits can grade above 15% U3O8 — roughly 100 times the sub-1% world average. That extreme richness is why a comparatively small Canadian orebody can rival much larger low-grade deposits on contained pounds, and why grade outliers like NexGen's Arrow draw so much attention. We break that project down in our NexGen Energy (NXE) guide.

Deposit types (and why grade tracks the type)

Grade is mostly a function of geology. The main uranium deposit types each carry a characteristic grade range:

• Unconformity-related — forms where old basement rock meets younger sandstone. The richest deposits on Earth: Athabasca (Canada) and the Alligator Rivers region (Australia). Grades from a few percent to well over 15% U3O8, but often deep and technically demanding, sometimes needing freezing and remote mining.
• Sandstone / roll-front — uranium precipitated where oxidised, uranium-bearing groundwater hit a chemical boundary in permeable sandstone. Low grade (hundreds of ppm to a few tenths of a percent) but well suited to in-situ recovery (ISR), which dissolves uranium underground and pumps it up — cheap, low-footprint. Dominant in Kazakhstan, the US, and Uzbekistan.
• Breccia complex — the giant of the group. Australia's Olympic Dam is a huge iron-oxide-copper-gold system where uranium is a low-grade by-product of copper mining. Grade is marginal on its own, but the sheer scale and shared mining cost make it economic.
• Calcrete — surface deposits where uranium concentrated in near-surface calcium carbonate, as at Namibia's Langer Heinrich. Low grade, but shallow and cheap to open-pit.

Other types (vein, intrusive, phosphate by-product) exist, but these four cover most of what you will see on a resource map. The takeaway: when someone quotes a grade, the deposit type tells you whether that grade is good, average, or marginal for its class.

Cutoff grade: the line that price moves

Not every gram of uranium in the ground gets counted. A resource is reported above a cutoff grade — the minimum grade at which mining a tonne of rock is expected to pay for itself. Rock below the cutoff is waste, at least at today's assumptions.

The crucial point: the cutoff grade depends on the uranium price. A higher assumed price lowers the cutoff, because lower-grade rock becomes economic to process — which can grow the reported resource without a single new drill hole. A lower price does the reverse. This is why two resource statements on the same deposit can differ, and why you should always check the price assumption and cutoff behind a headline pounds figure. We define the term in full on our cutoff-grade glossary entry.

The confidence ladder: resources vs reserves

A resource estimate is a geologist's model of what is in the ground, sorted by how confident that model is. Two families, from least to most certain:

Mineral resources — geologically defined, not yet proven economic to mine:

• Inferred — lowest confidence; implied from limited drilling. Indicative only, and generally cannot be used in an economic study.
• Indicated — enough drilling to estimate grade and tonnage with reasonable confidence.
• Measured — highest resource confidence, from close-spaced, high-quality data.

Mineral reserves (or ore reserves) — the subset of measured and indicated resources shown to be economically mineable in a technical study (a preliminary feasibility or feasibility study), after applying mining, processing, and cost factors:

• Probable reserve — from indicated (or sometimes measured) resources.
• Proven reserve — from measured resources; the highest-confidence category of all.

A rule that trips up newcomers: resources and reserves are usually reported separately, and reserves are not additional to resources — they are the economically confirmed portion. Adding the two double-counts pounds. See our resources glossary entry for the fuller picture. When you compare projects, weigh where the pounds sit on this ladder: a large inferred resource is a lottery ticket; a proven-and-probable reserve is bankable.

Reporting standards: NI 43-101 vs JORC

Resource statements are not free-form marketing. Public companies must report under a recognised code so the numbers are prepared and signed off by a qualified professional:

Both descend from the international CRIRSCO template, so their resource and reserve categories line up closely. The practical value is trust: a compliant statement means an independent expert has staked their name to the methodology, the sampling, and the assumptions. A grade or pounds figure quoted without a standard — or from a jurisdiction with weaker rules — deserves more scepticism. We keep a plain-English definition on our NI 43-101 glossary entry.

Putting it together: reading a real statement

When you open a resource statement, run this quick checklist:

1. Which unit? %U3O8, %U, or ppm — and convert to a common basis (remember 1% = 10,000 ppm).
2. What deposit type? It tells you whether the grade is strong or marginal for its class.
3. What cutoff and price assumption? A generous price inflates the resource.
4. Which confidence category? Inferred pounds are soft; proven reserves are hard.
5. Resource or reserve — and are they being double-counted?
6. Under what standard? NI 43-101 or JORC signals a qualified sign-off.
7. Grade × tonnage = pounds — do the multiplication yourself to sanity-check the headline.

Do that and the numbers scattered across our projects page stop being marketing and start being comparable. To connect these deposits to the companies that own them, screen the sector on our uranium stocks page.

Frequently asked questions

What is a good uranium ore grade? It depends on the deposit type, but anything above about 1% U3O8 is high grade against a world average well under 1%. Athabasca unconformity deposits can exceed 15% U3O8 — roughly 100 times average — while sandstone and ISR fields may be economic at only a few hundred ppm because they are so cheap to mine.

How do you convert %U3O8 to ppm? Multiply the percentage by 10,000. So 1% U3O8 = 10,000 ppm, 0.1% = 1,000 ppm, and 0.05% = 500 ppm. To go the other way, divide ppm by 10,000.

What is the difference between a resource and a reserve? A resource is uranium defined geologically (inferred, indicated, or measured), while a reserve is the portion of measured and indicated resources proven economically mineable in a technical study (probable or proven). Reserves are a confirmed subset of resources, not an additional amount.

What does NI 43-101 mean for uranium projects? NI 43-101 is Canada's standard for disclosing scientific and technical information on mineral projects. It requires a Qualified Person to sign off on grades, tonnages, and resource categories, giving investors more confidence than an unregulated figure. Australia's equivalent is JORC.

Why does the uranium price change a deposit's size? Because the reported resource is only the rock above a cutoff grade, and the cutoff depends on the assumed price. A higher price lowers the cutoff, making lower-grade rock economic and enlarging the reported resource — without any new drilling.

This article is for informational purposes only and is not investment advice. Always do your own research.