NexGen breaks ground on Rook I uranium mine in Saskatchewan

NexGen Energy has begun construction at the Rook I uranium project in northern Saskatchewan, starting a four-year build toward a mine expected to produce 30 million pounds of uranium a year. In a market trading at roughly $86 a pound, the Arrow deposit is the largest single supply-side answer the industry has under development — and the only Western mine of its scale with final approvals in hand.

Key facts

• NexGen marked the official start of construction at Rook I, about 155 km north of La Loche in the southern Athabasca Basin.
• The Arrow deposit holds a probable reserve of 239.6 million pounds U3O8 at an average grade of 2.37%, within a 256.7-million-pound Measured and Indicated resource.
• The project received its final regulatory approval in March 2026 and is described by NexGen as the largest development-stage uranium project in Canada.
• About 300 people are on site, with shaft development planned for 2027 and the full 5,840-foot airstrip due by December.
• Former Prime Minister Stephen Harper said the completed project would deliver 20% of the world's uranium supply.

What happened

The groundbreaking brought Indigenous leaders, federal and provincial representatives, investors and contractors to the site on Treaty 8 territory, including Harper, Saskatchewan Premier Scott Moe and Métis Nation–Saskatchewan President Glen McCallum. The project holds Benefit Agreements with all four Indigenous communities identified within its Local Priority Area.

"Today, we transition from demonstrating what this project will be to delivering it," NexGen founder and CEO Leigh Curyer said, calling uranium "one of the world's most strategic resources" as electricity demand rises on artificial intelligence, electrification and energy security.

Physical work is already underway. A Clearwater River Dene Nation-partnered business has crushed and stockpiled more than 575,000 tonnes of aggregate, supporting up to 50 local jobs. The initial 3,000-foot airstrip is commissioned, and expanded accommodations are occupied, according to World Nuclear News.

Curyer's framing put the demand side in view as clearly as the supply side: nuclear energy has become key to meeting "unprecedented" electricity demand from artificial intelligence, advanced manufacturing and electrification, and uranium with it has become strategic. The presence of a former prime minister and the sitting premier at a mine groundbreaking in the remote Athabasca region underlines that Ottawa and Regina now treat uranium the way they once treated potash and oil — as provincial economic policy with global leverage.

Why it matters

The reactor buildout has a fuel problem, and the fuel problem starts at the mine. NNN has tracked the downstream pressure — the HALEU commitments underpinning advanced-reactor pipelines and the fleet-scale offtake agreements now being signed, like TerraPower's eight-reactor arrangements. All of those contracts ultimately presume mines that exist. Rook I is the largest single project in the Western pipeline that now has final approval, broken ground and a dated construction sequence.

The deposit's grade does the economic work. At 2.37% U3O8, Arrow is an order of magnitude richer than most operating mines outside the Athabasca Basin, which is what lets NexGen talk about 30 million pounds a year — a figure that would make one Saskatchewan project larger than several producer countries combined. Whether the market needs all of it at once is a question the four-year construction window will answer.

Background

Arrow was discovered by NexGen in 2014. Per the company's 2021 feasibility study, the ore body lies roughly 300 to 700 metres underground and will be accessed by two shafts — an 8-metre production shaft and a 5.5-metre exhaust shaft providing second egress — using conventional longhole mining, with mill capacity targeted at 1,300 tonnes of ore per day. The project spent more than a decade in exploration, engineering and permitting before the March construction approval cleared the final regulatory gate.

What's next

The watchpoints are sequential and dated: the full airstrip by December, shaft development in 2027, then the production ramp the feasibility study maps over the early 2030s. The strategic question is contracting — which utilities and which advanced-reactor developers lock in Arrow pounds on long terms, and at what price. With fuel security now a stated reason for plant extensions from Spain's Almaraz outward, a sanctioned, financed, construction-stage Athabasca mine is the asset every utility fuel desk is watching.