NexGen Energy Crosses the Rubicon: Construction Begins on the World's Largest Uranium Mine

With final federal approval in hand and shovels ready to move in July 2026, Leigh Curyer's NexGen is transitioning from developer to builder at Rook I while a nearby discovery threatens to make the project even larger and the company remains the purest high-grade leverage to rising uranium prices.

On March 5, 2026, the Canadian Nuclear Safety Commission issued NexGen Energy the final federal licence to prepare the site and construct its Rook I project in Saskatchewan’s Athabasca Basin. Fourteen days after the conclusion of the Part 2 hearings, the decision arrived. For Leigh Curyer, NexGen’s founder, president and chief executive, the speed was no accident. “It reflects the quality of the submission and the incredible support from all of the community stakeholders,” Curyer told The Deep Dive. The four-day public hearings had showcased detailed technical work and broad local buy-in. There were, in his words, “no loose ends. ”That approval marked the end of a seven-year permitting journey and the beginning of something rarer in the uranium sector: the actual construction of a large, high-grade, Western-world mine. NexGen has already made its final investment decision. Pre-construction work—a $100-million program of camp accommodations, an airstrip and road upgrades—was scheduled for completion in June. Official construction was set to commence in July 2026.Forty-eight months later, if the schedule holds, Rook I will begin generating the cash flows that Curyer believes will place NexGen among the top ten mining companies in the world by profitability.

A Project Built for Execution

The long permitting period, often criticized for its duration, delivered an unusual benefit. NexGen used the years to stress-test every element of the build. More than 400,000 metres of drilling have defined the overburden and basement rock. The company has planned the 48-month construction schedule down to the weekly level, identifying exactly which teams and contractors will execute each phase.Shaft sinking is budgeted at an average 2.2 metres per day. Curyer considers the overall timeline already condensed and sees little realistic scope for material acceleration without compromising safety or long-term performance. The most variable ground—the first roughly 100 metres of overburden—will be traversed early. Once the shafts reach competent basement rock, schedule and cost risk drop sharply. Rook I is designed around the Arrow deposit, one of the highest-grade, large-scale uranium resources on the planet. Probable reserves stand at 239.6 million pounds grading 2.37 percent U?O?. The feasibility study contemplates average annual production of nearly 29 million pounds in the first five years—enough to make it the largest uranium mine globally.

Maximum Leverage to the Uranium Price

While construction ramps up, NexGen has begun laying the commercial foundation. In 2025 the company signed offtake agreements covering 2 million pounds per year for the first five years of production—10 million pounds in total—all with U.S. counterparties. These contracts are structured with extremely high exposure to the spot price at the time of delivery (approximately 99 percent on average). At a uranium price of $86 per pound, NexGen would realize about $85. At $125, the realized price would be approximately $122. The contrast with established Western producers is stark. Many of those companies remain locked into legacy contracts that deliver realized prices in the low $60s for years to come. Curyer is explicit about the strategy: any future offtake will remain heavily tied to the market price at delivery. Five additional contracts covering U.S., Asian and European utilities are already in advanced negotiation. Inbound interest surged again after the March 5 approval. “Finding places for the offtake is certainly not the challenge,” he said. “There’s extraordinary demand for new mine supply.”The result is a corporate profile Curyer describes as “the world’s most leveraged company to the price of uranium.”

The PCE Wildcard

Three and a half kilometres from Arrow, NexGen is advancing the PCE discovery. Drilling in 2025 and the winter 2026 program has revealed a zone that mirrors Arrow’s key characteristics: broad mineralization hosted entirely in competent basement rock, with an ultra-high-grade subdomain. The system remains open in every direction. Curyer believes PCE has already crossed the economic threshold, particularly because the heavy capital infrastructure—shafts, mill, surface facilities—will already exist at Arrow. A conceptual underground tunnel could link the two deposits, allowing PCE material to be hoisted through Arrow’s production shaft. An amendment to the production licence would then be sought. Further drilling will quantify the opportunity, but the early evidence suggests Rook I may ultimately be larger than the already industry-leading plan.

What Success Looks Like Over the Next Twelve Months

For investors tracking the story, Curyer offered a clear near-term checklist:

• Construction is fully underway and progressing through the early civil and shaft-sinking phases.

• Additional drill results from PCE continue to expand the new zone.

• Further offtake agreements are signed, all maintaining strong leverage to spot prices at delivery.

• The uranium price itself grinds higher, amplifying the value of every uncommitted pound and every share of the most price-sensitive large-scale developer in the sector.

Canada, Curyer argues, now has a flagship project capable of demonstrating what a world-class, responsibly developed uranium mine looks like. In a global market desperate for diversified, geopolitically secure supply, Rook I is moving from promise to steel and concrete on a defined 48-month clock.The permitting marathon is over. The construction race has begun. For a sector that has waited more than a decade for the next truly generational Western uranium mine, the starting gun has sounded in northern Saskatchewan.

Disclaimer: 

This article is for informational and educational purposes only. It does not constitute investment advice, a recommendation to buy, sell, or hold any securities, or a forecast of production timelines, costs, uranium prices, or share performance. Mining equities involve significant risk, including the potential for complete loss of capital. Readers must conduct their own due diligence and consult qualified professionals. The author and publisher are not registered investment advisors.