Name of the Project
Rook I uranium project.

Location
Rook I is a high-grade underground uranium mine and mill under construction in the south-western Athabasca basin, in Saskatchewan, Canada.

Project Owner/s
Canadian exploration and development NexGen Energy owns 100% of the project.

Project Description
The project hosts the Arrow deposit, which hosts measured and indicated mineral resources of 256.7-million pounds of uranium contained in 3.75-million tonnes grading 3.1%.

The 2021 feasibility study supports an initial mine life of 10.7 years. The project is permitted to produce up to 30-million pounds a year of uranium.

Average life-of-mine production is estimated at 21.7-million pounds a year of uranium.

Access to the underground Arrow deposit will be through two shafts, an 8-m-diameter production shaft (intake air) and a 5.5-m-diameter exhaust shaft (second egress). Access to the workings will be from the production shaft.

Conventional longhole stoping will be used for production. Automated and tele-remote equipment will be used to extract ore and move it to the hoist.

Nominal mill capacity is 1 300 t/d of ore.

The key infrastructure contemplated includes:

• underground infrastructure, including materials handling systems, maintenance facilities, a fuel bay, an explosives magazine, ventilation, a paste backfill and a paste tailings distribution system, electrical and communications facilities, underground water supply and dewatering facilities.
• an underground tailings management facility.
• surface support infrastructure for the mine, including headframe and hoist facilities, a surface explosives magazine and ventilation fans.
• surface support infrastructure for the mill, including a process plant, a solvent-extraction plant, an effluent treatment plant and an acid plant.
• site support infrastructure, including an accommodation camp, liquefied natural gas (LNG) facilities, an LNG power plant, mine and mill dry facilities, analytical and metallurgical laboratory and maintenance, as well as warehouse and security buildings.
• a surface ore-storage stockpile facility, as well as waste-rock storage facilities for potentially acid-generating, nonpotentially acid-generating and special waste materials.
• water management facilities, consisting of two site water runoff ponds, six contact water process ponds, a potential acid-generating stockpile runoff collection pond, and conveyance and diversion structures.
• domestic and/or industrial waste management areas.
• an airstrip.

Potential Job Creation
About 459 full-time jobs.

Net Present Value/Internal Rate of Return
The project has an after-tax net present value, at an 8% discount rate, of C$6.32-billion and an internal rate of return of 45.2%, with a payback of one year, based on a uranium price of $95/lb.

Capital Expenditure
C$2.2-billion.

Planned Start/End Date
Construction started in August 2026; the build is expected to take 48 months.

Latest Developments
NexGen officially marked the start of construction on August 13, 2026, following final federal approval in March. Site work includes earthworks, shaft and mill pads, and shaft preparation.

Detailed engineering and long-lead procurement are advancing, with critical-path contracts in place.

Key Contracts, Suppliers and Consultants
None stated.

Contact Details for Project Information
NexGen Energy, tel +1 306 954 2275 or email info@nxe-energy.ca.