McArthur River/Key Lake
- McArthur River/Key Lake, located in northern Saskatchewan, Canada, are the world's largest high-grade uranium mine and mill.
- In service since 1999 and 1983 respectively, Cameco operates the ISO 14001 certified operations, which have collectively produced 583 million pounds using a variety of mining methods.
Operation
McArthur River Reserves
2025 Q4 Update
- Production
McArthur River Production
Cameco's Share (million lb)
Three
months ended
December 31Year ended
December 312025 2024 2025 2024 2025
Plan2026
Plan23.3 3.6 10.5 14.2 9.8 to 10.51 10.0 to 11.5 1 In August, we changed our outlook for production at McArthur River/Key Lake to produce between 14 million and 15 million pounds (100% basis) in 2025 (previously expected 18 million pounds).
2 Production ranges are rounded to the nearest half-million.
Total packaged production from McArthur River and Key Lake in 2025 was 15.1 million pounds (10.5 million pounds our share), compared to 20.3 million pounds (14.2 million pounds our share) in 2024. Planned production was not achieved due to a shortfall in mine production at McArthur River as disclosed on August 28, 2025.
The McArthur River mine was unable to fully mitigate the impacts of the delayed development and ground freezing in new mining zones. The mine’s performance was also impacted by availability of equipment and certain workforce skills.
The Key Lake mill saw notable improvements in its operational performance in 2025, with the site becoming more familiar and experienced with new equipment and control system upgrades. In addition, the systematic understanding of process bottlenecks and efforts to remove or decrease their impacts allowed Key Lake to optimize the mill throughput rates. Despite these improvements, overall production for the year was constrained by a six-week unplanned shutdown in the fall of 2025, resulting from a lack of ore feed from McArthur River, which limited the mill’s ability to consistently operate at planned rates and ultimately impacted the achievement of production targets.
- Exploration
Underground exploration at McArthur River continued in 2025 with the focus areas being in-fill drilling of zones A and B as well as surface exploration drilling on northern brownfield drill targets.
- Planning for the future
We plan to produce from 14 million to 16.5 million pounds (100% basis) in 2026; our share is approximately 10.0 million to 11.5 million pounds. The production rate is currently constrained by limited ore feed supply as a result of delays in new mining areas at McArthur River. In 2026, we expect to bring zone 1 into production which will notably improve the number of mining fronts available. In addition, we will continue to advance zone 4 south development while adding to our workforce and replacing mobile equipment. We also plan to continue with our underground exploration activities in 2026.
- Labour Relations
The collective agreement with the United Steelworkers Local 8914 expired in December 2025. As such, there is a potential risk of a labour dispute impact in 2026 if a new contract agreement cannot be reached.
Environment & Safety
Worker safety, environmental monitoring and proper decommissioning, after mining is completed, are of the utmost importance to Cameco.
Reserves & Resources
Our mineral reserves and resources are the foundation of our company and fundamental to our success.
Caution about Forward-Looking Information
This page may contain forward-looking information that is based upon the assumptions and subject to the material risks discussed on page 2 of Cameco's most recent Quarterly MD&A.
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