Cameco shuts Cigar Lake mine on Orano mill disruption

Cameco (TSX: CCO; NYSE: CCJ) says it has temporarily suspended operations at its Cigar Lake mine in northern Saskatchewan, citing disruptions at the McClean Lake mill operated by France’s Orano.

The McClean Lake mill, where the Cigar Lake ore is normally processed, has encountered operational challenges with its sulfuric acid plant that caused it to shut down in order to repair the issue, the uranium miner said in a press release on Wednesday.

Orano is currently working to bring the plant back online and is assessing options to obtain acid supply from an alternative source while it waits for replacement parts to complete the repair, Cameco added.

“With limited ore storage capacity at Cigar Lake, we have temporarily suspended mining activities until sufficient acid is available to allow processing to resume at McClean Lake,” Cameco’s statement reads.

Shares of Cameco were little moved during the early hours of trading despite the operational setback. Trading at about $102 a share in New York, the company has a market capitalization of $44.6 billion.

Two-week stoppage

The company expects the McClean Lake mill to resume in ​about two weeks and does not anticipate an ‌impact ⁠on its 2026 production outlook for Cigar Lake, though it did not rule out a longer-than-expected disruption.

Depending on the duration of any additional delays, our 2026 production outlook could be impacted, it said.

McClean Lake represents one of the world’s largest uranium processing facilities, with an annual production capacity of 24 million lb. in concentrates. It is operated by Orano as its majority owner (77.5%) in partnership with Denison Mines (22.5%). The site is located 750 km north of Saskatoon.

Cigar Lake, situated 70 km southwest of the mill, is the world’s highest-grade uranium mine. Since commissioning in 2014, the operation has produced a total of 174.5 million lb. of yellowcake.