Cameco Corp. temporarily halted production at its Cigar Lake uranium mine in northern Saskatchewan on Wednesday after a sulphuric acid plant failure at the Orano McClean Lake mill disrupted ore processing.

Orano Canada, Cameco’s joint venture partner that operates the mill, shut down the acid plant for repairs after encountering operational issues.

While Orano waits for replacement parts, it is exploring alternative acid supply sources.

Cameco, which owns a 57.4% stake in Cigar Lake, said limited ore storage capacity at the mine left it with no choice but to suspend mining.

"We have temporarily suspended mining activities until sufficient acid is available to allow milling to resume at McClean Lake," Cameco said in a statement.

The company expects the mill to return to operation in approximately two weeks and does not anticipate the disruption will affect its 2026 production outlook for Cigar Lake. The mine was projected to produce between 17.5 million and 18 million pounds of uranium concentrate this year.

"There is a risk that the repairs to the acid plant take longer than planned and that mining at Cigar Lake is unable to resume on the expected schedule," Cameco warned. "Depending on the duration of any additional delays, our 2026 production outlook could be impacted".

The suspension comes just one month after Cameco and Orano increased their joint ownership of Cigar Lake, acquiring TEPCO Resources Inc.'s 5% participating interest for approximately $81.5 million.