Cameco announced on August 27 that, in response to receiving a strike notice from the United Steelworkers Local 8914, the company had initiated a shutdown of its McArthur River mine-regarded as the world’s largest uranium mine-and Key Lake mill operations and will cease production at those sites.

The union, said Cameco, had advised the company of its intention to commence strike action, effective 12:01 a.m. on August 30. In response to the strike notice, Cameco issued a lockout notice effective 12:01 a.m. on August 30 to “assure a safe and orderly shutdown of its facilities.” Cameco said it had continued to meet with the union during the 72-hour notice period.

The work stoppage involves approximately 535 unionized employees at the two operations. Contract negotiations began in November 2013. The previous four-year contract expired December 31, 2013. In July, the company and union jointly applied for conciliation under the Canada Labor Code.

Cameco said a labor disruption was not expected to affect the company’s 2014 uranium delivery commitments to customers, as it can draw on a variety of supply sources including primary production, and existing purchase commitments and inventories.

Cameco is one of the world’s largest uranium producers, accounting for about 15% of the world’s production from mines in Canada, the U.S. and Kazakhstan.

In 2013, Cameco reported that McArthur River/Key Lake exceeded the company’s production target by 4%, achieving a total of 20.1 million lb. At that time, the company also said that it would continue its program to work toward increasing McArther River’s annual production to 22 million lb/y by 2018. Over the course of the multiyear project, it intends to expand the freeze plant and electrical distribution systems; improve the dewatering system and expand water treatment capacity; and increase ventilation by sinking a fourth shaft at the northern end of the mine.