MONTREAL -- Tembec Inc. has ceased production at its lumber mill in Temiscaming after workers went on strike late Wednesday.

The Quebec-based pulp, paper and lumber producer says 650 unionized employees have walked off the job at the facility.

An additional 200 workers employed at the mill are not unionized.

The union and the company have been in negotiations since August 2014. Their four-year collective agreement expired on Sept. 30.

The company also said the closure will delay the installation of a boiler and turbine at the mill, which was expected to be completed by mid-December.

Tembec is a manufacturer of forest products with operations in Canada and France. It employs approximately 3,500 employees and has annual sales of approximately $1.6 billion.