Hundreds of workers at the Compass Minerals salt mine in Goderich walked off the job Friday afternoon.

In total, 341 miners, electricians and hourly employees are involved in the strike action.

The company and union have been in contract talks since March. Union leaders say seniority, overtime and benefits are among the major outstanding issues.

In a statement from Compass Minerals the company said:

“While we are disappointed Unifor has chosen to strike, it remains Compass Minerals’ goal to negotiate a collective agreement that focuses on the safety of our employees and represents the current operational environment of the Goderich Mine,” said Compass Minerals’ Anthony Sepich, senior vice president, salt. “Our employees are essential for the success of our organization and the company plays an important role in the Goderich community. We are committed to work with the union to negotiate an agreement that achieves this goal.”

Compass Minerals says work will continue at the site with other employees.

Forty-eight of the mine’s employees were laid off in February.