About 400 workers at one of the Ottawa Valley's oldest and biggest manufacturing plants are back to work after five weeks on the picket lines.

Employees at Haley Industries near Renfrew returned Thursday to making magnesium and aluminum casings for the aerospace industry.

They said they were on strike because they weren't seeing the benefits of a booming business and were upset with a proposed 15 cent pay raise.

Instead, their new three-year contract includes a raise of 82 cents an hour and a stronger pension.

The plant in Haley Station has been making parts for 60 years.