Glencore (lon: Glen), a mining and commodities trader, will close its Brunswick lead smelter in New Brunswick province by the end of this year because it has become "uneconomical" since it was closed six years ago.

The plant employs about 420 people to process lead / silver concentrate, zinc smelter byproducts and various recycled materials, including batteries and lead glass.

Glencore plans to invest up to $64 million to build an acid plant there.

The first phase, worth about $20 million, was completed but was cancelled in August due to a contract dispute with union workers, including safety issues.

Employees representing more than half of the smelter's employees and the United Steelworkers (USW) blocked Glencore's three plants in the Montreal area, starting with the company's Raglan mine headquarters in Laval.

They say they have been fired since April 24 in a contract dispute over security.

Chris eskdale, head of zinc and lead assets at Glencore, said in a statement: "we have fully evaluated all options and come to the inevitable conclusion that this smelter is not sustainable at all."

Eskdale noted that the labor dispute had nothing to do with the decision to close the Atlantic plant in Canada, adding that the company intended to provide pension, severance and reemployment support services to all employees as part of the closing agreement between the two parties.

The Brunswick smelter opened in 1966. (From CCMN)