Dispute arises over fired workers
About 3,000 workers went on strike last July in Sudbury over pensions, bonus issues and contract language.
More recently, the two sides have also fought over the fate of nine workers who were fired during the strike.
The workers, represented by the United Steelworkers union, want any new contract deal to include a provision to allow the dismissed employees to try to get their jobs back.
Kevin Burkett, the mediator who has shepherded the two sides through tentative talks, said a dispute over "adjudicative avenues available to 8 of the 9 employees" had caused a deadlock.
"I have concluded that additional mediation efforts would not resolve this issue. Accordingly, I am terminating the mediation as of today," Burkett, who was appointed by the province of Ontario, said in an e-mailed statement.
The fact that the two sides were discussing the workers suggests progress on the other issues, as the Ontario Labor Relations Board in May ruled the two sides should consider the fired workers only after resolving the other issues.
A separate strike at Vale's Voisey's Bay nickel mine in eastern Canada began last August.
The Sudbury and Voisey's operations combined typically produce about 10 percent of the world's nickel, as well as sizable amounts of copper, cobalt, and precious metals.
— Reuters