Talks between Vale SA and striking nickel miners at Sudbury, Ontario, Canada, broke down after six days of efforts to renew a labour agreement.
The company and the United Steelworkers union resumed talks late last month at the request of a mediator appointed by the Ontario provincial government to help find a resolution to the strike, which began 13 July 2009.
The failed talks have sparked protests and blockades at the Clarabelle mill and Coleman mine, which the company has been operating during the strike.
United Steelworkers director Wayne Fraser said the union aims to start another round of labour talks soon.
Vale SA's Sudbury smelter has been operating at 50% of its capacity since January 2010.
A total of 3,100 workers are on strike at the Sudbury mining and milling operations, as well as Vale's Port Colborne, Ontario, refinery over pension, bonus and contract language issues.