SANTIAGO, Jan 11 (Reuters) - Unionized workers at global miner BHP Billiton's Cerro Colorado copper mine in Chile went on strike on Monday after contract negotiations failed, union director Gustavo Tapia told Reuters.
Workers "abandoned the mine, and the strike became effective as of 8 in the morning (1100 GMT)", said Tapia.
The relatively small Cerro Colorado mine produced 55,600 tonnes of copper from January to September 2015, according to Chilean state copper commission Cochilco.
"It's too premature to make a precise analysis but considering unionization rates (at the mine) of around 100 percent, it's unlikely there will be production," said Tapia.
The union, which represents nearly 700 workers at Cerro Colorado, rejected the company's last proposal of a real wage increase of 1 percent.
BHP Billiton was not immediately available to comment. (Reporting by Fabian Cambero; Writing by Anthony Esposito; Editing by Jeffrey Benkoe)