By Fabian Cambero
SANTIAGO, June 14 (Reuters) - More than 3,000 unionized workers at Codelco's sprawling Chuquicamata copper mine walked off the job early Friday morning after failing to reach a labor deal earlier this week with Codelco COBRE.UL, the world's top producer of the metal.
Chuiquicamata unions 1, 2, and 3 rejected a contract offer from the state miner on Wednesday, saying it did not meet key demands, including an adequate health care plan, fair treatment of workers and retirement benefits. The three unions represent 80% of the mine's workforce.
Union leaders told reporters the strike kicked off with the first shift of the morning at 5 a.m. local time (0900 GMT). It was not immediately clear how the walkout was affecting production.
Waving black and Chilean flags, a caravan of workers traveled the dusty desert roads before dawn from the regional hub of Calama to the doorstep of the mine to initiate the strike.
Codelco has said its last proposal was the best it could offer "while still being responsible to the country, considering the transformation that both the company and the Chuquicamata division are undergoing."
Codelco is seeking to transform the century-old deposit at Chuquicamata into an underground mine and part of a 10-year, $39 billion overhaul of Codelco's key operations. It is seeking to maintain output despite rapidly falling ore grades at its deposits.
(Reporting by Fabian Cambero; writing by Dave Sherwood; Editing by Jeffrey Benkoe)