Workers at the world\'s third largest copper mine went on strike Monday, accusing management of Chile\'s Collahuasi mine of reneging on agreements that ended a work stoppage in October, the miners\' union said. It was the third strike in a year, putting at risk Collahuasi\'s 500,000-ton annual output, which is three percent of the world\'s total. Collahuasi is owned by Xstrata of Switzerland and Britain\'s Anglo American. This year work at the mine was briefly paralyzed on July 30 and October 29, but production has so far not been significantly affected. \"We report that today Monday November 24, at the start of the morning shift, the Collahuasi workers began a strike due to failure to fulfill agreements established by the company in the October 29 action,\" the union said in a statement. \"As a union we have been saying for a long time that the company has been unable to resolve conflict after conflict at the work sites, causing a strong accumulation of tension between workers and the company that have hurt labor relations,\" it said. Chile is the world\'s biggest copper producer, accounting for a third of total production.