Port workers in Chile have ended a nearly three-week-long strike that paralyzed shipments of copper, one of the South American nation\'s primary industries, labor organizers said on Saturday. \"As of now, workers are free to resume working,\" read a statement issued by the Chilean Port Workers Union. Workers said they reached an accord with the private Ultraport firm, which runs the port in Mejillones in northern Chile, allowing them at least half an hour for lunch and improved benefits. Labor Minister Evelyn Matthei took part in the negotiations that led to the agreement to end the strike, which was reached late Friday. The work stoppage had spread to another eight Chilean ports, blocking shipments of some 9,000 tonnes of copper each day, along with some fruit exports. The world\'s biggest copper producer, Chile churns out 5.6 million tonnes of the metal each year, roughly a third of global production.