SANTIAGO, Chile (AP) â¿¿ Contract workers at the private Collahuasi copper mine in northern Chile say they have paralyzed operations to demand better compensation and work rules. The mine is owned by London-based miner Anglo American PLC and Japanese investment house Mitsui & Co. Mine representatives were not available to describe the impact on production. Contract workers number about 4,400 and account for three out of four jobs at Collahuasi. The mine produced 535,000 metric tons of copper last year. Chilean Mining Labor Federation President Pedro Marin said Sunday the mine is running on emergency shifts and that all accesses have been blocked by contractors. Mine manager Juan Carlos Palma said the company is open to discussions.