The miner, which has already settled for $1.2 million with the Australian Securities and Investments Commission, has vowed to vigorously defend the class action.
The company also said that ore from its Cigar Lake mine, in Canada's Saskatchewan, would not be milled until early 2015, instead by the end of the year.
The world’s second-largest mining company’s produced 139.5 million metric tons of iron ore in the six months through June, while its shipments rose 20% to 142.4 million tons.