The China Iron and Steel Association (CISA) criticized plans by Australian miner BHP Billiton to revise iron ore contract pricing, the Melbourne Herald Sun reported, citing reports in Chinese state media. BHP had proposed the use of a price index to set ore prices, rather than through traditional yearly agreements between suppliers and customers. "The index is improper and unfair," said the CISA in a statement. "It’s not good for long-term stable co-operation between the supply and demand sides, so we firmly oppose it." Rival firms Rio Tinto and Vale have already reached agreements with Chinese steelmakers, leaving BHP Billiton the only one of the world’s top three miners yet to reach an agreement with China. Baosteel, China’s largest steelmaker, earlier agreed to pay up to 96.5% more for Rio Tinto’s ore, while Vale announced price hikes of between 65% and 71%.