A senior Chinese official on Wednesday attacked the planned iron ore joint venture between Rio Tinto and BHP Billiton, raising expectations that Beijing may use its antitrust law to try to scupper the “monopolistic” deal. Chen Yanhai, head of the raw material department of China’s ministry of industry and information technology, told state media that the joint venture “has an obvious colour of monopoly” and should be subject to China’s anti-monopoly laws.