The author of an article claiming that Rio Tinto was able to overcharge the Chinese government more than US$1 billion for iron ore over the past six years admitted he had nothing to do with the case, the Wall Street Journal reported. Government employee Jiang Ruqin claimed that he wrote the essay out of his "sense of responsibility as a Chinese national." Canberra remained unfazed by the accusations. "The [Australian] government has always said the Stern Hu case was complex and involved serious allegations," a spokeswoman said. Rio Tinto’s stock, however, fell 3.3% to A$48.93 (US$40.88) Monday even as the Australian market rose 0.1%. Rio’s shares had been rising recently on resurgent commodity prices.