Xinhua reported over night that the Shanghai court had accepted the charges against Hu, along with similar charges against fellow Rio employees Wang Yong, Ge Minqiang and Liu Caikui.

The news agency quoted prosecutors as saying the four are accused of "taking advantage of their position to seek profit for others, and asking for, or illegally accepting, huge amounts of money from Chinese steel enterprises".

That accusation appears to be a significant shift of ground from prosecutors, as previous Xinhua reports have indicated Hu and his colleagues would be accused of offering bribes to Chinese steel mill officials, in exchange for commercially sensitive information.

But Xinghua also reported that prosecutors would allege that the four “lured the Chinese enterprises' heads with promises, or through other illegal means, to obtain the steel companies' commercial secrets on multiple occasions, causing ‘extremely serious consequence’ for the companies”

The four Rio employees were detained by officials in Shanghai on July 5 last year and were officially arrested and charged five weeks later.

Investigations wrapped up in January, and the case was handed over to local prosecutors, who have taken until now to formally lay charges in a Chinese court.

Neither Rio Tinto nor the Australian federal government had issued public comments on the move at the time MiningNews.net went to press.

The charges come a week after Rio Tinto moved to repair its strained relationship with the Chinese government by appointing Ian Bauert as its new China operations head.

Bauert, who speaks fluent Chinese, set up the company’s first office in China 25 years ago.

Xinghua reported Bauert’s appointment was widely seen in China as a step to normalising relationships between the mining giant and its largest customer.