Rio said it was “still operating” in the country, and refused to comment on the withdrawal of its foreign staff.
Rio Tinto’s China team, who the four arrested men worked for, managed operational details of term contracts for iron ore, a key ingredient in steel making, as well as tracking market information.
Rio maintains it has seen no evidence to support China’s allegations.
The detentions, which include Stern Hu, Rio’s chief iron ore negotiator, have complicated annual negotiations to set the price at which mills import contracted iron ore. The men were detained on 5 July.
This year’s negotiations have been more fraught than usual, because they coincided with the collapse of a deal by Chinese flagship aluminium firm, Chinalco, to increase its stake in Rio.
Instead, Rio and BHP plan to merge their iron ore operations in western Australia, although they say they will keep marketing separate.
The Chinese fear the tie-up between the two Anglo-Australian giants will allow them to keep prices high. The Chinese are currently seeking bigger price cuts than their Korean and Japanese counterparts.
The future of Hu and his colleagues is uncertain.
Under Chinese law, detainees may be held for some time without being charged, and interrogated without access to legal counsel. Once charged and formally arrested, the judicial process then begins.
Australian Prime Minister Kevin Rudd warned China it has significant economic interests at stake in detaining an Australian mining executive on spying charges, adding that the world was watching the case.
China’s longstanding ties with Australia have been damaged by the case. America has also weighed in on the case, as US commerce secretary Gary Locke, who is visiting Beijing this week, called for the Chinese government to show more transparency over the arrests.