Four Shanghai-based employees of Anglo-Australian miner Rio Tinto have been detained without explanation by authorities as the company continues to grapple with Chinese iron ore buyers over iron ore prices, the Financial Times reported. The four workers are reportedly part of the firm’s iron ore sales team, and were held for questioning on Sunday. One is said to be an Australian passport holder and the others are reportedly Chinese nationals. Rio Tinto said it was “concerned about the employees’ wellbeing” and “has sought clarification on what has occurred.” Chinese iron ore buyers recently rejected Rio’s proposed 33% price reduction for iron ore contracts for 2009-2010, though South Korean and Japanese buyers signed contracts. Chinese buyers are holding out for steeper price cuts. Rio has also been criticized in China for withdrawing from a proposed US$19.5 billion investment by Aluminum Corp of China.