The mining company said no workers were in the vicinity, but the union says five staff were working further down the line.It is understood work to clear the train line has started and authorities have launched an investigation.
Iron ore trains can be several kilometres long and Mr Busson confirmed the group were unharmed, but said they were shaken by the incident.He said if workers were closer to the site of the crash the consequences could have been far more serious. "The recovery train is reported to have collided with the ore train it was sent to recover after it was disabled by a mechanical failure," a spokesman said in a statement.The spokesman said in its early stages the investigation would focus on the operation of and adherence to signalling systems in the area.
"On this occasion it did work. It was a welcome back-up, but you can't rely on that all the time," he said.It is the second Rio Tinto derailment in the Pilbara this year and the third in the past 12 months.