A train with no-one on board travelled at 100km/h for 92km in a remote area of Australia before being deliberately derailed.
The train was travelling at an average speed of 110 kilometres per hour before the derailment at Turner, 120 kilometres south of Port Headland.
BHP Billiton said it had suspended all its iron ore rail operations in Western Australia on Monday after the incident.
The train was traveling on BHP's rail line from Newman to Port Hedland in the Pilbara region of Western Australia.
"We have a long-term contract with BHP and we haven't received a notification so far", said an official at the mill in southern China who declined to be named as he was not authorised to speak to media.
While the driver was outside of the locomotive, the train started off down the track.
BHP said in a statement on Wednesday that its reserves of the steelmaking ingredient at the Port Hedland hub were not expected to cover the entire period of disruption following the incident, and that it would be liaising with its customers about its contractual commitments over that time.
The Australian Transport Safety Bureau said damage to the train was substantial and it is estimated about 1.5km of track was damaged.
Industry specialists were confused about why the train would have run away down the tracks.
The mining company also told The West Australian it is working with authorirites to investigate the situation.
BHP confirms the suspension of normal train operations but all of its main mines remain operational. "We can not speculate on the outcome of the investigation", BHP said.
BHP said that more than 130 people were...
BHP will be questioned by the transport safety regulator.