PERTH - A Rio Tinto iron-ore freight train was derailed in western Australia's Pilbara region on Thursday, halting the supply of ore from most of its mines to port, the company said on Friday.

Between 50 and 60 ore cars in a train of about 230 fully-loaded cars derailed late on Thursday about 80 km north of the outback mining town of Tom Price, said Rio Tinto spokesperson Gervase Greene.

Rio said it was too early to say how long it would take before operations resumed on the main line, but added that the clean up was expected to take several days.

"At this moment, all loading at the port is continuing as per normal. Shipments are not expected to be affected at this point but it all depends on how long the blockage is," Greene said, adding that the port had healthy stockpiles of iron ore.

A typical train is about a mile long and consists of 300 cars hauling 24 000 metric tons of ore. The trains travel hundreds of miles from Pilbara mines to west coast ports to waiting freighters.

Rio said nobody was injured in the incident. Unions told Australia's ABC state radio that it could take five days to clear the line.

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