Unfavourable weather conditions caused by the tropical cyclones Dianne and Carlos have forced Rio Tinto to suspend its coastal operations in the Pilbara region of Western Australia.

The cyclones may also affect the tonnage dispatched for the first quarter of 2011.

Though all the mines have been operational since 14 February 2011, despite the weather conditions, a single track of 35km south of Dampier was been damaged by derailment of a loaded train and cannot be mended until later this week.

Cyclone Carlos led to the suspension of operations near Port Walcott, which carries all the products of Robe Valley and Yandicoogina.

Rio Tinto iron ore plans to assess the impact of weather conditions on the stock levels and shipping schedules to try to ensure normal operations at the earliest.