Australia's third largest mining firm Rio Tinto has announced that production at its coastal operations in the Pilbara region continue to be hampered by ongoing weather issues associated with Tropical Cyclones (TC) Dianne and Carlos, that are likely to impact on shipped tonnage for the first quarter of this year.

TC Carlos is currently 100 kilometres north-west of Broome, moving in a west-southwest direction at a speed of 20 kilometres per hour. It is expected to impact the Pilbara coast from early Tuesday morning, bringing heavy rain and strong winds.

Despite ongoing challenges, operations have been maintained at all 14 mines across the region. Dampier and Port Walcott (Cape Lambert) operations have continued intermittently since 14 February 2011, with frequent interruptions from the excessive rainfall, swells and winds. The reformed TC Carlos required the tie-down of all port operations from later today.

Rio Tinto said in a statement that conditions led to a partial derailment late on 17 February, when a loaded train damaged a single-line section of track 35 kilometres south of Dampier. This has prevented trains from entering Dampier, and is not expected to be fully repaired until later this week.

Train movements to Port Walcott (carrying all Robe Valley and Yandicoogina products) have remained unaffected from the derailment, but are now also suspended as part of the tie-down in advance of TC Carlos.

Rio Tinto iron ore will review the impact on stock levels and shipping schedules as a result of the conditions. As is normal practice, where appropriate, scheduled maintenance projects have been brought forward to facilitate a quick return to normal rail and shipping operations when conditions allow.