Rio Tinto has warned its iron ore operations at Pilbara, Western Australia continue to be hampered by Tropical Cyclones Dianne and Carlos and this will affect shipped tonnage for the first quarter of this year. 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. Rio says it has kept all 14 mines working, though Dampier and Port Walcott (Cape Lambert) operations have continued intermittently since 14 February 2011, with frequent interruptions from the excessive rainfall, swells and winds. A train derailment has also prevented trains from entering Dampier, and is not expected to be fully repaired until later this week.