Rio Tinto is experiencing iron ore mine operational problems, particularly in the Greater Brockman hub in the Pilbara, leading the miner to cut its shipments forecast from the area for 2019.
Rio Tinto says the challenges are from a higher proportion of certain lower grade products, partly to protect the quality of its flagship Pilbara Blend.
The global miner cut its forecast for 2019 Pilbara shipments on a 100 per cent to between 320 million tonnes and 330 million tonnes, from between 333 million tonnes and 343 million tonnes.
Rio Tinto's ASX-listed shares were down 4.3 per cent to $101.16 at 1300 AEST on Thursday - a day after hitting a record high of $106.85 and having risen from $78 at the start of the calendar year.
Its London-listed shares fell 4.7 per cent overnight following the Pilbara announcement.
