Rio Tinto could make another billion-dollar investment decision on a new Australian iron ore mine in the coming year, as completion of the $US3.1 billion ($4.5 billion) Gudai-Darri mine soothes its operational struggles and turns the focus onto the next wave of investment.

Rio’s iron ore boss Simon Trott said the start of production at Gudai-Darri was a “turning point” for a business that had recently struggled with old mines, declining product quality and multiple downgrades to export volumes.