Rio Tinto’s flagship iron ore division has delivered its best export volumes in five years, but the company’s fragile ceasefire with the Mongolian government appears to be on shaky ground after a new tax grab related to its giant copper mine.

Rio shipped 331.8 million tonnes of iron ore from Western Australia in 2023, as the ramp-up of the new Gudai Darri mine enabled the miner to post its second-biggest, annual export result.