The world’s fourth-biggest iron-ore producer reported a rise in second-quarter iron-ore shipments and said first-half exports of the steel ingredient were the highest in its history.

Shares in Australia’s top three iron ore miners have fallen since US President Donald Trump threatened to impose 10 per cent tariffs on China.

The uptick in iron ore shipments comes as Fortescue, the world’s fourth largest iron ore miner, is making continuous efforts to boost output at its new high grade Iron Bridge project, which is expected to be producing at full capacity later this year.

The mining giant posted a sharp rise in second-quarter copper production thanks to a jump in output at Escondida, the world’s largest copper mine.

Fortescue Ltd.’s second-quarter iron ore shipments edged up 1% from the year before, amid rising concern the world’s biggest producers of the steel-making material will create a supply glut as demand from China wanes.