Already reeling from a deadly dam disaster in Brazil that has forced Vale, the world’s biggest producer, to curb output, another 14m tonnes of supply is at risk after the US took fresh action against Iran. “Iran exported almost 14m tonnes of iron ore in 2018, accounting for 1 per cent of total seaborne iron ore supply for the year. Now, Iranian iron ore exports are likely to approach zero for as long as these sanctions last,” said analysts at Jefferies.