Brazil’s Vale, the world’s second-largest mining company, is losing $2 to $3 a tonne in iron ore shipping costs because of China’s port ban on its giant Valemax ships, Jose Carlos Martins, Vale’s iron ore chief, said on Thursday.

The 400,000 deadweight tonne Valemax ships, designed for the China trade, should save the company $6 per tonne compared with smaller ships, Martins told investors and analysts.

The additional costs come because Vale must transfer Brazilian ore from the Valemaxes at sea in Asia to smaller vessels for the final journey to China, Martins said.