In a securities filing, Vale said that if the alternatives were not effective, 2020 iron ore production, most recently forecast at between 340 million tonnes and 355 million tonnes, may be impacted.

In February, Vale had reduced iron ore output estimates for the first quarter by 63 million to 68 million tonnes given problems at the Brucutu mine, its largest in Minas Gerais state.

Operations at Brucutu, with an annual capacity of 30 million tonnes, have been halted at various times over the past year amid growing pressure on the company to reduce the risk of another accident following the fatal collapse of its tailings dam at Brumadinho last January.