More than 20,000 miners are illegally prospecting on the reservation and polluting rivers with mercury used to separate gold from ore.

It would take around 60 days for Vale to implement the solution, according to a person familiar with the plan.

A study conducted in Peru shows that, if not properly conducted, formalization processes may be detrimental to the environment.

The deal will ease concerns over a potential stoppage that would have further tightened global supplies of the metal.

Top lithium producer also said it would sell $630m of shares to fund expansion overseas.

The collapse of a dam at the Samarco mine complex in 2015 killed 19 people and severely polluted the Doce River with mining waste.

Socialist Pedro Castillo was closing in on victory in Peru's presidential election on Thursday, holding a slim lead of some 63,000 votes over conservative rival Keiko Fujimori.