The disaster killed 270 people but the court action only benefits the families of 131 workers directly hired by Vale.

The US company is introducing a way of extracting more of the lithium that’s normally captured in salts, thereby lifting yields to 80-85% from 50-55%.

Daniel Jadue, the current front-runner in polls for November’s elections in Chile, wants to align mining rules with Peru, Argentina and Bolivia so they don’t compete for investments.

Engineers and technicians told the auditors that the tailings at Xingu had not been properly drained.

The resource is "strategically important" because it requires smaller evaporation ponds to put the project into production, the company says.

Shipments from Rio Tinto were seen declining, while Vale has interrupted production at two mines over safety concerns, reducing its output by 40,000 tonnes a day.

There are signs that Peru’s likely next president will be less of an enemy to mining than first feared.