Antonio Costa resigned on Tuesday, hours after prosecutors detained five people, including his chief of staff, and named two formal suspects close to him in an investigation into lithium mining and hydrogen projects.
With more than 60,000 metric tons of known lithium reserves, Portugal is Europe’s biggest lithium producer, but its miners sell almost exclusively to the ceramics industry.
They are now preparing to produce the higher-grade lithium used in electric cars and electronic appliances, as Europe seeks to develop its own strategic energy resources to reduce dependence on suppliers like China.
Environment agency APA earlier this year gave environmental approvals for local company Lusorecursos to extract battery-grade lithium and for London-based Savannah Resources to develop four open-pit mines.