China, the leading holder of international deep sea exploration licences, increases its lead in the race for alternative sources of battery minerals by taking samples from cobalt-bearing mountains deep in the Pacific.
Cavalcanti joins Samarco as it attempts to renegotiate billions of dollars in debt with creditors and restart operations after a tailing dam burst in 2015, killing 19 people.
China is the world's biggest consumer of the metal but its own copper mine production has been stagnating amid a broad crackdown on pollution, exacerbating a heavy reliance on imports.