FILE PHOTO: Excavators and drillers at work in an open pit at Tenke Fungurume, a copper and cobalt mine northwest of Lubumbashi in Congo's copper-producing south

FILE PHOTO: Excavators and drillers at work in an open pit at Tenke Fungurume, a copper and cobalt mine northwest of Lubumbashi in Congo’s copper-producing south

Excavators and drillers work in an open pit at Tenke Fungurume, a copper and cobalt mine in the Democratic Republic of Congo. BMW hopes to use blockchain to source ethical cobalt. Photo: Reuters / Jonny Hogg

March 9, 2018 6:24 PM (UTC+8)