FILE PHOTO: Artisanal miners work at Tilwizembe, a former industrial copper-cobalt mine, outside of Kolwezi, capital city of Lualaba Province in the south of the Democratic Republic of the Congo, June 11, 2016. REUTERS/Kenny Katombe
FILE PHOTO: Artisanal miners work at Tilwizembe, a former industrial copper-cobalt mine, outside of Kolwezi, capital city of Lualaba Province in the south of the Democratic Republic of the Congo, June 11, 2016. REUTERS/Kenny Katombe