An investigation has found children as young as four working in cobalt mines in Africa.
The mineral is an essential part of batteries used for smartphones and laptops, the sales of which earn billions for multinational companies.
Sky News has discovered many of those extracting it are earning as little as 8p a day in desperately dangerous conditions.
Dorsen, aged just eight years old, speaking to an interviewer in the rain and through a translator, said: "When I'm working here, I am suffering.
"My mother - she's already dead, and I have to work all day, and my heads hurts me."