In South Africa's coal heartland, gray smog hangs over parts of the Mpumalanga province like a thick blanket, while miners descend underground to chip away at the black rock.

One of them is Mooi Masuku, an artisanal coal miner of 17 years, who says a new bill to legalize informal mining is key to protecting and creating jobs, particularly as critical minerals are eyed for green technologies.

"In South Africa, I think the government will begin to see why it should legalize (artisanal mining) to protect these jobs," said Masuku, sitting on a concrete slab outside his home in the Nomzamo informal settlement in the town of Ermelo.