The man stopped digging in his yard. Instead, he cut through the floor of his house, which he was renting, and dug to about thirty feet, carting out ore at night. Zanga Muteba, a baker who then lived in Kasulo, told me, “All of us, at that time, we knew nothing.” But one evening he and some neighbors heard telltale clanging noises coming from the man’s house. Rushing inside, they discovered that the man had carved out a series of underground galleries, following the vein of cobalt as it meandered under his neighbors’ houses. When the man’s landlord got wind of these modifications, they had an argument, and the man fled. “He had already made a lot of money,” Muteba told me. Judging from the amount of ore the man had dug out, he had probably made more than ten thousand dollars—in Congo, a small fortune. According to the World Bank, in 2018 three-quarters of the country’s population lived on less than two dollars a day.