Major said 500,000 people were working in gold mines in 1990, with the official number now 150,000. Some of those who lost their jobs are certainly doing illegal gold mining, he said.
Buyers often come to the ad hoc operations to weigh and purchase gold. Miners say they also sometimes sell gold within their squatter camps. Mthembu said he melts all his gold particles together and sells it at the end of the week.
Zingaphi Jakuja, spokeswoman for the South African Department of Mineral Resources, said the ministry is collaborating with law enforcement agencies to combat illegal mining "as the activities are generally fuelled by complex criminal activities."
Illegal miners are generally undeterred by the threat of arrest.
"When the police come, we run away. We've never gotten caught and we don't want to give them a reason to catch us," said 45-year-old Daniel Mazibuko who has three children and a wife. "It's illegal, but I still do it because I'm suffering and if there's no food at home I must do this job."
"Sometimes I make 100 to 150 rand ($11-$17) per day if I'm lucky. In my best week I've made 500 rand ($57)," he said.
On a recent day he was working with 21-year-old Siphelele Dyasi, who smoked a cigarette as he poured heavy buckets of water into a yellow plastic bin and shook it to separate the soil. The miners sometimes endanger their health by using mercury to extract the gold.
"There's no other choice, you go into it knowing the risks," said Dyasi, who came to Johannesburg from the distant Eastern Cape of South Africa after his father died and his mother couldn't provide for him and his brothers and sisters.
Dyasi and Mazibuko were trying their luck outside the Tudor Shaft mine, not far from the Durban Deep mine. At least five makeshift mining chutes could be seen among dusty fields of rock, orange dirt and black rocks near pools of water, that the miners use and recycle in their prospecting.