In the 1970s, South Africa was the world's most prolific exporter of gold. Over the years, industrial decline has seen widespread closures of the mines across the country. However, Johannesburg sits on the biggest gold basin ever discovered. It's perhaps not surprising that many of these abandoned mines have seen a recent boom in illegal mining activity. Every day, hundreds of illegal gold miners—known as Zama Zamas—descend deep beneath the surface. The miners often spend weeks underground, toiling away at the country's untapped gold reserves. Observers have suggested that illegal mining is now so widespread, black-market gold arguably supports the communities once subsistent on the same mines they worked in before they shut down. The lack of policing in the mines has seen the practice go on largely unabated—the extensive network has become an arena to deadly gang warfare between rival factions. VICE News visited illegal mines near Johannesburg to meet the Zama Zamas risking life and limb every day in the violent struggle for South Africa's illegal gold.