Over two-and-a-half miles below the surface, the deepest gold mine ever is getting deeper by the day and earthquakes are a constant threat. Danny Foster takes viewers behind the scenes of the most dangerous construction project in the world with a new season of Extreme Engineering, premiering 6 July at 22:00 on Discovery Channel (DStv channel 121).

Just an hour outside of Johannesburg, the AngloGold Ashanti Mponeng Mine is already the deepest mine on earth, where 5 700 of the world’s toughest workers face temperatures hotter than 150 degrees every day. A subterranean gold factory two-and-a-half miles deep, the mine boasts more tunnels than the New York City subway, as well as the world’s longest elevators.

Most of the original gold deposit has already been mined and the rest will be gone in just eight years. But now geologists have found more gold, over three miles beneath the surface, in a reef that holds more that 140 tons of the precious metal, worth six billion dollars.

According to Randel Rademann, General Manager of AngloGold Ashanti Mponeng Mine, the project will give the mine the potential opportunity to extend its life until 2029. In addition, the deepening crew has just 700 feet to go before they reach the six billion dollar deposit that will keep South Africa’s most important mine producing gold for decades to come.

Watch as Danny joins the team who works in the world’s deepest gold mine and, in doing so, sets world records every day.

In this series of Extreme Engineering, Danny also travels to Singapore; Kuwait City; and New Orleans, where the world’s strongest hurricane protection system is being built. Watch as he works with the designers; engineers; and builders responsible for these enormous designs.