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Mponeng is a gold mine in South Africa's North West Province. It extends over 3.8 kilometres below the surface,[1] and is considered to be one of the deepest and most substantial gold mines in the world.[2] The trip from the surface to the bottom of the mine takes over an hour.[1]

Over 5400 metric tonnes of rock are excavated from Mponeng each day.[1] At a cost of $19.4 per gram of gold extracted, the mine needs to recover only 10 grams of gold per ton excavated to remain profitable.[1] The mine contains at least two gold reefs, with the deepest one metre thick.[1]

The temperature of the rock reaches 66 °C (151 °F), and the mine pumps slurry ice underground to cool the tunnel air below 30 °C (86 °F).[1] A mixture of concrete, water, and rock is packed into excavated areas, which further acts as an insulator.[1] Tunnel walls are secured by flexible shotcrete reinforced with steel fibers, which is further held in place by diamond-mesh netting.[1]

The endemic bacterium Desulforudis audaxviator was discovered within groundwater samples.

Danny Forster visited this mine to do an episode of Build It Bigger for season number three.


  1. ^ a b c d e f g h Wadhams, Nick (March 2011), "Gold Standards: How miners dig for riches in a 2-mile-deep furnace", Wired 19 (3): 42 .
  2. ^ "Mponeng, South Africa". Mining Technology. Retrieved 9 May 2011. 

Coordinates: 26°26′10″S 27°25′50″E / 26.43611°S 27.43056°E / -26.43611; 27.43056