The TauTona Mine or Western Deep No.3 Shaft,[1] is a gold mine in South Africa. At approximately 3.9 kilometers (2.4 mi) deep,The mine is so deep that temperatures in the mine can rise to life-threatening levels. Air-conditioning equipment is used to cool the mine from 55 °C (131 °F) down to a more tolerable 28 °C (82 °F). The rock face temperature reaches 60 °C (140 °F). https://en.wikipedia.org/wiki/TauTona_Mine