Why don't miners get boiled to death at $4$ km deep?
The Wikipedia page for the Mponeng gold mine makes the maximum rock temperature at 66 °C, and if all you read from the Wikipedia page on the geothermal gradient is the stuff in bold, ... The map below shows the location of the mine with respect to the Kaapvaal Craton: The mine is located at the white dot. As you can see it is …
