Depth below surface4,000 m
21,053Toothbrushes
4.5 tenthsMount Everest heights
Placeholder image
Deepest Mine
Mponeng Gold Mine reaches 4 km below the surface, where rock temperature hits 66 C/Collective & Conceptual
The Mponeng Gold Mine near Johannesburg, South Africa, is the deepest mine in the world, reaching a depth of approximately 4,000 meters below the surface. At that depth, the natural rock temperature reaches 66 C (151 F) due to the geothermal gradient, requiring massive refrigeration systems that pump ice slurry underground to cool the working areas to a tolerable 28 C. The pressure at the deepest levels is about 100 times atmospheric pressure. Miners descend in a series of elevators over a journey of about an hour. The mine produces roughly 5,400 kg of gold per year from ore that yields just 8 grams of gold per tonne of rock. About 5,000 miners work at Mponeng, making it a small underground city.
Measurements
Rock temperature at depth339 K
10 tenthsSun-baked car interior
21.6 millionthsSun cores
1.03Clothes dryer temps
About 66 C
Cooled working temperature301 K
8.1 tenthsRunning car engines
1.05Wine cellars
8.4 tenthsSaunas
About 28 C
Rock pressure at depth10 million Pa
2.5 tenthsDeep sea pressures
9.2 hundredthsMariana Trench depths
55.6Tennis ball pressures
About 100 atm
Gold produced per year5,400 kg
5.4 quintillionBacteria
10.8 millionHummingbird eggs
108 trillionYeast cells
Descent time3,600 s
16.3 millionthsDog years
1.6 millionthsHuman lifespans
3.6 trillionCPU clock cycles
About 1 hour