Mponeng is a

gold mine Gold Mine may refer to: *Gold Mine (board game) *Gold Mine (Long Beach), an arena *"Gold Mine", a song by Joyner Lucas from the 2020 album '' ADHD'' See also * ''Gold'' (1974 film), based on the novel ''Gold Mine'' by Wilbur Smith *Gold mining ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

Gauteng Gauteng ( ) is one of the nine provinces of South Africa. The name in Sotho-Tswana languages means 'place of gold'. Situated on the Highveld, Gauteng is the smallest province by land area in South Africa. Although Gauteng accounts for only ...

province. Previously known as Western Deep Levels #1 Shaft, the underground and surface works were commissioned in 1987. It extends over below the surface,. and is considered to be one of the most substantial gold mines in the world. It is also currently the world's deepest mine from ground level, reaching a depth of 4 km (2.5 mi) below ground level. The trip from the surface to the bottom of the mine takes over an hour. Over 5400 metric tonnes of rock are excavated from Mponeng each day. At a price of $19.4 per gram of gold, the mine only needs to extract 10 grams of gold per ton excavated to remain profitable. The mine contains at least two

gold reef In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation. The hydraulic flow involved ...

s, with the deepest one metre thick. Harmony Gold purchased Mponeng from

AngloGold Ashanti AngloGold Ashanti Limited is a global gold mining company. It was formed in 2004 by the merger of AngloGold and the Ashanti Goldfields Corporation. It is now a global gold producer with 21 operations on four continents. The company is listed ...

in September 2020. Along with AGA's Mine Waste Solutions, Harmony paid approximately $300m.

Physical conditions

The temperature of the rock reaches , and the mine pumps

slurry ice Slurry ice is a phase changing refrigerant made up of millions of ice "micro-crystals" (typically 0.1 to 1 mm in diameter) formed and suspended within a solution of water and a freezing point depressant. Some compounds used in the field are sa ...

underground to cool the tunnel air to below . A mixture of concrete, water, and rock is packed into excavated areas, which further acts as an insulator. Tunnel walls are secured by flexible

shotcrete Shotcrete, gunite (), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique, first used in 1907 invented by Carl Akeley. It is typically r ...

reinforced with steel fibers, which is further held in place by diamond-mesh netting. In 2008, researchers looking for

extremophile An extremophile (from Latin ' meaning "extreme" and Greek ' () meaning "love") is an organism that is able to live (or in some cases thrive) in extreme environments, i.e. environments that make survival challenging such as due to extreme temper ...

organisms discovered the bacterium ''

Desulforudis audaxviator "''Candidatus'' Desulforudis audaxviator" is a monospecific genus of bacteria that lives in groundwater at depths from below the Earth's surface. Etymology The name comes from a quotation from Jules Verne's novel ''Journey to the Center of th ...

'' present within groundwater samples from kilometers deep in the mine.

In popular culture

Danny Forster Daniel Keith Forster (born September 19, 1977) is an American designer, television host, film and television producer, director, professor, and speaker. He is best known as the host of the Science Channel series ''Build It Bigger''; as the crea ...

visited the mine for the fifth episode of ''

Build It Bigger ''Extreme Engineering'' is a documentary television series that aired on the Discovery Channel and the Science Channel. The program featured futuristic and ongoing engineering projects. After ending of season 3 it airs under the ''Build It Bi ...

s eighth season. Millan Ludeña, an Ecuadorian marathon runner, became the first person to run a half-marathon fully underground in the deepest part of Mponeng Gold Mine. A Guinness World Records adjudicator was on hand to document the race and issued the certificate for the deepest half-marathon.

References

{{reflist Gold mines in South Africa Economy of Gauteng