The deepest mine in the world is the Mponeng gold mine in South Africa, which reaches about 4 km (2.5 mi) below the surface, followed by its neighbour TauTona at about 3.9 km and the closed Savuka mine at about 3.7 km, according to the List of deepest mines on Wikipedia (2026), which ranks mines by the vertical distance from the mine entrance to the deepest excavated point. Seven of the ten deepest are South African gold mines on the Witwatersrand. Change the yardstick to depth below sea level, though, and the record passes to the Kidd Mine in Ontario, Canada, at 2,733 m below sea level. So the measuring rules come first, then the ranking.
Depth Below the Entrance, Below Sea Level, or Down a Borehole
The standard ranking measures depth below surface: the difference in elevation between the mine’s entrance, usually the top of its main shaft, and the lowest point anyone has dug. The list used here only includes mines at least 2,224 m deep, the depth of Krubera Cave in the western Caucasus, which it treats as the deepest known natural cave (our guide to the deepest caves in the world covers the rivals for that title). It also limits itself to excavations made to extract resources that people can physically enter.
That definition produces the order in the table below. Three other yardsticks give different answers.
- Current working depth versus deepest ever reached. Mponeng is listed at 4.0 km, and the mine is described as reaching more than 4 km, yet its own Wikipedia article also gives current working depths of roughly 3.8 km, and expects it to go beyond 4.2 km in the mine’s remaining life. Published depths for the same mine move as levels are opened, closed and flooded.
- Depth below sea level. The Witwatersrand ridge around Johannesburg stands 1,700 to 1,800 m above sea level, so South Africa’s mines start very high. The Kidd Mine near Timmins starts much lower, and its 3,014 m below surface takes it to 2,733 m below sea level, the deepest of any mine by that measure.
- Open pits and boreholes. Open-pit mines are far shallower: Bingham Canyon in Utah, the deepest open pit in the world, is about 1.2 km deep. Boreholes go much further but nobody can enter them. The Soviet Kola Superdeep Borehole reached 12,262 m in 1989 and remains the deepest human-made hole, but it is a scientific drill hole, not a mine.
The 10 Deepest Mines, from Mponeng to Kolar
| Rank | Mine | Country | Depth | Resource | Status |
|---|---|---|---|---|---|
| 1 | Mponeng | South Africa | 4.0 km | Gold | Active |
| 2 | TauTona | South Africa | 3.9 km | Gold | Active (part of Mponeng) |
| 3 | Savuka | South Africa | 3.7 km | Gold | Closed |
| 4 | East Rand (ERPM) | South Africa | 3,585 m | Gold | Closed 2008 |
| 5 | Driefontein | South Africa | 3,420 m | Gold | Active |
| 6 | Kusasalethu | South Africa | 3,388 m | Gold | Active |
| 7 | Empire Mine | United States | 3,355 m | Gold | Closed 1956 |
| 8 | Kloof (KDC) | South Africa | 3,347 m | Gold, uranium | Active |
| 9 | LaRonde | Canada | 3,260 m | Gold, copper, silver, zinc | Active |
| 10 | Kolar Gold Fields | India | 3,217 m | Gold | Closed 2001 |
The Witwatersrand: Why South Africa Holds Seven Places
The answer lies in the rock. The gold-bearing strata of the Witwatersrand Supergroup come to the surface around Johannesburg, where their discovery set off the gold rush of 1886 that founded the city, and then dip south at about 30°, disappearing beneath younger rocks. Following a reef that dips that steeply means chasing it ever deeper, and in places mining now works these buried layers 4 km down. A meteor impact near Vredefort about 2.02 billion years ago helped preserve the basin by lowering it inside the crater. The Witwatersrand Basin holds the world’s largest known gold reserves and has yielded over 40,000 tonnes since 1886, about 22% of all the gold accounted for above ground, so the reward for going deeper has been big enough to pay for it.
The top three are one complex near Carletonville, west of Johannesburg, all once part of Western Deep Levels and connected underground on several levels. TauTona, formerly Western Deep Levels No. 3 Shaft, was built by the Anglo American Corporation: shaft sinking started in 1956, the 2 km main shaft was commissioned in 1961 and ore production began in 1962. Its name means “great lion” in Setswana. Mponeng, the former No. 1 Shaft, began mining in 1986 and took its present name in 1999. Harmony Gold bought all three from AngloGold Ashanti in 2020; TauTona closed in 2018 but reopened in 2020 as part of Mponeng, while Savuka went onto care and maintenance in 2017 and closed in 2024.
The other South African entries spread along the same goldfield. East Rand Proprietary Mines at Boksburg, east of Johannesburg, was the deepest mine in the world until 2008 at 3,585 m, when TauTona overtook it after a deepening project; it closed the same year. Driefontein, Kusasalethu and Kloof sit on the West Wits field, discovered in 1931, where Kusasalethu was developing new workings between 3,000 and 3,600 m.
Heat, Rockbursts and Ice at Mponeng
Four kilometres down, the rock at Mponeng reaches about 66 °C. The mine pumps slurry ice underground to bring the air in the tunnels below 30 °C, and backfills mined-out spaces with a mix of concrete, water and rock that helps insulate them. A trip from the surface to the deepest point takes more than an hour, and over 5,400 tonnes of rock are hoisted every day; in 2023 the mine produced 7,449 kg of gold. Heat is not the only hazard. Removing that much rock shifts the stresses in a faulted basin, and vertical stress at these depths can reach 80 to 100 MPa. A magnitude 2 tremor in March 2020 killed three miners. The depth also brought a scientific find: in 2008 researchers identified the bacterium Desulforudis audaxviator in groundwater kilometres down, named from a line in Jules Verne’s Journey to the Centre of the Earth.
Empire, LaRonde and Kolar: the Deep Mines Outside South Africa
Only three countries besides South Africa make the top 10. The Empire Mine at Grass Valley, California, is seventh at 3,355 m, even though it closed in 1956. Between 1850 and its closure it produced 5.8 million ounces of gold from 367 miles (591 km) of underground passages, helped by hard-rock miners from Cornwall and by the steam-driven Cornish engine that pumped out the water seeping into its depths. It has been run by California State Parks as a historic site since 1975, a survivor of the boom traced in our California Gold Rush geography piece.
LaRonde, ninth at 3,260 m, is a gold mine in Quebec’s Abitibi-Témiscamingue region, 62 km west of Val-d’Or, which began commercial operation in 1988. Its Penna shaft is believed to be the deepest single-lift shaft in the Western Hemisphere, descending more than 3 km, and the mine is expected to keep operating until 2032. Kolar Gold Fields in Karnataka, India, tenth at 3,217 m, closed on 28 February 2001 when gold prices fell, even though gold remained. One of India’s first power stations was built there in 1889 to run the mines, and the deep workings later hosted particle physics experiments from the 1960s until 1992.
Kidd Mine, Homestake and the Next Tier Down
The Kidd Mine at Timmins, Ontario, sits 13th on the below-surface list at 3,014 m, but it holds two records of its own: the deepest copper-zinc mine and the deepest mine below sea level. An airborne survey by Texas Gulf Sulphur picked out the deposit in 1959, ore production began in 1966 as an open pit, and the mine is now owned by Glencore. Its ore is made into concentrate at the Kidd Metallurgical Site, 27 km southeast of the mine, which also smelted and refined it until 2010; since most of that plant closed, the concentrate has been shipped to Quebec for processing.
Between Kolar and Kidd sit Blyvooruitzicht (3,213 m) and Moab Khotsong (3,052 m), both South African gold and uranium mines. Just behind Kidd come Morro Velho in Brazil at about 3.0 km, South Africa’s South Deep and Target 1, and the Lucky Friday silver, lead and zinc mine in Idaho at 2,922 m. Of the 24 mines on the full list, 16 are in South Africa, three each are in Canada and the United States, and one each is in India and Brazil. Almost all of them mine gold; the exceptions are base-metal mines such as Kidd, Lucky Friday and the Creighton nickel mine at Sudbury, Ontario, 2.39 km deep.
Further down the list, the Homestake Mine in Lead, South Dakota, reached 2,438 m before it closed in 2002, then the largest and deepest gold mine in the Western Hemisphere. In the 1960s Raymond Davis Jr. used its depths to detect solar neutrinos, and since 2011 it has been the Sanford Underground Research Facility. Like Kolar and Mponeng, it shows that the deepest mines end up studied for physics and biology as well as for ore. Where else gold is dug, and why the deposits cluster where they do, is mapped out in our gold mining geography overview.