Mponeng is an ultra-deep tabular gold mine in South Africa in the Witwatersrand Basin of the Gauteng Province.

[8] As part of the Witwatersrand, the largest gold mineralization on earth, Mponeng is the result of the discovery of the basin by Europeans.

Harmony Gold also acquired Mine Waste Solutions as they gathered the remainder of AGA's assets in late 2020.

[21] Tunnel walls are secured by flexible shotcrete reinforced with steel fibers, which is further held in place by diamond-mesh netting.

[21] In 2008, researchers looking for extremophile organisms discovered the bacterium Desulforudis audaxviator present within groundwater samples from kilometers deep in the mine.

[22] The name 'Audaxviator' comes from a Latin-language passage in the novel Journey to the Centre of the Earth by Jules Verne: "Descende, audax viator, et terrestre centrum attinges."

[24] In the Mponeng mine the Ventersdorp Contact Reef is mainly interbedded quartzite and coarse conglomerates and constitutes only a meter or two of thickness.

[citation needed] A large portion of this occurs in the Witwatersrand Basin, home to over 270 tailings storage facilities, covering 18,000 Ha.

[32] Tailings result from the crushing and grinding process of the ore, very fine silt sized material is produced and collected in mounds.

Gold mining operations contribute to greenhouse gas emissions primarily through the use of heavy machinery, ore processing, and energy-intensive refining methods.

Diesel-powered equipment, explosives, and electricity consumption—largely derived from fossil fuels in South Africa—lead to significant carbon dioxide (CO₂) and methane (CH₄) emissions.

[35][36] A study in 2020 found elevated value of silica and uranium in PM10 airborne pollution from TSFs of gold mines in the area.

The caveats of prevention and remediation are the fact that both of which are extremely difficult and expensive, neither the mining industry or South Africa could afford a completely turn around on pollution.

[31] Other than prevention and remediation, it has been proposed that in order to protect environments remaining tailings materials should be removed from TSFs if containment is not secure.

[37] Seismicity in mines is common as removing mass amounts of rock can change stress dynamics, especially if pre-existing faults exist.

[38][39] On December 27, 2007 a dyke within Mponeng experienced a 1.9 magnitude event caused by stress change due to excavation within the mine.

[47] A prominent use of deep mines and their associated, often low magnitude, earthquakes is to connect laboratory scale experiments to real world situations.