AngloGold Ashanti’s Mponeng gold mine, located south-west of Johannesburg in South Africa, is currently the deepest mine in the world. The operating depth at Mponeng mine ranged from between 3.16km to 3.84km below the surface by the end of 2018. Ongoing expansions are expected to extend the operating depth further to 4.27km.
The ore reserves left at Mponeng reached 46.18 million ounces (Moz) by December 2018. The mine produced 265,000oz of gold in 2018.
Mponeng extracts the Ventersdorp Contact Reef (VCR) of the West Wits region of South Africa. The deep underground mine employs a sequential grid mining method. The shaft-sinking process at Mponeng began in 1981 while gold plant complex and the shafts were commissioned in 1986.
The mine is undergoing a two-phase expansion, which will extend its mine life upon completion. The first phase is expected to be completed by 2019 while the second phase has been temporarily put on hold due to capital constraints. AngloGold, meanwhile, announced plans to divest its South African assets, including the Mponeng gold mine in May 2019. The divestment will allow the company to appropriately allocate capital and resources to more attractive and higher return-generating projects in its portfolio.
The Driefontein mine, owned by Sibanye-Stillwater, is located near Carletonville in the Gauteng Province of South Africa. The mine lies within the West Wits Line Goldfield of the Witwatersrand Basin. It is currently the second deepest mine in the world with its depth extended up to 3.42km.
The Driefontein mine operation could be traced back to 1952. The mine consists of six producing shaft systems extracting ore from three reefs, namely the VCR, the Carbon Leader Reef (CLR), and the Middelvlei Reef. Driefontein uses a combination of longwall and scattered mining methods.
The mine produced 9.57Moz of gold during 2018. The mine site includes three metallurgical plants, along with a recovery plant for ore processing. The estimated ore reserve at Driefontein as of December 2017 was 5.272Moz.
The Kusasalethu gold mine operated by Harmony Gold Mining is located 75km west of Johannesburg, on the West Wits Line near Carletonville, Gauteng, South Africa. It exploits the VCR up to a depth of 3.38m below the surface.
Kusasalethu was formerly known as Elandskraal gold mine. Operational since 1978, Elandskraal was comprised of two mines namely Elandsrand and Deelkraal. The Kusasalethu operation comprises twin vertical and twin sub-vertical shaft systems. It employs conventional mining methods in a sequential grid layout. The extracted ore is processed at the nearby Kusasalethu plant.
As of December 2018, the proven reserves of Kusasalethu mine were estimated at 857,000oz of gold grading 7.26g/t, while the probable reserves were 101,000oz of gold grading 5.3g/t. The mine produced 142,395oz of gold grading 0.193oz/t in 2018.
Operated by Harmony Gold Mining, the Moab Khotsong gold mine is located near Vaal River, South Africa. The mine is located approximately 180km south-west of Johannesburg near the towns of Orkney and Klerksdorp. It has been in production since 2003 and currently ranks as the fourth deepest mine in the world, with its mining depth ranging between 2.6km and 3.052km below the surface.
The mine exploits the Vaal Reef (VR) through three mining layers, namely the Top, Middle, and Lower Mines. Moab Khotsong employs a scattered mining method with an integrated backfill support system, along with bracket pillars.
The mine produced 162,000oz of gold grading 0.238oz/t in 2018. The ore reserve stood at 1.61Moz grading 9.9g/t as of December 2018.
The Kidd Creek copper/zinc mine, located 27km north of Timmins in Ontario, Canada, is the fifth deepest operational mine and the deepest base metal mine in the world. The mining depth at Kidd Creek extends up to 3km beneath the surface. The mine is owned and operated by Kid Operations, a subsidiary of Glencore.
Kidd Creek was discovered in 1963 and witnessed the start of open-pit operation in 1966, while underground production was started in 1972. The mine is operated with three shafts using blast hole stoping with cemented backfill. The ore is sent to the Kidd Creek Metallurgical Division at Hoyle, located 27km south-east, for processing.
A $111m extension project called Mine D Phase 2 was completed in December 2011, extending the mine’s life.
LaRonde Gold Mine
The LaRonde gold mine is located in the Abitibi region of northwestern Quebec, Canada. It is owned and operated by Agnico Eagle and has been producing since 1988. It is estimated to hold 3.08Moz of proven and probable reserves as of December 2018.
The mine uses longitudinal retreat and transverse open stoping methods to extract gold. Agnico initiated an extension programme at the mine to access the deeper part of the mine, which extended the mining depth to 3,008m below the surface.
Agnico is investigating various mining methods and ground support systems due to seismic events at the mine as the mining depth increases. During 2018, the company continued to develop a main ramp below 3.1km and commenced construction of an underground cooling plant.
The South Deep gold mine, owned and operated by Gold Fields, is the seventh deepest mine in the world. The South African gold mine extends up to 2,998m below the surface. Covering an area of 4,268ha, the mine is located 45km south-west of Johannesburg.
The deep underground mine comprises two shaft systems known as the South Shaft complex and the Twin Shaft complex. The mine switched from conventional mining to fully mechanised mining in 2008. The extracted ore is processed at a central metallurgical plant.
The managed mineral reserve at South Deep as of December 2018 was estimated to be 328Mt grading 5.32g/t of Au. The mine produced 2.04Moz of gold in 2018. Gold Fields is implementing a restructuring programme at the mine to address various operational challenges.
The mine has failed to meet mining and production targets despite numerous steps taken, including the improvement of the mining method, a training programme for workers, and outsourcing activities. Gold Fields plans to initiate further restructuring to transform the mine into a mechanised and well-organised operation.
Lucky Friday Mine
Located in northern Idaho, US, Lucky Friday is an underground mine containing silver, lead, and zinc. The mine is operated by Hecla Mining Company and is the eighth deepest mine in the world with its depth extending up to 2.6km.
Lucky Friday is part of the Coeur d’Alene Mining District in Shoshone County. It uses ramp access, cut and fill method. The mine was estimated to contain proven and probable reserves of 5.61Mt grading 14.4oz/t silver, 9.1% lead, and 4% zinc as of December 2018.
Construction of a fourth shaft was completed at the mine in 2017, which provided access to highest-grade mineralised material below the current workings to a total depth of 2.62km. The fourth shaft project is a key area of growth for the mine as it extends the mine life by 20-30 years and the operational depth to 2.9km in the future.
Creighton is an underground nickel mine located in Greater Sudbury, Ontario, Canada, and the ninth deepest mine in the world. It is also the world’s deepest nickel mine, with its mining depth extending up to 2.42km. Discovered in 1991, Creighton is owned and operated by Vale.
The first production from the Creighton open-pit was made in 1901. Underground operations commenced in 1906. Current mining methods include shrinkage mining and mechanised undercut-and-fill mining. The large-diameter blast hole method combined with vertical retreat mining has also been recently introduced. The extracted ore is crushed underground and sent by rail to the Clarabelle Mill for processing.
The mine produced 608,000t of ore grading 2.77% copper and 2.55% nickel in 2018. Exploration drilling carried out at Creighton in 2007 confirmed mineralisation at depth. The Creighton Deep exploration project doubled the proven and probable reserve to 32Mt grading 1.9% to 2.2% nickel and 2% to 2.3% copper.
Kopanang Gold Mine
Operated by Harmony Gold Mining, Kopanang is located in the Vaal River region in the Free State province of South Africa. The mine extracts gold from the Vaal and Crystalkop reefs at depths ranging from 1,350m to 2,240m.
Scattered mining comprising a single shaft system is used at Kopanang. Shaft sinking was commenced in 1977 while production was started in 1984. Gold is processed using both conventional semi-autogenous grinding and carbon-in-pulp (CIP) technology, which produces uranium oxide as a byproduct.
Kopanang is currently producing low-grade gold with mining activities shifting towards the west of the lease area. It is estimated to hold mineral resources of 3.02Moz and ore reserves of 0.36Moz as of December 2017.
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