Eight of the ten deepest mines in the world reside in a particular region of South Africa, while the remaining two - Kidd Creek and Creighton - are both located in Ontario, Canada. Mining-technology.com profiles the top ten deepest mines in the world.
Mponeng Gold Mine
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 2.4km to more than 3.9km below the surface by the end of 2012. Ongoing expansions have resulted in deeper digging at Mponeng, pushing the record to beyond the four kilometre mark.
The ore reserve at Mponeng stood at 13.7 million ounces (Moz) as of December 2012. The mine produced 405,000oz of gold in 2012. It is currently undergoing expansion to extend the mine life beyond 2040.
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. The gold plant complex and the shafts were commissioned in 1986.
TauTona Gold Mine
TauTona, AngloGold Ashanti's gold mine in the West Wits region of South Africa, ranks as the second deepest mine in the world.
Although mining at TauTona currently takes place at depths ranging from between 1.85km to 3.45km, its mining depth was extended to 3.9km underground with the addition of a secondary shaft in 2008.
TauTona mining operations began in 1962 with the construction of 800km of tunnels. The mine is currently operated with three shafts.
AngloGold Ashanti started changing the mining method at TauTona from longwall to scattered-grid mining in 2007.
TauTona's mine life is expected to end in 2015. It produced 189,000oz of gold in 2012. The estimated ore reserve stood at 1.713Moz as of December 2012.
Savuka Gold Mine
Savuka gold mine, also located in the West Wits region of South Africa and operated by AngloGold Ashanti, is the third deepest mine in the world. The mine exploits the gold contained reefs at a depth of more than 3.7km.
The mining method at Savuka was recently converted from longwall to sequential grid mining. Savuka shares a common processing plant with the TauTona mine.
The shafts and infrastructure at Savuka were damaged by a seismic event in 2008. The mining operations were, however, completely restored in 2011.
Savuka produced 37,000oz of gold in 2012. The mine was left with 0.56 million oz of gold reserves by the end of that year. AngloGold Ashanti is considering incorporating Savuka into the neighbouring TauTona for accessing the remaining resources of Savuka.
Driefontein Mine
The Driefontein mine, owned by Gold Fields, 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 fourth deepest mine in the world with its depth extended up to 3.4km.
The Driefontein mine operation could be traced back to 1952. The mine consists of eight producing shaft systems extracting ore from three reefs, namely Ventersdorp Contact Reef (VCR), Carbon Leader Reef (CLR) and the Middelvlei Reef. Driefontein uses a combination of longwall and scattered mining methods.
The mine produced 709,800oz of gold during 2010. The mine site includes three metallurgical plants, along with a recovery plant for ore processing. The estimated ore reserve at Driefontein as of December 2012 was 4.369Moz.
Kusasalethu Gold Mine
The Kusasalethu gold mine operated by Harmony is located 75km west of Johannesburg, on the West Wits Line near Carletonville, Gauteng, in South Africa. It is currently the fifth deepest mine in the world as it exploits the Ventersdorp Contact Reef (VCR) up to a depth of 3,276m below the surface.
Kusasalethu was formerly known as Elandskraal gold mine. Elandskraal, which started operation in 1978, was comprised of two mines namely Elandsrand and Deelkraal. The Kusasalethu operation comprises of twin vertical and twin sub-vertical shaft systems. The mine employs conventional mining methods in a sequential grid layout. The extracted ore is processed at the nearby Kusasalethu plant.
The Kusasalethu mine contained a proven reserve of 2.7Moz of gold grading 0.208oz/t and a probable reserve of 4.4Moz of gold grading 0.172oz/t as of December 2012. The mine produced 181,105oz of gold grading 0.137oz/t in 2012. A total of 5,237 employees and 979 contractors were engaged in the mining operation during the same year.
Moab Khotsong Gold Mine
Moab Khotsong gold mine is one of AngloGold Ashanti's Vaal River operations in the South Africa. The mine is located around 180km south-west of Johannesburg near the towns of Orkney and Klerksdorp. The mine is in production since 2003. It currently ranks as the sixth deepest mine in the world, with its mining depth ranging between 2.6km and 3.054km below 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.
The mine produced 162,000 ounces of gold grading 0.238oz/t in 2012. The ore reserve stood at 6.61Moz grading 10.02g/t as of December 2012. AngloGold Ashanti engaged 19 underground drilling machines at Moab Khotsong in 2012, to increase the mineral resource base and extend the mine's life up to 2040.
South Deep Gold Mine
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 2,995m below surface. The mine, covering an area of 4,268ha, is located 45km south-west of Johannesburg.
The deep underground mine comprises of 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 2012 was estimated to be 39.1Moz. The mine produced 270,000oz of gold in 2012. It is undergoing a major development project to increase its annual production to about 700,000oz by 2016. The mine life of South Deep is expected to be extended up to 2092.
Kidd Creek Copper and Zinc Mine
The Kidd Creek copper / zinc mine, located 27km north of Timmins in Ontario, Canada, is the eighth deepest mine and the deepest base metal mine in the world. The mining depth at Kidd Creek extends up to 2,927m beneath the surface. The mine is owned and operated by Xstrata, which acquired it from Falconbridge in 2006.
Kidd Creek was discovered in 1963 and witnessed the start of open pit operation in 1966. Underground production started in 1972. The mine is operated with three shafts. The mining method used is blasthole stoping with cemented backfill. The ore is sent to the Kidd Creek Metallurgical Division at Hoyle, located 27km south-east of the mine for processing.
The mine produces more than 7,000t a day. A $111m extension project called Mine D Phase 2 was completed in December 2011, which is expected to extend the mine's life up to 2018. The Mine D project extended Kidd Creek below the shaft No 3.
Great Noligwa Gold Mine
Great Noligwa gold mine operated by AngloGold Ashanti in the Vaal River region of South Africa is located 15km southeast of the town of Orkney. It currently ranks as the ninth deepest mine in the world. The average mining depth of Great Noligwa is 2.4km below surface and the maximum mining depth is 2.6km below surface.
The mine primarily exploits the Vaal Reef (VR) with a twin shaft system. The Crystalkop Reef (CR) comprises the secondary economic horizon for the mine. The mining method employed at Great Noligwa is pillar mining.
The proven and probable reserve of Great Noligwa as of December 2012 stood at 390,000oz of gold grading 8.75g/t. The mine produced 84,000oz of gold in 2012 employing 2,985 permanent employees and 78 contractors.
Creighton Mine
Creighton, an underground nickel mine located in the City of Greater Sudbury, Ontario, Canada, is the tenth deepest mine in the world. It is also the world's deepest nickel mine, with its mining depth extending up to 2.5km. The mine is owned and operated by Vale. The mine was discovered in 1991.
The first production from the Creighton open pit started in 1901. Underground operation commenced in 1906. Current mining methods include shrinkage mining and mechanised undercut-and-fill mining. The large-diameter blasthole method combined with vertical retreat mining has also been introduced recently. Extracted ore is crushed underground and sent by rail to the Clarabelle Mill for processing.
The mine produced 797,000t of ore grading 1.80% copper and 1.84% nickel in 2012. Exploration drilling carried out at Creighton in 2007 confirmed mineralisation at depth. The Creighton Deep exploration Project is believed to have almost doubled the proven and probable reserve to 32Mt grading 1.9% to 2.2% nickel and two percent to 2.3% copper.
