OPERATIONS:
Operations span over four different companies, namely AngloGoldAshanti Ltd., GoldFields, Harmony and Sibanye; they mostly lay in the Witwatersrand Basin Area.
AngloGoldAshanty – AngloGold Ashanti’s South Africa Region comprises four deep-level mines located at the Vaal River and West Wits operations. The Vaal River mining operations include two mine sites - Kopanang has a single shaft system to a depth of 2,334m; it exploits the Vaal Reef almost exclusively; Moab Khotsong has a single shaft system mining to a depth of 3,100m - and a share milling and treatment circuit. The West Wits operations are: Mponeng Mine is the world’s deepest gold mine, and extracts the Ventersdorp Contact Reef (VCR) via a twin-shaft system at depths of between 2 800m and 3 400m below surface. Ore is treated and smelted at the mine’s gold plant; and TauTona Mine makes use of a three-shaft system and predominantly extracts the Carbon Leader Reef (CLR), and the VCR on a smaller scale through the use of technology; TauTona mines at depths of between 2 700m and 3 300m below surface.
GoldFileds – Intermediate to deep-level gold mine (> 2,000m below surface) exploiting auriferous palaeoplacers (reefs), namely the conglomerates that comprise the Upper Elsburg Reefs of the Mondeor Formation and the Ventersdorp Contact Reef (VCR). South Deep Gold Mine. The workings are accessed from the surface through two shaft systems (main and ventilation shafts), of which the main shaft comprises a single-drop to a depth of 2,998m, the vent shaft to 2,947m and the South Shaft Complex, which is a subvertical system (four shafts) to 95 level at a depth of 2,786m. South Deep Gold Mine utilises one tailings storage facility (TSF) known as the Doornpoort TSF. The TSF footprint is designed to accommodate the LoM tonnage excluding backfill. South Deep Gold Mine operates one on-property gold plant. The comminution circuit comprises two stage milling with a free gold recovery circuit. Gold recovery is carried out using a conventional leach/carbon-in-pulp (CIP) circuit.
Harmony – It comprises Nine underground mines (Bambani, Doornkop, Joel, Kusasalethu, Masimong, Pakhisa, Target 1, Tshepong, Unisel and one open-pit Kalgold.
Bambanani, has two surface shafts: mining is conducted at a depth of 2 365 metres. Activities at the mine focus on the Basal Reef and are limited to shaft pillar extraction. The ore mined is sent to Harmony One Plant for processing.
Doornkop is a single-shaft operation and mining is conducted at a depth of 1 978 metres. The operation focuses on narrow-reef conventional mining of the South Reef. The ore from the operation is processed at the Doornkop plant.
Joel mine comprises two shafts, the North and South shafts. The primary economical reef horizon at Joel is a narrow tabular Beatrix Reef deposit which is accessed via conventional grid development. Mining is conducted at a depth of 1 452 metres. The ore is processed at the Joel plant.
Kusasalethu mines the Ventersdorp Contact Reef as its main ore body. The mine comprises twin vertical and twin sub-vertical shaft systems and uses conventional mining methods in a sequential grid layout. Mining is conducted at a depth of 3 388 metres, making it Harmony’s deepest mine. Ore mined is treated at the Kusasalethu plant.
Masimong complex comprises an operating shaft (5 shaft), and a second shaft (4 shaft), which, although closed for mining, is used for ventilation, pumping and as a second outlet. Masimong exploits the Basal Reef and the B Reef. Mining is conducted at a depth of 2 050 metres. Ore mined is processed at the Harmony One plant.
Phakisa mine has two shafts, the main Phakisa shaft and the Nyala shaft. Phakisa exploits the Basal Reef. Mining is conducted at a depth of 2 426 metres. Ore mined is processed at the Harmony One plant.
Target 1 mining operations comprise one primary underground mine, with a depth of approximately 2 945 metres. While most of the ore extracted comes from mechanised mining (massive mining techniques), conventional stoping is still employed primarily to de-stress areas ahead of mechanised mining. Ore mined is processed at the Target plant.
Tshepong mining is conducted at a depth of 2 349 metres. The mine uses conventional undercut mining in the Basal Reef while the B Reef is exploited as a high grade secondary reef. Ore mined is processed at the Harmony One plant.
Unisel mining is conducted at a depth of 2 153 metres below surface. Conventional scattered mining and pillar reclamation takes place to access the Basal, Leader and, to a lesser extent, the Middle reefs. Ore mined is processed at Harmony One plant.
Kalgold is an open-pit mine: mining takes place from the A Zone pit. Ore mined from the pit is processed at a carbon-in-leach plant located at Kalgold.
Sibanye – It comprises two main complexes: Beatrix and Kloof.
Beatrix complex consists principally of underground mine with nominal surface reserves represented by surface rock dumps (SRDs) accumulated during the operating history of the mine. Current mine infrastructure consists of three producing shaft complexes. Mining is focused on open ground and pillars of differing reef horizons with the deepest operating level some 2,055m below surface. Beatrix makes use of two gold processing plants, both treating underground and surface material.
Kloof operations is a complex of intermediate to ultra-deep-level mines, predominantly mining the Ventersdorp Contact Reef, at depths of between 1,300m and 3,350m below surface. Kloof's operations comprise five producing shaft systems and two metallurgical gold plants.
Kloof Plant 1 comprises three-stage crushing, open-circuit rod mills for primary grinding and closed-circuit pebble mills for secondary milling. This is followed by cyanide leaching, filtration, zinc precipitation and smelting. Kloof Plant 2 currently treats all of Kloof's underground ore. Reef is trucked and conveyed to a central stacker pad, which feeds two SAG mills equipped with variable-speed ring motor drives. Milling is followed by cyanide leaching, CIP and treatment at an independent elution and smelting facility. The elution facility was upgraded in June 2001 and again in October 2003 to process loaded carbon from KP1 and the former KP3 (Libanon) plant. The upgrade included the installation of continuous electro-winning sludge reactors.
REFERENCES:
AngloGlodAshanti Limited, Integrated Report, 2016
AngloGlodAshanti Limited, Sustainable Development Report, 2016
AngloGoldAshanti Limited, Vaal River Operational Report, 2016
AngloGoldAshanti Limited, West Wits Operational Report, 2016
GoldFields, Integrated Annual Report, 2016
GoldFields, GRI G4 Content Index, 2016
Harmony, Integrated Annual Report, 2016
Harmony, Operational Performance, 2016
SibanyeGold, Integrated Annual Report, 2016