Gauteng, South Africa
Gold Fields Ltd – 100%
Gold - 273 koz (2011)
|Deposit Type||Conglomerate gold reef type deposit|
|Reserves & Resources||
Gold - 39.6 Moz (Proven & Probable, December 2011)
|Mining Method||Drift & bench, Longhole stoping|
|Processing Method||Crushing, grinding, gravity recovery, cyanide leach|
|Mine Life||To 2064|
SAG & Ball mills; Knelson concentrators (2); Gemini table; cyclones; cyanide leach circuit; gold recovery circuit
P.O. Box 57
Last updated: May 16, 2013
South Deep gold mine is located 45 km southwest of Johannesburg in South Africa. It mines the gold reefs of the Witwatersrand Basin.
South Deep is a long-life, deep-level mechanized gold mine operating at between 2,000 and 3,000 meters below surface. The mine, which is still undergoing development, was acquired by Gold Fields in 2006. The mine employs innovative underground mining methods and technologies that have the potential to influence the long-term commercial viability of the company’s mining operations in South Africa. In 2011, the mine was awarded the first place in the Mining and Industrial category at the Southern African Institute of Steel Construction (SAISC) Steel Awards 2011 for the new steel headgear at South Deep.
In 2011, the company invested US$275 million in the development of the South Deep mine and metallurgical plant expansion. The mine is expected to produce 700,000 ounce annual run-rate by the end of 2015, while the processing plant would be able to process 330,000 tonnes per month starting with the second half of 2012.
In 2011, the mine produced 273,000 ounces of gold at $1,073 per ounces total cash costs. The mining operation is expected to become cash positive in 2013. Mine life is estimated to 2064.
The mine is located in the Witwatersrand Basin near the town of Westonaria, Gauteng Province, South Africa.
It is approximately 45 km southwest of Johannesburg. Access to the mine is by road. The nearest railway siding is at Westonaria. This is the urban area of South Africa. Transportation and services are excellent.
South Africa is a country located at the southern tip of the African continent. It is a multi-ethnic nation and has diverse cultures and languages. Mining in South Africa has been the main driving force behind the development of Africa’s most advanced and richest economy. Gold was discovered in Witwatersrand in 1886.
South Deep is located in the Far West Rand Goldfields situated on the northwestern rim of the Witwatersrand Basin. The Witwatersrand Basin comprises a 6,000 metre thick sequence called the Witwatersrand Supergroup, which consists of predominantly detrital sedimentary rocks interspersed sporadically with auriferous and uraniferous quartz pebble conglomerates, termed reefs, especially in the upper parts of the succession classified as the Central Rand Group.
South Deep’s primary economic target is the Upper Elsburg Reef package with the Vantersdorp Contact Reef (VCR) being a secondary economic target.
The Upper Elsburg reefs subcrop below the VCR in a north-north-east trend and comprise multiple stacked reef horizons that form part of an easterly divergent clastic wedge.
The VCR comprises a quartz pebble conglomerate (up to 5m thick) capping the top-most angular unconformity of the Witwatersrand Supergroup.
Mineral reserves were estimated at the end of 2011 to contain 39.6 million ounces gold.
The South Deep mine represents the most significant gold development project in South Africa. It is a long-life, deep-level mechanized gold mine operating at between 2,000 and 3,000 meters below surface.
In 2011, the company invested US$275 million in the development of South Deep which is on schedule in all areas.
The scale, depth and positioning of the South Deep ore body raises a number of unique technological challenges. In order to meet those challenges the company made considerable investments, which include:
- The application of fully mechanized, deep underground mining, which has significantly improved productivity and reduced employee exposure to fall-of-ground and heat.
- Accelerated implementation of the horizontal de-stress cut methodology is speeding up the rate at which the mine can open up the ore body. This mitigates risks associated with the geotechnical stress regime and will improve future production volumes.
- Establishment of a specialized, on-site training facility, using advanced training packages and electronic simulators to produce a cadre of world-class underground mechanized miners. This is expected to be commissioned in early 2012.
- The maximization of existing hoisting capacity through the refurbishment and conversion of the linked South Shaft complex.
- High-efficiency auxiliary fans are to be used at the mine site thus reducing the electricity consumption.
In 2011, the Vent Shaft was completed and would be commissioned in the second half of 2012. The shaft would greatly increase the hoisting capacity. The same year also saw the completion of the head gear at the Vent Shaft, using one of the largest fabricated steel head gear frames in the world.
In 2012, development and production ramp-up is to continue at South Deep.
The milling circuit includes a semi-autogenous grinding (SAG) mill for primary milling and secondary milling conduced in an overflow ball mill, with classification done using a cluster of cyclones.
The recovery of free gold is achieved using two Knelson concentrators, with the concentrate being tabled using a Gemini Table in the smelthouse.
The cyclone overflow is thickened before the slurry reports to the leach circuit. The leach circuit has six mechanically agitated tanks each with 3000 cubic meter volume.
In 2011, the company initiated the expansion of the South Deep Metallurgical Plant, which is being constructed on an accelerated schedule – with commissioning planned for the second half of 2012. This will increase capacity from 220,000 to 330,000 tonnes per month.
In 2011, South Deep produced 273,000 ounces of gold. The mine is expected to produce 700,000 ounce annual run-rate by the end of 2015.
Tailings from the South Deep would be stored in a new large volume Centralized Tailings Storage Facility (CTSF). The facility sits on strata that pose only minimal risks of groundwater contamination. The CTSF was completed in 2011.
Plans are also being finalized for the implementation of an ice-based underground cooling system by 2015.
Gold Fields has embraced sustainable development as a business imperative, which is reflected in its vision, values and strategy. It has introduced structures that encourage a networked interface between disciplines like safety, health, environmental engineering, nature environment, risk, stakeholder engagement, legal and communication. This approach has allowed Gold Fields to capitalize on synergies and to avoid duplication in the realm of sustainable development.
The company is also actively involved in the management of the impact of mining activities on local farming, including compensation and resettlement.
Gold Fields South African operations are very important not only for their shareholders abut also for all other stakeholders: government, local communities and, most critically, their approximately 41,400 employees and 4,300 contractors.