Savuka

Overview

Savuka mine is located about 18km south of the town of Carletonville and along with Mponeng and Tau Tona mines it forms part of AngloGold Ashanti’s West Wits operations. It is located immediately north of Mponeng and northeast to Tau Tona.

The mine exploits the Carbon Leader Reef (CLR) at depths varying from 2,600m to 3,500m below surface. The Ventersdorp Contact Reef (VCR), which is about 700m above the CLR, has largely been mined out and mining operations on the VCR horizon ceased in 2010.

Savuka has converted from a longwall configuration to a sequential grid mine and most of the mine’s current production is derived from the CLR. The Ore Reserve at the mine is largely exhausted and minimum mining operations are currently taking place.

In 2011, the mine produced 49,000 ounces of gold at $864 total cash cost per ounce.

The mine’s infrastructure was mothballed at the end of 2011. Ongoing maintenance is required in order to continue water pumping activities for AngloGold Ashanti’s remaining mines in the immediate vicinity.

Location

Savuka is located near the town of Carletonville on the border between the South African provinces of Gauteng and North West. It is 43 km northeast of the city of Potchefstroom on the northwestern rim of the Witwatersrand Basin.

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.

Gauteng – the Place of Gold in local Sesotho language - is South Africa’s smallest province but at the same time the most populous. It is the country’s most important economic hub and contributes heavily in the financial, manufacturing, transport, technology and telecommunications sectors, amongst others.

Geology & Mineralization

The CLR is a thin, tabular, auriferous quartz pebble conglomerate formed near the base of the Central Rand Group. The CLR is on average 20cm thick and has been divided into three stratigraphic units. Economically the most important is Unit 1 which is present as a sheet-like deposit over the whole mine. Unit 2 is a complex channel deposit that is presently only being mined in the south and west areas of Savuka. The reef may be over 2m thick where Unit 2 is developed. Unit 3 is preserved below Unit 1 in the southern parts of Savuka and is the oldest of the three CLR stratigraphic units. 

The VCR comprises a quartz pebble conglomerate (up to 5m thick) capping the top-most angular unconformity of the Witwatersrand Supergroup. The topography of the VCR depositional area is uneven and consists of a series of slopes and horizontal terraces at different elevations. 

The reefs at Savuka are cross-cut by faults and intrusive dykes that displace the reef horizons. The faulting, in conjunction with the numerous intrusives that also intersect the orebody, is responsible for most of the risk inherent with deep-level gold mining, since seismicity is associated with these geological features. 

As of December 2011, proven and probable reserves were estimated at 2.36 million tonnes grading 7.90 g/t for 600,000 ounces gold. At the same time some 4.76 million tonnes ore classified as indicated reserve contained an estimated 3.64 million pounds.

Mining & Operation

Savuka is a mature mine that is approaching the end of its productive life.

The mine exploits the Carbon Leader Reef (CLR) at depths varying from 2,600 m to 3,500 m below surface. The Ventersdorp Contact Reef (VCR), which is about 700 m above the CLR, has largely been mined out and mining operations on the VCR horizon ceased in 2010.

Savuka has converted from a longwall configuration to a sequential grid mine and most of the mine’s current production is derived from the CLR. The Ore Reserve at the mine is largely exhausted and minimum mining operations are currently taking place.

The mine was placed on care and maintenance during 2011 following a shaft accident that damaged underground infrastructure in May 2009. Limited operations continued throughout 2011 using previously developed reserves.

Parts of the Savuka deposit will be accessed from the neighbouring Mponeng operation.

Processing

The Savuka gold plant treats ore from Savuka and Tau Tona and also processes dump material.

Ore from Savuka is treated through semi-autogenous grinding (SAG) mills, followed by a conventional gold leach with liquid oxygen injection. Gold extraction is by means of CIP technology. The recovery of gold from carbon for Mponeng, Savuka and the TauTona mines, is done at the Mponeng’s central elution plant and smelthouse, which forms part of the Mponeng Plant. Advanced AARL elution circuits are used, followed by stainless steel electrowinning. Smelting is done both by electric and induction furnaces.

In 2011, the mine produced 49,000 ounces of gold at $864 total cash cost per ounce.

An opportunity to upgrade marginal ore material was initiated in the West Wits area at the Savuka gold plant and the exercise has proven to be successful. The Savuka Marginal Ore Dumps  is currently being screened and oversize material of greater than 65mm is being stockpiled and will be made available to external parties once permission has been granted to do so by the Department of Mineral Resources.

Environment & Community

Savuka has received the following certifications:

• ISO 14001 – Environment; and

• OHSAS 18001 – Occupational health and safety. 

Socio-economic development is an essential aspect of the South Africa region’s business strategy, both from the perspective of compliance, to ensure retention of mining licences, and also because a downward trend in the region’s gold production profile together with a strategy of removing employees from high-risk areas will inevitably lead to reductions in our labour force over the medium term. 

Following extensive stakeholder engagement, the region has designed a framework to integrate community development into core business activities, while providing support for national and international development policies and objectives, particularly those addressing youth unemployment.