Kopanang

Overview

The Kopanang mine, located in the Free State province of South Africa roughly 170 km southwest of Johannesburg. It has been in production since 1984. The current mine lease incorporates an area of 35 square kilometers, directly west of neighbouring Great Noligwa mine and bound to the south by the Jersey Fault.

Kopanang exploits gold- and uranium-bearing conglomerates of the Central Rand Group of the Witwatersrand, the most important being the Vaal Reef. Gold is the primary commodity extracted with uranium oxide as a by-product. 

Due to a high degree of geological variability the underground mining method of choice is scattered mining.

In 2011, Kopanang mine produced 307,000 oz gold and had another 10.27 million ounces gold in mineral reserves.

Location

The Kopanang mine, located in the Free State province of South Africa roughly 170 km southwest of Johannesburg.

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.  

The Free State experiences a continental climate, characterized by warm to hot summers and cool to cold winters.  Mining is the province's major employer.

Geology & Mineralization

The primary reefs mined at Kopanang are the Vaal Reef (VR), the Ventersdorp Contact Reef (VCR) and the secondary Crystalkop Reef (C Reef). The Vaal Reef is the main reef horizon that is being mined.

The Vaal Reef is made up of a series of oligomictic conglomerates and quartzite packages developed on successive nonconformities. The conglomerate reefs dip 21 degree towards the south and occur in a 2,100 metres thick sedimentary sequence comprising the Central Rand Group.

The complex set of geological units is not developed everywhere, giving rise to lateral variations in reef character. As a result, several distinct facies have been identified, each with its own unique gold distribution and grade characteristics. At Kopanang, in particular, gold is intimately associated with narrow discontinuous bands of pyrobitumen that are present within the Stilfontein Facies of the Vaal Reef. Minor amounts of gold are hosted by the C Reef as well.

Total mineral resources (December 2011) was estimated at 24.58 million tonnes grading 12.99 g/t for 10.27 million ounces gold.

Mining & Operation

The gold bearing reefs are accessed via a twin shaft system to a depth of 2,324 metres.

The principal reef mined is the Vaal Reef. The ‘C’ Reef, a secondary reef located about 220 m above the Vaal Reef, is mined on a small scale.

The Vaal Reef, the primary reef mined, is exploited at depths of between 1,300 m and 2,600m below surface. Minor amounts of gold are also extracted from the secondary Crystalkop Reef, located about 250 m above the Vaal Reef.

Given the complexity of the geology, scattered mining is employed and the orebody accessed mainly via footwall tunnelling, raised on dip of the reef and stoped on strike.

Processing

The milling and treatment process uses conventional SAG and CIP technology. Kopanang feeds one of the two plant streams with predominantly Vaal Reef ore; the other stream is fed exclusively by Ventersdorp Contact Reef (VCR) from AngloGold’s Tau Lekoa mine. Both streams are augmented with low-grade ore from waste dumps. Throughput capacity is 417,000 tpm. Kopanang sends 15,000 tonnes of ore per month (about 8% of its output) to the Vaal River No. 8 gold plant.

Kopanang uses conventional semi-autogenously grinding and carbon-in-pulp (CIP) technology to process gold. Roughly 60% of Kopanang’s ore is treated in this plant. The balance is sent to the Noligwa Gold Plant and South Uranium plant by rail for gold and uranium extraction.

A waste washing plant to reduce dust by washing the fines from waste rock was commissioned in 2010.

Environment & Community

The mine successfully achieved recertification for both ISO 14001 and OHSAS 18001.

An environmental management system (EMS) is in place to address the environmental impacts of the operation, including water and energy consumption, dust levels and potential groundwater pollution from the waste rock dump. To address the dust issue, a waste washing plant was installed and will be fully commissioned in 2011, along with additional dust suppression systems. Storm-water catchment facilities will be put in place and 20ha of phyto-remediation woodlands planted in 2011. Numerous projects resulted in reduced energy consumption from 32Gwh per month in 2003 to 24.5Gwh per month in 2010. Additional projects to reduce consumption to 23.4Gwh per month are planned in 2011 and 2012.

Kopanang retained its ISO 14001 certificate following an audit conducted in August 2010. No environmental incidents were reported during the year.

There were four fatalities at the Kopanang mine during the year ended December 2011.