The VR is the primary economic horizon at Kopanang and the Crystalkop Reef (C Reef) is the secondary economic horizon, which contributes less than 2% of the total mining volume. Both reefs are narrow tabular deposits forming part of the Witwatersrand Supergroup and are stratigraphically located near the middle of the Central Rand Group. The VR lies approximately 255 m below the C Reef.

The major fault systems affecting Kopanang are the oldest north-westerly dipping Zuiping faults, and the younger Shaft and Jersey fault systems, which dip to the south east. The primary economic horizon at Tau Lekoa, Jonkerskraal and Weltevreden is the VCR. The VCR dips between 20° and 30° at Tau Lekoa, whereas the dip at Jonkerskraal is steeper (>30°) and gentler at Weltevreden (average of 15°).

The VCR in this locality is structurally complex due to disruption by a number of dykes and faults. The major faults of post-Ventersdorp age present tend to be normal, trending NNE-SSW direction and these include the Schoonspruit and Nooitgedacht faults, both of which have displacements of over 100 m. Two dextral faults with lateral movement (wrenching) in the order of 675 m and 170 m have been mapped on Tau Lekoa and projected into the adjacent project areas. There are also a number of intrusives present, which vary in age from pre-Ventersdorp through to Karoo in age.

The Witwatersrand gold deposits are of the “Quartz Pebble Conglomerate Au-U type”. These are also referred to as “placer gold and uranium in ancient conglomerate”, or “palaeo-placer gold and uranium” deposits. The mineralised horizons, or reefs, are essentially oligomictic to polymictic, matrix to pebble-supported conglomerate in which vein quartz pebbles predominate. The matrix, which essentially is quartzitic, accommodates the gold and uraninite largely as disseminated clastic particles.

A geological model is employed to delineate variations (either lateral or vertical) in characteristics of the VR and C Reef. The current geological model thus subdivides the VR and C Reef into homogeneous zones based on geological, sedimentological and grade characteristics.
The VCR, which thickens up to 5 m, caps the uppermost angular unconformity of the Witwatersrand Supergroup. Due to the angular unconformity at the base of the VCR the footwall stratigraphy youngs towards the NE, with the various formations sub-cropping against the VCR in a NE-SW direction. The VCR eventually subcrops below the Karoo Supergroup on the western side of Weltevreden.

The gold-bearing quarzitic and conglomerate bands of the Witwatersrand Supergroup are characterised by rounded pebbles set in a mineralogically complex matrix. The pebbles are predominantly vein quartz, but can include jasper, quartzite, shales and schist, and typically do not contain appreciable mineralisation. The VR and C Reef are examples of the reefs characterised by discontinuous layers of kerogen at their base. There is a strong association between the kerogen and gold, which is found on its surface, as well as filling cleats and open spaces between filaments. There are two main varieties of gold. One is (possibly) primary gold, occurring as rare inclusions in detrital grains of massive pyrite, or as detrital grains and nugget like particles in the matrix. The second is a younger generation, possibly the result of metamorphism and recrystallization virtually in situ, which seems to have replaced fine-grained matrix material.

Kopanang is a deep level mature gold mine and the planned production rate of 66 ktpm is significantly lower than the installed capacity of the infrastructure. Two gold-bearing horizons, viz. VR and C Reef, are accessed through a single shaft system which descends to a maximum depth of 2 334 m, while the main working levels are situated between 1 300 m and 2 064 mbs. The Kopanang ore body is geologically complex and scattered mining methods are employed. Access to the orebody is mainly by footwall haulages.

The Kopanang Mine has a well-established underground infrastructure. Its underground ore transportation system includes a rail track system and features a unique “Big Mamma” underground locomotive, which is designed to transport high volumes of broken ore to the shaft at the depth of 2,334 meters. The Kopanang Mine is accessible by a single shaft that is 10.6 meters in diameter, which is one of the largest in the South African gold mining industry. The shaft has a rock hoisting capacity of 260,000 tons per month and is divided into separate compartments for men and material and rock hoisting.

The broken ore is hoisted in a conveyance to surface by the winder, and transported from shafts to silos by conveying belts for stockpiling. The ores in silos are then transported to West Gold Plant by trains operated by a third party.

Mined ore delivered by train or trucks from our mines is offloaded onto a stockpile, and fed to the apron feeder by a loader or directly into the apron feeder bin, which transfers it to a mill stockpile (silo). The ore is then fed to the mills via vibrating feeders that are interlinked with the controls of the mills. The ore is then milled and classified in the hydro-cyclones where an overflow product size of 80% -75 micrometers is targeted.

West Gold Plant has two ball mills with a combined capacity of 160,000 tons per month.

All the ore delivered to West Gold plant.

After milling the ore is classified in the hydro-cyclones where an overflow product size of 80% -75 micrometers is targeted. The slurry is then fed into the thickeners and settled with the addition of flocculent and lime. A density value of 1,500 kilogram per cubic meter and a pH value of 10.5 are targeted. The pH assists with control of cyanide consumption.

Leaching/Pre-Leach, CIL/CIP Process and Acid Wash
The thickened slurry is pumped into pre-leach vessels where oxygen and cyanide are added to dissolve gold out of the ore. The dissolution of gold is also aided by mechanical agitation.

The dissolved gold is adsorbed by carbon in the six carbon-in-pulp adsorption vessels. The CIP process is counter-current with dissolved gold in the pulp flowing downstream and activated carbon moving upstream.

The dissolved gold is adsorbed by carbon in the eight carbon-in-leach vessels. In this process gold is ........