The material contained in the tailings storage facilities (TSFs) and low grade stockpiles originates from the historic ore-bearing reefs mined by the West Wits, Vaal River, Buffelsfontein, Hartebeestfontein and Stilfontein gold mines.

Low grade stockpiles.
The low grade stockpiles consist of waste rock mined from underground workings, hoisted, transported and deposited via conveyor belts. The gold contained within these dumps was sourced from three areas namely:
- Minor reef intersected while accessing the primary reef
- Gold-bearing reef that was contained within small fault blocks that were exposed by off-reef development
- Cross-tramming of gold-bearing reef material to the waste tips.

Tailings storage facilities.
The TSFs consist of tailings material which originated from the processing of the underground ore from the various operations in the Vaal River area (Vaal Reef Surface), the various operations in West Wits area (West Wits Surface) and Buffelsfontein, Hartebeestfontein and Stilfontein gold mines (Mine Waste Solutions (MWS)). These gold mines are deep level gold mines, which predominantly extract the tabular, conglomeratic Vaal Reef (VR), Carbon Leader Reef (CLR) and Ventersdorp Contact Reef (VCR). The VR has been predominantly mined for gold in the past although the reef also contains uranium oxide. The same is true but, to a lesser extent, with the CLR and VCR. The material contained in the TSFs is fine in nature. The footprints of the MWS TSFs and Vaal River Surface operations TSFs cover an area of approximately 1,100ha.

The Vaal River Surface operations extract gold from the low grade stockpile material emanating as a by-product of the reef mining activities within the mines in the Vaal River area. The Mine Waste Solutions (MWS) feed sources (the tailings storage facilities (TSFs)) are scattered over an area that stretches approximately 13.5km north-south and 14km east-west. The West Wits Surface operations are located near the town of Carletonville.

Low grade stockpiles.
Bulldozers are used to create safe loading faces. The material is then loaded from the face onto rail hoppers or trucks by means of front-end loaders and transported to the relevant gold plants for processing.

TSFs.
The tailings are reclaimed using a number of hydraulic (high-pressure water) monitoring guns to deliver water at pressure, typically 27-30 bar, to the face. The tailings material is reclaimed by blasting the TSF face with the high-pressure water, resulting in the slurry gravitating towards pump stations. These monitoring guns can be positioned to selectively reclaim required areas from the TSFs. Bench heights are constrained by the force delivered from the monitoring gun nozzle and safety constraints. With sufficient pressure, face lengths of up to 25m can be reclaimed.
The pump stations are located at the lowest point of the dams to ensure that the slurry from the dams will gravitate towards the pump station from where it will be pumped to the processing plants.

Surface Operations comprise Vaal River Surface, Mine Waste Solutions (MWS) and West Wits Surface operations. The operations produce gold by processing surface material such as low grade stockpiles and the retreatment of tailings storage facilities (TSFs).

The mineral process is dependent on the source material: tailings material is pumped directly to a conventional carbon-in-leach (CIL) plant while hard rock material will go through comminution first, and then be processed through leach followed by carbon-in-pulp (CIP).

Carbon-in-leach (CIL).
Gold is leached from a slurry of ore with cyanide in agitated tanks and adsorbed on to activated carbon granules at the same time (when cyanide is introduced in the leach tank, there is already activated carbon in the tank and there is no distinction between leach and adsorption stages). The carbon granules are separated from the slurry and treated in an elution circuit to remove the gold.

Carbon-in-pulp (CIP) ........