Gamsberg's world-class TMF
Gamsberg has the largest high density polyethylene (HDPE)-lined TMF in South Africa and will accept 3.55Mt of tailings a year. It was named the Most Outstanding Geotechnical Project of 2018 by the South African Institute of Civil Engineers.
A number of best practices relating to design overview; location selection; geo-membrane selection; geotechnical/ hydrogeology investigations; deposition method: cyclone vs spigot; storm water management; environmental management; stability analysis; digitalisation; closure planning and documentation were implemented from the start.
Given the sensitive environment in which Gamsberg operates, the various potential impacts of the TMF were given serious consideration. Especially important was protecting the groundwater. The TMF is fully lined with a 1.5mm HDPE liner to prevent any polluted water from reaching natural sources; and a continuous impermeable rock armour was constructed on the outside slope of the TMF to prevent clean rain water run-off being contaminated with tailings. This also helps to minimise the wind dispersion of the tailings.
In line with our overall digitisation drive at Gamsberg, a number of measures were implemented, including:
- temperature probes underneath the liner to measure if the tailings become heat-generative; and
- wireless vibrating wire piezometers, delivering real-time water level data. Trigger levels are built in to give warning if the phreatic surface (the level below which the ground is completely saturated with water) rises above limits.