WASTE & RECYCLING
Majuba ash disposal facility takes shape
The recently completed rehabilitation dam receiving stormwater from the western side of the tailings facility
Concor has passed the halfway mark on its project to extend the continuous ash disposal facility (ADF) at Eskom’s Majuba power station near Amersfoort, Mpumalanga. The ADF will accommodate ongoing ash generation until February 2036, ensuring that Majuba remains compliant with ever-stricter environmental regulations.
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he project is being conducted in a fully integrated joint venture with Midrand-based contractor Lubocon Civils on an 85%/15% split, with Concor holding the majority stake. To date, Concor has handed over Terrace 2A and is in the process of handing over one of the two rehabilitation dams. The construction of the extensive terraces – which measure 1.2 km long by 175 m wide – began with bulk earthworks, cutting down to a design level before constructing the various layers. These layers include 100 mm of filter sand, followed by a Class 2 geomembrane and two 150 mm layers of clay. This is covered by a double-textured 1.5 mm HDPE geomembrane, followed by a 300 mm coarse ash layer. Each liner terrace, constructed from stabilised ash, is broken
down into compartments of 5 m widths, located every 100 m. “Underneath these layers, we are constructing a network of herringbone subsoil drains with a leachate collection system, which will flow into a pollution control dam,” explains Mabandla Dlamini, contracts director at Concor. Specialist subcontractors have been used for the all-important lining beneath the dams, as well as the identification of any potential leaks. “The excavation and bulk earthworks for the pollution control and rehabilitation dams are followed by the construction of a subsoil drainage layer,” he says. “In addition to the geomembranes and layers of filter sand and impermeable clay, this layering includes 250 mm thick geocells, a ballast layer comprising 300 mm
thick cement-stabilised sand (8% by mass), and geocells.”
Water perimeter canals Enhancing the environmental controls are water perimeter canals around the whole facility to separate and channel clean and dirty water. These are lined with 100 mm geocells filled with 30 MPa concrete, controlling the stormwater in the area. “The canals play a vital role in reducing the risk of any washdown from the tailings facility,” Dlamini continues. Measuring up to 7 m in width, the total combined length of these canals will amount to more than 4 km. The Concor-Lubocon JV is also constructing 5.5 km of internal or monitoring road, with G5 and G7 materials sourced from commercial operations in Newcastle and Ermelo respectively.
The Area 2 terraces with bulk earthworks, layerworks and HDPE liner installation in progress
The eastern embankment earthworks, road layerworks, culvert construction, and concrete-lined canals
