In 2001, the Twistdraai Colliery determined the need for storage of fine coal slurry produced in their Coal Handling and Preparation Plant. An impoundment dam design was deemed to be the most suited to the site, and was located adjacent to the existing discard stack. In this design, coal fines slurry is stored behind a wall constructed of coal discard. The discard must be well compacted to ensure not only its mechanical strength as an impoundment, but also its resistance to spontaneous combustion. With this type of design, care must be taken to balance the size and shape of the impoundment wall with that of the basin, as freeboard between the wall and the retained fine coal slurry must be maintained at a safe level throughout the life of the dam.

Jones and Wagener have subsequently been involved with the design and construction supervision of several additional extensions to the facility. Being appointed to undertake the monitoring of the operations has enabled the performance of the dams to be tracked, and improvements to the basic design to be incorporated into later developments.

Location