AngloGold Ashanti Settles with a Waterspider

The Multiflo Waterspider supplied by Weir Warman Africa is equipped with a submersible pump and integral
mechanical agitator. The floating unit allows more efficient light-duty dredging of settling ponds..
Settling ponds used for dewatering typically are drained and mechanical means then used to remove the silt. “This was a time consuming and costly exercise,” according to Ian Farquhar, dewatering manager at Weir Warman Africa. But at Klerksdorp in South Africa, AngloGold Ashanti is now using a Multiflo Waterspider which is the first such unit to be locally manufactured and commissioned by Weir Warman Africa. The Multiflo Waterspider will allow ongoing cleaning of the settling ponds with minimal fuss and interruption to normal activities.

Farquhar explained that the Multiflo Waterspider is essentially a flotation device used for light dredging of settling ponds. The floating platform allows two operators to be on board to facilitate the setting of the depth of the pump at any time. “The platform, built in two components, allows easy transportation as well as assembly and disassembly. This facilitates optimum flexibility in terms of where the pontoon is used.”

Measuring 3.5 m in diameter, the platform is seated on three heavy-duty flotation tanks which are specifically produced for this application and allow a total load-bearing capacity, including the structure, of 3 tons. “It was designed to take the loadbearing capacities of the equipment and operators into account while still having a lightweight construction to allow optimum dewatering,” Farquhar said.

The Multiflo Waterspider comprises a Warman SHW heavy-duty submersible pump with a robust integral mechanical agitator which is lowered into the silt to facilitate the agitation of the settled solids to create a consistent percentage of solids in suspension. The Warman SHW pump has a capacity of 45 liter/sec at a maximum head of 28 m. While it is not necessary for the operators to stay on the platform to regulate the depth of the pump, being present does enable them to move the pontoon around the pond in order to ensure that the pump does not foul up in the silt, said Farquhar. This facilitates more effective clearing of the settling dams.

“Apart from meeting Weir Warman Africa’s quality specifications the Multiflo Waterspider has also been manufactured to AngloGold Ashanti’s safety design and specifications,” Farquhar said. It is equipped with kick plates at the base of the platform to prevent slips and safety rails are fitted around the platform itself. It has a lifting gantry to facilitate installation and removal of the pump; and is also equipped with buoyancy aids. “In addition, we color-coded the Waterspider to the AngloGold Ashanti safety specification whereby the gantry is red, the top rail of the platform is yellow and the remainder is red and black,” he said.

Installed and commissioned in March 2009, the Multiflo Waterspider has produced a positive customer reaction and Weir Warman reports that an order for another two such Multiflo Waterspiders is imminent. Although this unit is considered as a standard product within the Weir Warman Africa dewatering product range, individual floating platforms can be customized to suit varying applications and sizes of dams and settling ponds using a vast range of pump types and models.

As featured in Womp 2009 Vol 06 -