The new gravity decant system for the 1100 ha Selati tailings storage facility (TSF) for the Foskor Phosphate Mine consists of a 70 m high concrete intake tower, stainless and mild steel combination access staircase, 0.75 km sub-surface concrete encased outfall pipe, and 2.8 km of steel outfall pipe with service road.
The system is capable of decanting 900 l/s at peak flow rates. The gravity flow system does not require electric power supply for operations. The mechanical operating equipment PLC, in the operating room of the decant tower, is connected to the plant control room via Wi-Fi to enable the remote control functionality. The system is solar powered.
Knight Piésold’s Role
Knight Piésold was tasked by Foskor (Pty) Ltd. with the detail design of the complete decant system. For the construction phase, Knight Piésold provided the design, engineering support, quality assurance services, and site supervision where necessary. Knight Piésold followed a One Team approach to successfully complete the project by combining the expertise from the Johannesburg, Pretoria, Phalaborwa, and Windhoek offices in South Africa and Namibia.
The main roles undertaken include: