Selati TSF Decant Project

Selati TSF Decant Project

Foskor (Pty) Ltd.

Phalaborwa, South Africa

  • 70-m-high decant tower
  • 740 m sub-surface concrete outfall pipe
  • 2.6 km on-surface outfall pipeline
  • 2.6 km service roads
  • 25-m-deep rock blasted excavations
  • Robust mechanical and instrumentation equipment and systems
  • 3-way operating functionality (manual, automatic, remote)
  • Green design (no electricity costs and low maintenance)
Project Overview

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.

Project 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:

  • Feasibility study
  • Detail design (civil and structural)
  • Assistance to mechanical and instrumentation designs
  • Geology investigation
  • Geotechnical investigations
  • Compilation of specifications and tender documentation
  • Tender adjudication technical assistance
  • Construction supervision services