Tailing Basin Effluent Water Clarification Facility
GEI functions as the design engineer of record for an iron ore tailings basin that receives 10,000 gallons per minute of tailings slurry from the processing plant. Due to inefficiencies with the original basin effluent treatment system a new effluent water clarification system was required.
Prior to 2016, the basin had two 125 ft diameter clarifiers and a large building with facilities for chemical feed and pumping facilities. The clarifiers were constructed during the 1970s and in recent years were becoming less efficient and inoperable at times due to equipment failures and upsets which created operating constraints for the tailings basins. The new design coordinated by GEI provided a completely indoor facility housed within a 100 ft wide x 140 ft long x 50 ft tall building.
Key Challenges
GEI was able to rapidly assemble a design team and complete planning, design, construction services, and start-up of the water clarification facility. The project was on a fast track schedule from the beginning and the urgency to complete the project on schedule was exacerbated when one of the two clarifiers at the facilities failed during the summer of 2014.
GEI was selected for preliminary design evaluation and final design engineering services for the project. Following the preliminary design evaluations, GEI developed recommendations and preliminary design concepts and project cost estimates for a high-rate, un-ballasted dual-train clarification system. Construction design details were subsequently developed, equipment was specified and ordered, the project was constructed, and on June 22, 2016, the project successfully started up.
Preliminary design evaluation work wasn’t completed until fall 2014 and this was followed up by several months of pilot testing. Final process selection wasn’t determined until early 2015. At that time GEI was tasked with getting construction plans ready so that the project could be bid and be under roof before winter set in. GEI convinced the owner to fast-track the bidding and procurement of process equipment and a pre-engineered building while other process and project design details were being completed. This allowed major equipment and the basic steel framework for the building to be ordered so that shop drawings could be ready at about the same time a general contractor was selected. Concurrent with the writing of major equipment procurement specifications, GEI completed the process design and worked with a sub-consultant for the design of the building and electrical systems. The project was advertised and bid off of preliminary plans and the project was awarded on schedule and work began July 5, 2015. GEI also convinced the owner to bid the site civil work separately so that site preparation work and the installation of more than one mile of influent piping could be installed ahead of time.
The successful start-up and operation of the water clarification system allows for rapid drawdown of the pond levels within the basins, if necessary, and efficient treatment of effluent compared to the former water clarification system.