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Thin Lift Evaporative Drying – Surface Area Utilization

Overview

Managing mature fine tailings (MFT) is a critical step in oil sands mine reclamation. In the majority of MFT management processes chemicals commonly applied in municipal water treatment facilities are utilized to help separate water from the fine tailings. The chemicals, referred to as polymer flocculants, attach themselves to the clay particles in the MFT causing them to bundle together and separate from the water.

Applying a thin lift evaporative drying approach to chemically treated MFT requires deposition in areas specifically constructed for the technology. The water released by the chemical treatment is returned to the tailings storage facilities where it will be reused in the bitumen extraction process. The resultant dewatered material is next subjected to evaporative drying and can be reclaimed in the same location where it was deposited or transported to another location for final reclamation.

This project involved testing a mechanical Jacking Header in Suncor’s Tailings Reduction Operations (TROTM). The goal of the project was to measure the properties of the dried tailings over time, and determining potential depositional area optimizations and footprint reductions with the Jacking Header system compared to conventional earth berms.

The Technology

The Jacking Header is a hydraulically jacked structure capable of matching the rate of rise of tailings eliminating the need to raise, and in some cases install, earthen berms or excavate deposited mature fine tailings (dMFT.) Its design, with bilateral spigotting capabilities, results in the use of one pipeline setup for deposition within two placement areas eliminating the need for intra deposit placement berms.

Objective

The project sought a better understanding of how to design and operate a self-raising header structure, eliminate re-handling dMFT and reduce footprint requirements for MFT thin lift evaporative drying strategies. This included determining the production rates at a given quality that could be expected for a full scale commercial deployment of a Jacking Header asset using an optimized depositional approach.

Potential/Actual Environmental Benefits

The project supports TROTM, and equivalent MFT treatment technologies, in creating trafficable, stackable deposits, improving reclamation and reducing land use.

Outcomes

  • Deployment of Jacking Header
  • Determination of best practise deposition to maximize production yield
  • Quantification of quality (density/solids content/CWR) at given yield
  • Data collection on Freeze-thaw consolidation behaviour of deposit performance post deposition.