Improving Fluid Fine Tailings Treatment for Placement in a Permanent Aquatic Storage Structure

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Oil sands fluid fine tailings (FFT) are a byproduct of oil sands mining with current stockpiles exceeding 1.2 billion cubic metres. Tailings are considered a major liability in oil sands mining due to environmental and financial challenges. Current estimates place the cost of treatment of existing stockpiles between $5B-10B. Tailings are treated using a variety of chemical, physical and mechanical methods. In 2018, Suncor Energy Inc., a major oil sands mine operator, commercialized a novel and proprietary tailings treatment approach named Permanent Aquatic Storage Structure (PASS). To support this program, Suncor and the Northern Alberta Institute of Technology (NAIT) Centre for Oil Sands Sustainability (COSS) propose to expand our existing collaboration to include novel chemistries relevant to PASS. PASS offers a potential step-change in the volume and cost of tailings treatment for Suncor. To date, Suncor has accumulated 273.3 Mm3 of total fluid tailings inventory and PASS offers the possibility of treating a significant portion of this in a cost-effective, and environmentally responsible manner. The PASS technology combines the use of a polymer flocculant and an inorganic coagulant applied during the tailings transport process. Coagulants supplement the well-understood action of flocculants through charge neutralization of particulate contaminants, accelerating the remediation process and leading to faster reclamation objectives. The proposed study will a) improve the screening methodology developed for chemistries being considered for PASS, b) streamline the protocol to reduce the costs associated with screening a new technology while retaining resolution on the key parameters of concern, and c) assist with the prediction of long-term geochemical and biogeochemical characteristics of the final aquatic ecosystem. This project will benefit Canada by enabling oil sands operators to reclaim decommissioned mines faster, more efficiently and at a lower cost.