High Fines Sand Tailings as a Novel Oil Sands Tailings Treatment Technology

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Extracting bitumen from Canada's oil sands generates large volumes of fluid fine tailings (FFT), a waste material that presents significant environmental and economic challenges to consolidation and remediation. With over 1,270 Mm³ of tailings inventory as of 2019, finding a responsible solution to tailings management is a top priority for the Canadian mining industry. Chemical company BASF has developed a novel technology that combines coarse sand grains with FFT into material composed of fine particles filling the interstitial voids between successively larger particles. The fractal nature of the resultant substrate - known as "High Fines Sand Tailings" (HFST) - closely resembles the original oil sand ore. Product development testing at BASF and independently verified at NAIT have shown that a completely integrated sand/fines matrix is created with HFST, and much more resistant to shear-intensive process conditions than other sand-based tailings treatment strategies such as Composite Tailings (CT). Unlike CT, where the undesirable segregation of fines from the treated material is common, high release water clarity is a hallmark of the BASF technology. While HFST has been demonstrated to give optimal performance under tightly controlled laboratory-scale conditions, it must also be proven to excel under field conditions. Several tailings properties, such as solid content, clay fraction, and water chemistry, are understood to impact the flocculation process. However, tailings operations are often run with little to no process control, meaning that any viable treatment method must be robust and provide good performance over a wide range of conditions. The present study focuses on determining the operating window for HFST, then applying the learnings in subsequently larger scales. First, a small-scale pilot will be conducted at a feed flow rate of 1m³/hr before proceeding to a full-scale field pilot, treating FFT at 200m³/hr. Moreover, the water released from HFST will be used to extract bitumen from oil sand ore, with bitumen recovery performance compared against incumbent process water. The project will also evaluate HFST technology's ability to treat a fresh oil sands tailings stream or mine wastes outside of the oil sands industry.