Grant: CCI Applied Research and Development Grants

Fluid fine tailings (FFT) are formed during the deposition of tailings in ponds from the extraction process of oil sands mining operations. Despite considerable investments in research, the treatment and reclamation of FFT remains a concern today with over 1.3 billion cubic meters of FFT present in the oil sands. Companies have spent billions of dollars in research to develop effective ways to treat and reclaim FFT however despite this effort, further research is needed as a silver bullet has not yet been found to support terrestrial reclamation. Lime is a known soil stabilizer used to strengthen clay rich foundations into supporting heavier loads. Lime has been identified as a potential method of strengthening clay dominated tailings deposits but the challenge is how to deliver the treatment in a cost-effective manner at the scale & depth required in oil sands as current application methods require the use of heavy equipment and are most suitable for deposits <10m thick. To fill this gap for the benefit of the sector and all Canadians, NAIT’s Centre for Oil Sands Sustainability (COSS) and Graymont, a global leader in lime and limestone solutions, will examine whether adding lime during in-line flocculation can generate a deposit with higher strength and permeability than with incumbent technology (polymer only or alum + polymer). If in-line addition of lime is successful in providing this soil-stabilizing benefit it could significantly increase the strength and stability of the deep cohesive deposits being created in the oil sands today, therefore allowing them to be reclaimed into the desired upland boreal forest ecosystem. Graymont, the oil and gas sector, and all of Canada will benefit from this work due to the great potential for reduction of the environmental impact of treated fluid fine tailings. In addition, Graymont will benefit from a potential large new customer pool. Globally, the opportunity to treat soft deposits in-line with lime may assist with dewatering and dredging operations in other soft deposits.