Success Stories - Extraction and Tailings
Suncor’s Steepbank mine opened in the fall of 1998, with the implementation of several new technologies for ore preparation, ore transport and separation cell design. A large volume of high grade ore at the Steepbank mine presented some significant processing problems, which were traced by CanmetENERGY to the presence of oxidized, or surfactant rich bitumen in the ore.
This type of (surfactant rich) bitumen chemistry resulted in poor froth product quality in spite of a high grade oil sands feed. CanmetENERGY developed an extraction process modification after identifying the problem bitumen chemistry and the associated chemical solution to the problem (see the bitumen froth picture). Without the novel extraction technology developed as a part of the federal oil sands extraction research program, over 30 million tonnes of ore, representing about 20 million barrels of oil would have had to have been wasted.
Since this success, every operating company has had ore evaluated for the presence of oxidized or degraded bitumen in order to improve extraction recovery.
Work in the early 1990’s at the University of Alberta on consolidated tailings showed that geotechnically, this process might produce a trafficable deposit (deposit which can support heavy equipment) from a portion of the fluid fine tailings that are accumulating as a result of surface mined oil sands development.
The chemistry behind the consolidated tailings process was investigated as part of the CanmetENERGY research program, and based on favourable results from the laboratory, Suncor commercialized the consolidated tailings process. This tailings treatment is based on a manipulation of the properties of the clay tailings with gypsum, a process that can reduce the water required to produce a barrel of bitumen by 25%. Our research work was critical to the commercialization effort because the manipulation of the clay behaviour required a change in process water chemistry. This change in process water chemistry had to be compatible with the extraction process, and we were able to quantify the operating conditions under which the consolidated tailings process could be implemented. Further work on this process demonstrated that a wide range of chemicals (aside from gypsum) could be used in the consolidated tailings process. These include organic polymers and carbon dioxide. Canadian Natural Resources Ltd., an oil sands operator, will be using carbon dioxide in their non-segregating tailings process, building upon the research work done at CanmetENERGY’s facilities.
The consolidated tailings, or non-segregating tailings processes are two success stories that promise to reduce the amount of water used to produce a barrel of bitumen and at the same time create a solid landscape where the fluid fine tailings can be reclaimed as the original boreal forest. These are not the only technologies available, and our research program is studying many alternatives, all of which have various advantages and preferred applications, and all of which promise to convert the fluid fine tailings to dry stackable tailings, significantly decreasing the water consumption associated with surface mined oil sands development. These processes span variations of the consolidated tailings process using various chemical treatments, to drying processes, land farming, centrifugation, or novel tailings deposition techniques.
Commercial implementation of the dry stackable tailings created from whole tailings shown in the following pictures will still require research and technical support, and we are participating in that commercialization effort.
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