De-licensing of Oil Sands Tailings Dams. Technical Guidance Document

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  • Some of the oil sands tailings dams, licensed under the Alberta dam safety regulations, have reached the end of their service life and under a responsible environmental stewardship should be closed and reclaimed. The path to closure and reclamation requires de-licensing of these structures, since dams require active intensive risk management programs. There is currently limited technical guidance on the requirements and on the process to de-license a tailings dam. This document presents a de-licensing framework, based on a performance and risk-based approach, to take oil sands tailings dams to a stage such that they can be de-licensed as dams and considered as solid mine waste structures.The Dam Safety Office quickly became a national leader and demonstrated its value to the oil sands industry when in 1975, it appointed the Tar Island Tailings Dyke Design Review Panel. Tar Island Dyke was the first tailings dam in the oil sands industry. The Canadian Dam Association (CDA) grew substantially out of the strength developed in Alberta, British Columbia and a few other jurisdictions. One of the most important publications from CDA are their recommended Dam Safety Guidelines, which form the basis for the approvals of dam safety not only in Alberta, but also many other jurisdictions in Canada and elsewhere. I have expressed the view that dam safety systems applied to the Alberta oil sands industry are the best in the world (Morgenstern, 2010). A number of dams licensed by the regulator in accord with the Dam Safety Guidelines have now ended their active service life and others are close to it. For example, Tar Island Dyke is now transformed into a solid and trafficable landscape with advanced reclamation, after about forty years of service. However, if the license that governs the operation of the dam is not ultimately removed, it will require ongoing monitoring and reporting. Active care is not needed after closure design has been implemented and is in conflict with the desire of all stakeholders to remove obstacles to passive care and ultimate certification of the reclaimed landscape. Removing the license to operate as a dam does not imply any sense of imminent neglect. Instead, the dam is transformed into one of many landforms that have to be monitored and reclaimed to a level consistent with regulatory closure requirements. Removal or breaching, are options open to consideration when de-licensing a water dam. However, these may be impossible or inappropriate for de-licensing a tailings dam since processes, such as erosion, may result in unacceptable consequences. Therefore, other than ensuring the dam does not have ponds large enough to qualify for licensing, there appeared to be no precedents to follow to de-license tailings dams in the oil sands, which are now moving toward more advanced stages of reclamation. In response to this limitation, a group of interested stakeholders was convened to address this issue. Similar to the Special Committee established by APEGA, the group included owners, regulators and technical experts, operating in a consensual way, and supported by their organizations. This effort has been rewarded by the document presented here that provides a practical way forward to de-license oil sands tailings dams. We should be appreciative of the public service offered by all who contributed to this Technical Guidance Document.

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    Conditions of Use Oil Sands Tailings Dam Committee (2014). De-licensing Oil Sands Tailings Dams. Technical Guidance Document. 45 p. Copyright © 2014. Oil Sands Tailings Dam Committee. Permission for non-commercial use, publication or presentation of excerpts or figures is granted, provided appropriate attribution (as above) is cited. Commercial reproduction, in whole or in part, is not permitted without prior written consent. As a professional courtesy, the authors would appreciate being notified as to how and where their work is being used, cited and implemented. An email with particulars to is sufficient. The end user assumes all risks associated with any interpretation of, or implementation based upon, this work.