Tailings Management Plan – Water-capping Technology
Syncrude Canada Limited’s (“Syncrude”) Aurora North oil sands processing plant and mine (“Aurora North”) received approval through a joint Alberta Energy and Utilities Board (“EUB”) and Government of Canada panel in 1997. Syncrude commenced production at Aurora North in 2001, and tailings treatment in 2013 using composite tailings (“CT”) technology.
In this decision, the AER considered Syncrude’s application pursuant to section 13 of the Oil Sands Conservation Act (“OSCA”) for approval of its tailings management plan (“TMP”) for Aurora North.
The application sought approval for Syncrude’s TMP from the present until 2050.
For the reasons summarized below, the AER approved Syncrude’s application, subject to terms and conditions (the “Approval Conditions”).
The Approval Conditions imposed by the AER addressed:
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stakeholder and indigenous community engagement;
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project-specific thresholds for both new and legacy fluid tailings;
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tailings treatment technology and deposit plans and updates, including mitigation measures and research, monitoring, evaluation, and reporting; and
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environmental effects and implications.
Aurora North’s TMP Approval and Conditions
The AER had concerns about the ability of Syncrude’s applied-for TMP to meet the Lower Athabasca Region: Tailings Management Framework for Mineable Athabasca Oil Sands’ (“TMF”) objectives, given the TMP being dependent on water-capping, a technology subject to further assessment, research, and future policy. In the AER’s view, its approval together with the Approval Conditions reflected TMF outcomes and set conditions that ensured appropriate information was captured in a timely manner to manage risk and make appropriate regulatory decisions at Aurora North.
Regulatory Scheme
The Government of Alberta regulates tailings under the TMF.
Tailings are a by-product of the process used to extract bitumen from mined oil sands and consist of water, silt, sand, clay and residual bitumen.
The AER regulates tailings from oil sands mining operations to ensure that the tailings are managed in an efficient, safe, orderly and environmentally responsible manner over their entire life cycle.
The AER applies a risk-based approach to regulating, where higher-risk activities receive the greatest regulatory oversight. Given the nature and scale of fluid tailings generated by oil sands mine operations and the ongoing research and development of tailings treatment technology, fluid tailings management is one of Alberta’s higher-risk industrial activities.
The AER noted the following regarding the TMF:
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The TMF’s objective is to minimize fluid tailings accumulation by ensuring that fluid tailings are treated and reclaimed progressively during the life of a project, and all fluid tailings associated with a project are ready-to-reclaim (“RTR”) within ten years of the end of mine life.
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The TMF establishes four outcomes: land use must be returned to Albertans, sustainable ecosystem, liability is minimized to Albertans, and environmental effects are managed.
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As part of the implementation of the TMF, the AER released Directive 085: Fluid Tailings Management for Oil Sands Mining Projects (“Directive 085”), which sets out requirements for all fluid TMPs, including both existing fluid tailings (i.e., legacy) and new fluid tailings.
Tailings Treatment Technology
Composite Tailings Technology
The AER authorized Syncrude to continue to use CT technology to treat fluid tailings. However, the AER found that CT technology treatment capacity at Aurora North was constrained by coarse sand availability due to competing construction and reclamation needs.
To meet long-term reclamation outcomes, the AER required Syncrude to provide the following information as part of its Environmental Protection and Enhancement Act (“EPEA”) life of mine closure plan and mine reclamation plan:
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capping material types, objectives, and implications;
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material balances for coarse sand and any other suitable capping materials;
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contingency plans for capping material shortages; and
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an assessment of the minimum sand cap thicknesses required to manage the groundwater table, manage tailings pore water flux, provide adequate tailings deposit strength and trafficability, and drainage.
The AER also required Syncrude:
(a) to provide in its annual reclamation progress tracking report the volume of coarse sand and suitable overburden available as capping material for the CT placement locations; and
(b) to submit a capping research plan by December 31, 2018, for its CT deposits.
Water-capping technology
Directive 085 requires that where water-capped fluid tailings technology is used to generate the inventory forecast in the profiles, an alternative tailings treatment technology must also be provided, including timeframes for implementation.
The AER prohibited Syncrude from placing any water, including industrial wastewater, above treated or untreated fluid tailings to create a water-capped pit lake, based on the following:
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Water-capping technology was subject to further assessment, research, and future policy and extensive research on water-capped tailings were continuing.
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If the feasibility of water-capped pit lakes was demonstrated and the Government of Alberta implemented policies permitting their use, Syncrude must apply to the AER to amend their approval.
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Syncrude may continue to plan on the basis that water-capped pit lakes are an option unless water-capped tailings technology proves not to be feasible and/or Government of Alberta policy does not allow it.
The AER has required Syncrude to plan for an alternative to water-capped pit lakes. Syncrude is required to describe, by December 31, 2018, how it will develop feasible alternative tailings treatment technologies and an implementation plan to treat the volume of fluid tailings that is proposed to be treated with water-capping technology. Should Syncrude continue to propose the use of water-capping technology, Syncrude must provide feasible alternative tailings treatment technologies and an implementation plan in the updated 2023 TMP.
Fluid Tailings Profiles and Project-Specific Thresholds
Based on Syncrude’s application, its legacy fluid tailings and new fluid tailings profiles indicated that all legacy fluid tailings would achieve RTR status by end of mine life (2040) and all new fluid tailings would achieve RTR in 2045, five years after end of mine life.
Although the AER found that Syncrude’s profiles met the TMF’s objective, the AER had a number of concerns with the profiles. The AER was concerned about the ability of Syncrude’s profiles to meet the TMF objective given the TMP depending on the use of water-capping technology.
The AER required that Syncrude submit by December 31, 2018, how it will develop alternative tailings treatment technologies and an implementation plan to treat the volume of fluid tailings that Syncrude proposed to treat with water-capping technology.
Given that water-capped pit lakes are prohibited, and water-capping technology is subject to further assessment, research, and future policy, the AER ordered Syncrude to provide, by December 31, 2023, a TMP that included updated legacy fluid tailings and new fluid tailings profiles.
Legacy Fluid Tailings Profile
Legacy fluid tailings are fluid tailings that existed before January 1, 2015. All legacy fluid tailings must be RTR by end of mine life.
The AER found that Syncrude’s legacy fluid tailings profile met the TMF’s objective because the existing volume of 108 Mm3 would be treated and would achieve RTR status by 2040, end of mine life. However, the AER was concerned about the ability of Syncrude’s legacy profile to meet the TMF’s objective, based on Syncrude’s reliance on water-capping technology.
The AER required Syncrude to submit an updated TMP by December 31, 2023, that includes an updated legacy fluid tailings profile.
New Fluid Tailings Profile
The TMF defines new fluid tailings as fluid tailings that are produced after January 1, 2015. All new fluid tailings must be RTR within ten years of end of mine life.
The AER found that Syncrude’s new fluid tailings profile would meet the TMF’s objective as all new fluid tailings were expected to achieve RTR status in 2045, five years after the end of mine life.
Syncrude was depending on using water-capping technology to achieve the TMF’s objective. In this regard, the AER had several concerns:
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It was unclear whether Syncrude’s new fluid tailings profile excluded fluid tailings volumes generated from froth transferred to the Mildred Lake mine from Aurora North.
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Although the TMF acknowledged that it might take more than three to ten years to accumulate the peak volume, Syncrude was proposing growth in tailings accumulation until reaching its peak accumulated volume in 2040.
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Syncrude had not demonstrated that the fluid tailings treatment capacity was equal to or greater than the new fluid tailings production rate as required by the TMF and Directive 085.
The AER required Syncrude to submit an updated 2023 TMP that includes an updated new fluid tailings profile. The updated profile must demonstrate the TMF’s objective is achieved and ensure treatment capacity is equal to or greater than the new fluid tailings production rate by December 31, 2027. The profile must also include the timing when RTR status is achieved and reflect all available information on water-capping technology.
Thresholds
With respect to thresholds, the AER explained that:
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The volume of accumulated fluid tailings is the primary indicator in the TMF used to manage and decrease liability and environmental risk resulting from the accumulation of fluid tailings.
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Triggers and a limit (“thresholds”) are set relative to the fluid tailings profiles.
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The thresholds are intended to ensure that fluid tailings are not accumulating beyond a volume or at a rate that precludes operators from meeting the TMF’s objective.
The three thresholds under the TMF are the profile deviation trigger, the total volume trigger, and the total volume limit:
(a) Profile deviation trigger:
(i) applies to both legacy fluid tailings and new fluid tailings profiles;
(ii) occurs when the volume of fluid tailings is growing 20 percent faster than that approved for the profile;
(iii) is based on when the fluid tailings volume growth is 20 percent higher than that in the approved profile; and
(iv) allows a five-year rolling average to account for year-over-year variability.
(b) Total volume trigger:
(i) applies to the new fluid tailings profile;
(ii) occurs when the volume of fluid tailings has exceeded its approved maximum accumulation and requires additional management action; and
(iii) is based on a level equal to 100 percent of the greater of the maximum approved fluid tailings volume profile or the end of mine life target.
(c) Total volume limit:
(i) under the TMF is the volume of fluid tailings above which it presents an unacceptable risk to the environment and potential long-term liability;
(ii) if exceeded will compromise the ability of an operator to have all of their fluid tailings in an acceptable management state (i.e., RTR) within ten years of the end of mine life. Therefore, the most severe management responses are initiated;
(iii) is based on 140 percent of the greater of the maximum approved fluid tailings volume profile or the end of mine life target; and
(iv) applies to the new fluid tailings profile.
To allow for year-over-year variability, the AER set the profile deviation trigger for Syncrude as a five-year rolling average of the annual profile deviation. The profile deviation trigger applied to both the legacy fluid tailings and new fluid tailings profiles.
The AER set the thresholds in accordance with the TMF and Directive 085, and therefore Syncrude was subject to a total volume limit and total volume trigger, in addition to the profile deviation trigger.
The AER recognized that the maximum approved fluid tailings volume was 130 Mm3. However, this peak volume only occurred in a single year, near the end of mine life. The AER determined that it would be inappropriate to set a total volume trigger and limit based on this one-time peak volume due to the inflated threshold it would create for the entirety of the profile. As per Directive 085, the AER will consider all the circumstances when considering appropriate management responses where a threshold is exceeded.
The AER set the total volume trigger at 113 Mm3 and the total volume limit at 158 Mm3.
Storage
With respect to storage of tailings deposits, the AER required Syncrude to report annually on the available storage capacity of each tailings deposit or pond that contains water or tailings and to estimate the storage volume requirements for the next five years.
Ready-to-Reclaim Criteria
Under the TMF and Directive 085, fluid tailings are considered RTR when they have been processed with an accepted technology, placed in their final landscape position, and meet RTR criteria.
RTR criteria are used to track the performance of a tailings deposit toward its ability to be reclaimed as predicted.
RTR criteria are intended to support the objective of reclaiming oil sands mining projects to self-sustaining locally common boreal forest ecosystems that are integrated with the surrounding area and consistent with the values and objectives identified in local, sub-regional and regional plans.
Two sub-objectives address different aspects of performance:
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Sub-objective 1: The deposit’s physical properties are on a trajectory to support future stages of activity.
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Sub-objective 2: To minimize the effect the deposit has on the surrounding environment and ensure that it will not compromise the ability to reclaim to a locally common, diverse and self-sustaining ecosystem.
The TMF and Directive 085 allow operators to develop RTR criteria that are suitable for their type of tailings, technology, deposit and future reclamation activities.
Under Directive 085, treated tailings that meet their applicable RTR criteria can be removed from the fluid tailings inventory because they are on a trajectory to meet long-term reclamation outcomes. In circumstances where RTR criteria are no longer met, or there is a deviation from the expected trajectory, Syncrude must identify the volume not meeting the RTR criteria and the degree of nonperformance.
Measurement and Averaging
Each treated tailings deposit must be measured to determine if the RTR criteria have been achieved. Directive 085 requires operators to submit a measurement system plan six months from the date of an approved TMP.
Syncrude was required to develop a measurement system plan that included the following:
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definitions of parameters for fluid tailings and RTR criteria measurements;
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reference to standards and procedures used to measure fluid tailings and treated tailings and RTR criteria;
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an explanation of and justification for measurement procedures that are unique to Syncrude and its plan;
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·evidence that the plan will address the measurement outcomes as per section 5 of Directive 085;
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an explanation of how each of the deposit’s RTR criteria will be measured using deposit sampling, calculated, and reported;
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a description of the tailings deposit sampling, measurement, and survey program; and
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justification of how measurement, sampling, and spacing intervals will:
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show the variation of the tailings deposit properties;
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verify that the tailings deposit is achieving RTR criteria; and
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identify any material in the tailings deposit that is not achieving RTR criteria.
The AER found that Syncrude’s proposed averaging process would obscure a meaningful understanding of the deposit volumes that have been treated unsuccessfully or were failing to improve as expected. The AER noted that a deposit might show excellent performance on average while a significant portion of the tailings deposit is underperforming and compromising the ability to reclaim.
The AER, therefore, required Syncrude to measure the volume of treated tailings based on deposit sampling. The deposit sampling must be sufficient to identify variability within the entire deposit.
Sub-objective 1: Solids Content
Syncrude proposed to use the solids content by weight of a deposit as a sub-objective 1 RTR criterion.
The AER found that solids content alone may not be sufficient to measure a deposit’s performance or its ability to meet future stages of reclamation activity and meet the objectives of the TMF.
The AER, therefore, required Syncrude, for each treated tailings deposit, to monitor and report annually, sands-to-fine ratio, effective stress, deposit consolidation, pore water pressure, clay types and percentage, and any other parameters considered relevant by the AER or Syncrude.
The AER determined that, given the additional monitoring and reporting required, the use of the solids content by weight of a deposit was an acceptable sub-objective 1 RTR criteria measure.
Sub-objective 2
Syncrude proposed sub-objective 2 RTR criteria related to monitoring:
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treated fluid tailings and fluid levels compared to design elevations;
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slope movement and pore pressure; and
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observation wells for occurrences of elevated chloride concentrations.
The AER did not approve Syncrude’s proposal of monitoring treated fluid tailings and fluid levels compared to design elevations, slope movement, and pore pressure as Syncrude did not provide sufficient supporting information.
Stakeholder and Indigenous Community Engagement
The TMF and Directive 085 describe the importance of transparency, engagement, and enhancing stakeholder and indigenous community understanding of fluid tailings management.
To ensure continued transparency, information sharing and involvement in tailings management, the AER required Syncrude to engage stakeholders and indigenous communities on tailings management activities undertaken pursuant to the approval.
The AER also required Syncrude to:
(a) hold an annual forum with stakeholders and indigenous communities regarding tailings management activities; and
(b) report to the AER annually on its engagement efforts.
Summary
The AER approved Syncrude’s TMP for Aurora North, subject to conditions.
