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Tailings Management Plan – Water-capping Technology

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In this decision, the AER considered Imperial’s application pursuant to section 13 of the Oil Sands Conservation Act (“OSCA”) for approval of its tailings management plan (“TMP”) for the Kearl Mine.

The application sought approval for Imperial’s TMP from the present until 2066.

For the reasons summarized below, the AER approved Imperial’s application, subject to terms and conditions (the “Approval Conditions”).

Background

Imperial Oil Resources Limited’s (“Imperial”) Kearl oil sands mine site (the “Kearl Mine”) received approval through a joint Alberta Energy and Utilities Board and Government of Canada panel in 2007. The Kearl Mine started production in April 2013, and tailings placement began at that time in the external tailings area (“ETA”)

Thickened tailings (“TT”) are created by processing tailings in a thickener, which results in the removal of water. This increases the density and reduces the volume of the fluid tailings. Imperial commenced tailings treatment in 2016 using its thickeners.

Approval Conditions

The Approval Conditions imposed by the AER addressed the following:

• stakeholder and indigenous community engagement;

• project-specific thresholds for new fluid tailings;

• tailings treatment technology and deposit performance plans and updates, including mitigation measures and research, monitoring, evaluation, and reporting; and

• environmental effects and implications.

Kearl Mine’s TMP Approval and Conditions

The AER had concerns about the uncertainties of Imperial’s tailings treatment technology and deposit performance. In the AER’s view, its approval of the TMP, together with the Approval Conditions, reflected the Lower Athabasca Region: Tailings Management Framework for Mineable Athabasca Oil Sands’ (“TM Framework”) outcomes. The AER considered that the Approval Conditions would ensure appropriate information was captured in a timely manner to manage risk and facilitate appropriate regulatory decision-making regarding tailings management at the Kearl Mine.

Regulatory Scheme

The Government of Alberta regulates tailings under the TM Framework.

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 TM Framework:

• The TM Framework’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.

• The TM Framework establishes four outcomes: land use must be returned to Albertans, sustainable ecosystem, liability is minimized to Albertans, and environmental effects are managed.

• As part of the implementation of the TM Framework, 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

Use of Thickeners

Imperial was placing TT treated by secondary chemical treatment in the East ETA. Imperial proposed to commence placement of TT in the in-pit area 2 (“ITA2”) in 2028.

The AER authorized Imperial to continue to use thickeners with secondary chemical treatment, subject to the following conditions:

(a)      that the thickeners with secondary chemical treatment or other selected treatment technologies achieve performance parity with other comparable technologies;

(b)     that Imperial provides the AER with assurance that the TM Framework’s objective and outcomes can be met where water-capping technology is not permitted; and

(c)      that Imperial ensures compliance with Directive 085 by providing an updated TMP by December 31, 2020. The TMP must describe how it will develop alternative tailings treatment technologies and an implementation plan to treat the volume of fluid tailings that Imperial plans to water cap.

The AER was concerned that the thickeners, secondary chemical treatment, and East ETA might not perform as expected due to the stage of the Kearl Mine operations and the limited performance data. The AER anticipated that Imperial would be in a position to employ mitigation measures (e.g., re-handling, additional treatment, capping with additional material) should the East ETA underperform or Imperial fail to achieve long-term reclamation outcomes.

Water-capping Technology

Directive 085 requires that, where water-capped fluid tailings technology is used to forecast tailings inventory profiles, an alternative tailings treatment technology must be provided, including timeframes for implementation.

The AER required Imperial to provide an updated TMP by December 31, 2020, describing how it will develop alternative tailings treatment technologies and an implementation plan to treat the volume of fluid tailings that Imperial plans to water cap.

The AER was concerned with Imperial’s proposed use of water-capping technology, noting that water-capping was subject to further assessment, research, and future policy. The AER required Imperial to provide an updated TMP by September 30, 2027, that included Imperial’s decision on water-capping technology.

Imperial was waiting for the results of Syncrude’s Base Mine Lake (“BML”) water-capping technology demonstration, however, has not provided sufficient information for the AER to determine if BML research will address Kearl Mine site-specific uncertainties such as the end-pit lake deposit and water cap design, including physical, chemical, and biological components.

The AER required Imperial, under its Environmental Protection and Enhancement Act (“EPEA”) approval, to provide the following:

• the applicability of Syncrude’s BML research to Imperial’s circumstances;

• how Imperial will address uncertainties and risks where BML research is not applicable; and

• the research related to human health risk assessment and long-term chemistry and minerology for end-pit lakes.

Capping Material Availability

The AER found that Imperial’s ability to meet TM Framework outcomes and future reclamation outcomes would be compromised if there was insufficient capping material. Therefore, the AER imposed conditions to ensure that Imperial had adequate coarse sand tailings, or other suitable capping material, available to support its activities.

Adequate capping material, such as coarse sand tailings, is necessary for landform contouring and stability. It provides, among other things, increased tailings deposit strength and trafficability, manages settlement, controls the location of the groundwater table, controls surface water drainage, and prevents tailings pore water from contaminating reclaimed areas.

Imperial requires capping material for the following activities:

• infill beaching;

• construction for the purposes of building dams and tailings containment structures; and

• capping tailings deposits.

As part of the Approval Conditions, the AER required Imperial to provide the following information as part of its EPEA life of mine closure plan and/or mine reclamation plan:

• capping material types, objectives, and implications;

• material balances for coarse sand and any other suitable capping materials; and

• contingency plans for capping material shortages.

The AER also required Imperial to submit a capping research plan by December 31, 2020, for its TT deposits. Imperial’s research must provide timely and site-specific information concerning capping material needs and availability. If there were a capping material shortage, Imperial would need to adjust its tailings treatment technology selection to ensure the TM Framework’s and long-term reclamation outcomes can be achieved.

Imperial is also required to continue to report on capping and stability as part of its tailings research report required under its EPEA approval.

Fluid Tailings Treatment Technology

To address the concerns related to technology and deposit performance, the AER required Imperial to report annually on the technology performance and the East ETA deposit performance, including:

(a)      providing mitigation measures to rectify technology that is not performing as expected;

(b)      assessing the performance and benefits of secondary chemical treatment; and

(c)      providing information confirming technology continuous improvement and development.

To understand if segregation of TT is occurring and whether mitigation measures need to be implemented, the AER required Imperial to monitor, on a quarterly basis, solids content and sands-to-fine ratio of the TT following secondary chemical treatment. Imperial is required to provide a summary of these monitoring results annually.

The AER expressed concern about Imperial’s treatment technology capacity being sufficient to treat tailings at the Kearl Mine. The AER noted that the Kearl Mine was currently producing 220,000 barrels per day (“bpd”). Under existing OSCA and EPEA approvals, Imperial could increase production to 345,000 bpd by 2027, followed by stable production thereafter.

As part of the updated 2020 TMP, the AER required Imperial to assess, describe, and propose the selected treatment technologies that ensure the treatment capacity of the selected technologies would be equal to or greater than the production rate of fluid tailings.

Fluid Tailings Profile and Project-Specific Thresholds

The fluid tailings profile represents the volume of fluid tailings that are not RTR.

 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 accepted Imperial’s request to deem all fluid tailings as new fluid tailings, based on the following:

(a)      the volume of legacy fluid tailings was small (5 million m3);

(b)      the Kearl Mine was at an early stage of operations; and

(c)      the legacy and new fluid tailings being placed in the ETA were indistinguishable from one another.

Therefore, the AER did not require Imperial to provide a legacy fluid tailings profile.

New Fluid Tailings Profile

New fluid tailings are fluid tailings that are produced after January 1, 2015. All new fluid tailings must be RTR within ten years of end of mine life.

Based on Imperial’s technology and deposit performance assumptions, the AER found that its new fluid tailings profile met the TM Framework’s objective, as all new fluid tailings were predicted to achieve RTR status by 2066, within ten years after the end of mine life. Imperial’s new fluid tailings profile is authorized.

Nevertheless, the AER addressed these issues with respect to Imperial’s new fluid tailings profile:

(a)      the profile was based on Imperial’s conservative assumptions regarding treatment technology performance and tailings deposit performance, as Imperial needed more time to verify its tailings treatment technology and deposit performance;

(b)      as operations progressed, the new fluid tailings profile might not represent the actual performance of the Kearl Mine’s treatment technology and tailings deposit; and

(c)      Imperial’s end of mine life target appeared to be more than the five years of fluid tailings accumulation, contrary to the requirement under the TM Framework and Directive 085 that the end of mine life target be equivalent to five years or less of fluid tailings accumulation.

To address these issues, the AER required Imperial to submit an updated new fluid tailings profile in the updated 2020 TMP by December 31, 2020. The updated new fluid tailings profile must:

• incorporate current tailings treatment technology and tailings deposit performance data;

• incorporate predicted tailings treatment technology and tailings deposit performance; and

• have an end of mine life target that is no greater than five years accumulation of fluid tailings production.

Thresholds

With respect to thresholds, the AER explained that:

• The volume of accumulated fluid tailings is the primary indicator in the TM Framework used to manage and decrease liability and environmental risk resulting from the accumulation of fluid tailings.

• Triggers and a limit (thresholds) are set relative to the fluid tailings profiles.

• 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 TM Framework’s objective.

The three thresholds are the profile deviation trigger, the total volume trigger, and the total volume limit:

(a)      Profile deviation trigger

(i)        occurs when the volume of fluid tailings is growing 20 percent faster than that approved for the profile;

(ii)       is based on when the fluid tailings volume growth is 20 percent higher than that in the approved profile; and

(iii)      allows a five-year rolling average to account for year-over-year variability.

(b)      Total volume trigger

(i)        occurs when the volume of fluid tailings has exceeded its approved maximum accumulation and requires additional management action; and

(ii)       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)        is the volume of fluid tailings above which it presents an unacceptable risk to the environment and potential long-term liability; and

(ii)       is based on 140 percent of the greater of the maximum approved fluid tailings volume profile or the end of mine life target.

To allow for year-over-year variability, the AER set the profile deviation trigger for Imperial as a five-year rolling average of the annual profile deviation.

The total volume trigger and limit are based on the greater of the maximum approved fluid tailings volume profile or end of mine life target, as per the TM Framework and Directive 085. As Imperial’s maximum approved fluid tailings volume was 180 million m3, which was greater than the end of mine life target, the AER set the total volume trigger at 180 million m3 and the total volume limit at 252 million m3.

Tailings Solvent Recovery Unit Tailings

The AER did not permit Imperial to place tailings solvent recovery unit (“TSRU”) tailings in any deposit except the West ETA at this time. Because the location of TSRU tailings was restricted, Imperial’s measurement system plan is required to include identification of substances of concern in TSRU tailings, and measurement location and measurement methodology for the substances of concern. Given limited data, the AER was uncertain how Imperial would manage the risks to the surrounding environment and long-term reclamation outcomes from TSRU tailings placed in the West ETA.

Storage

With respect to storage of tailings deposits, the AER required Imperial to report annually on the available storage capacity of each tailings deposit or pond that contained water or tailing and to estimate the storage volume requirements for the next five years.

Ready-to-Reclaim Criteria

Under the TM Framework 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.

The TM Framework and Directive 085 allow operators to develop RTR criteria that are suitable for their type of tailings, technology, deposit and future reclamation activities.

In this case, the AER did not accept Imperial’s proposed RTR criteria. The AER found that Imperial’s proposed RTR criterion:

(a)      did not provide assurance that the deposit’s physical properties were on a trajectory to support future stages of activity in an appropriate timeframe;

(b)      did not consider the characteristics of the TT that would be placed in the tailings deposit, as the criterion was proposed prior to secondary chemical treatment; and

(c)      was not time bound with respect to the trajectory to 65 percent solids content.

Sub-objectives

Two sub-objectives address different aspects of performance:

• Sub-objective 1: The deposit’s physical properties are on a trajectory to support future stages of activity.

• 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.

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, Imperial must identify the volume not meeting the RTR criteria and the degree of non-performance.

Sub-objective 1: Solids Content

Imperial proposed to use solids content as a sub-objective 1 RTR criterion.

The AER required Imperial, 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 Imperial.

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.

The AER directed Imperial to update the RTR trajectory and criteria for each type of deposit, including the East ETA TT deposit in the updated 2020 TMP.

Sub-objective 2

Imperial proposed the following sub-objective 2 RTR criteria for the East ETA:

• the groundwater monitoring program conducted as per the EPEA approval;

• industrial wastewater control systems have been constructed to capture potentially process affected surface water and return it to the ETA; and

• design reports and annual performance reports for each structure (i.e., dams).

The AER approved Imperial’s proposal to use its existing groundwater monitoring program as a sub-objective 2 RTR criterion for the East ETA.

The AER did not approve:

(a)      Imperial’s proposed use of the industrial wastewater control system as a sub-objective 2 RTR criterion, based on the AER’s finding this would only mitigate risks to the surrounding environment while the control systems were actively operating; and

(b)      Imperial’s proposed sub-objective 2 RTR criterion of design reports and annual performance reports for each structure (i.e., dams). Imperial did not describe a clear relationship between design reports and annual performance reports and sub-objective 2.

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.

The AER required Imperial to develop a measurement system plan that included the following:

• definitions of parameters for fluid tailings and RTR criteria measurements;

• reference to standards and procedures used to measure fluid tailings and treated tailings and RTR criteria;

• an explanation of and justification for measurement procedures that are unique to Imperial and its plan;

• evidence that the plan will address the measurement outcomes as per section 5 of Directive 085;

• an explanation of how each of the deposit’s RTR criteria will be measured using deposit sampling, calculated, and reported;

• a description of the tailings deposit sampling, measurement, and survey program; and

• a justification of how measurement, sampling, and spacing intervals will:

(a)      show the variation of the tailings deposit properties,

(b)      verify that the tailings deposit is achieving RTR criteria, and

(c)      identify if any material in the tailings deposit is not achieving RTR criteria.

The AER required Imperial to measure the volume of treated tailings that met the RTR criteria based on deposit sampling. The AER expected deposit sampling to be sufficient to identify variability within the entire deposit. The AER prohibited Imperial from using an annual average for the entire deposit to determine the volume of treated tailings meeting RTR criteria.

Stakeholder and Indigenous Community Engagement

The TM Framework 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 Imperial to engage stakeholders and indigenous communities on tailings management activities undertaken pursuant to the approval.

The AER also required Imperial 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 Imperial’s TMP for the Kearl Mine, subject to the Approval Conditions.