Oil sands mining effluent

Environment and Climate Change Canada (ECCC) is exploring options to manage the accumulation of oil sands process-affected water in tailings ponds located in the Athabasca Oil Sands Region (AOSR).

Background

Oil sands deposits consist of bitumen bound tightly with sand. Where these deposits exist close to the surface, oil sands mining operators extract the deposits using open-pit mining methods. The extraction process uses hot water to separate the bitumen from the sand. This process produces tailings as a by-product.

Oil sands tailings are a mixture of sand, silt, clay, residual bitumen, and contaminated process-affected water. Process-affected water contains many compounds that may be harmful to the environment if released without treatment. These include:

• Metals
• Salts (inorganic ions)
• Naphthenic acids
• Petroleum Hydrocarbons
• Polycyclic aromatic hydrocarbons (PAHs)
• Other organic compounds

Oil sands mining operators store tailings on-site in large tailings ponds. In tailings ponds, the fine tailings particles slowly separate out, and settle at the bottom of the pond. Then, the process-affected water in these ponds is re-used in the extraction process. Despite heavy water re-use by operators, additional fresh water is still required on an ongoing basis. In the decades since oil sands mining began, this added freshwater use, together with captured precipitation in the tailings ponds has led to the accumulation of substantial process-affected water volumes.

Crown-Indigenous Working Group

Canada is committed to Indigenous Reconciliation and the United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP). For the people and wildlife who live in the oil sands region, the Athabasca River’s importance is paramount. Many Indigenous communities have stated that they rely on the continued health of the Athabasca River watershed for their livelihoods.

In recognition of the importance of the Athabasca River to Indigenous communities, ECCC and nine Indigenous communities established a Crown-Indigenous Working Group (CIWG) for the potential Oil Sands Mining Effluent Regulations in 2021. This group is leading the work to explore options to manage the accumulation of oil sands process-affected water in tailings ponds located in the AOSR. The group will co-develop discussion papers for release to the public and other materials and recommendations for a path forward.

One of the options under consideration is the potential development of regulations that would authorize treated effluent release from oil sands mines. The Fisheries Act prohibits the deposit of deleterious substances in water bodies containing fish or in any place where the deleterious substances may enter any such water, unless authorized by a federal regulation. No such regulation is in place for oil sands mines, meaning there is currently no federal authorization to release oil sands process-affected water as effluent.

If developed, regulations would allow releases of treated effluent into the Athabasca River and its tributaries under certain conditions. Regulations would be developed with strict protective standards reflecting the best available scientific information and Indigenous knowledge. While regulatory development is in the early stages, CIWG is exploring effluent quality standards that could include:

• Rules on quality of a release
• Conditions on testing, monitoring and reporting of releases

Engagement and Reports

Introduction to the Crown-Indigenous Working Group for the Potential Oil Sands Mining Effluent Regulations (June 2023)

This document:

• informed interested parties of current and future work of the CIWG
• facilitated the collection of public input
• had a comment period that closed on October 6, 2023

What We Heard Report (May 2024)

This document provides a summary of feedback collected from the Introduction document.

Oil Sands Process Affected Water Best Available Technology Assessment Report (December 2022) (prepared by a third-party contractor and available in English only)

Assessment of Alternatives to Discharge of Oil Sands Mine Water (November 2023) (prepared by a third-party contractor and available in English only)

Engagement sessions

Engagement sessions with organizations and community representatives will be ongoing as work advances. If you are interested in participating, please contact sb-os@ec.gc.ca to be added to the mailing list or for any questions.

Note: please read our privacy statement.

Relevant Links

Acts

• Fisheries Act
• Impact Assessment Act
• Canadian Environmental Protection Act, 1999

Topics

• Fisheries Act Registry
• Canada-Alberta oil sands environmental monitoring

Regulations

• Proposed Coal Mining Effluent Regulations
• Metal and Diamond Mining Effluent Regulations

Contact us

Environment and Climate Change Canada
Regulatory Development and Analysis Section
Mining and Processing Division
351 boul. St-Joseph
Gatineau QC K1A 0H3
Email: sb-os@ec.gc.ca