Wapisiw Lookout, reclaimed site of the oil sands industry’s first tailings pond, which started in 1967. The area was restored to a solid surface in 2010 and now functions as a 220-acre watershed. Photo courtesy Suncor Energy

From the Canadian Energy Centre 

By CEC Research

Mines demonstrate significant strides through technological innovation

Tailings are a byproduct of mining operations around the world.

In Alberta’s oil sands, tailings are a fluid mixture of water, sand, silt, clay and residual bitumen generated during the extraction process.

Engineered basins or “tailings ponds” store the material and help oil sands mining projects recycle water, reducing the amount withdrawn from the Athabasca River.

In 2023, 79 per cent of the water used for oil sands mining was recycled, according to the latest data from the Alberta Energy Regulator (AER).

Decades of operations, rising production and federal regulations prohibiting the release of process-affected water have contributed to a significant accumulation of oil sands fluid tailings.

The Mining Association of Canada describes that:

“Like many other industrial processes, the oil sands mining process requires water. 

However, while many other types of mines in Canada like copper, nickel, gold, iron ore and diamond mines are allowed to release water (effluent) to an aquatic environment provided that it meets stringent regulatory requirements, there are no such regulations for oil sands mines. 

Instead, these mines have had to retain most of the water used in their processes, and significant amounts of accumulated precipitation, since the mines began operating.”

Despite this ongoing challenge, oil sands mining operators have made significant strides in reducing fluid tailings through technological innovation.

This is demonstrated by reductions in “legacy fluid tailings” since 2015.

Legacy Fluid Tailings vs. New Fluid Tailings

As part of implementing the Tailings Management Framework introduced in March 2015, the AER released Directive 085: Fluid Tailings Management for Oil Sands Mining Projects in July 2016.

Directive 085 introduced new criteria for the measurement and closure of “legacy fluid tailings” separate from those applied to “new fluid tailings.”

Legacy fluid tailings are defined as those deposited in storage before January 1, 2015, while new fluid tailings are those deposited in storage after January 1, 2015.

The new rules specified that new fluid tailings must be ready to reclaim ten years after the end of a mine’s life, while legacy fluid tailings must be ready to reclaim by the end of a mine’s life.

Total Oil Sands Legacy Fluid Tailings

Alberta’s oil sands mining sector decreased total legacy fluid tailings by approximately 40 per cent between 2015 and 2024, according to the latest company reporting to the AER.

Total legacy fluid tailings in 2024 were approximately 623 million cubic metres, down from about one billion cubic metres in 2015.

The reductions are led by the sector’s longest-running projects: Suncor Energy’s Base Mine (opened in 1967), Syncrude’s Mildred Lake Mine (opened in 1978), and Syncrude’s Aurora North Mine (opened in 2001). All are now operated by Suncor Energy.

The Horizon Mine, operated by Canadian Natural Resources (opened in 2009) also reports a significant reduction in legacy fluid tailings.

The Muskeg River Mine (opened in 2002) and Jackpine Mine (opened in 2010) had modest changes in legacy fluid tailings over the period. Both are now operated by Canadian Natural Resources.

Imperial Oil’s Kearl Mine (opened in 2013) and Suncor Energy’s Fort Hills Mine (opened in 2018) have no reported legacy fluid tailings.

Suncor Energy Base Mine

Between 2015 and 2024, Suncor Energy’s Base Mine reduced legacy fluid tailings by approximately 98 per cent, from 293 million cubic metres to 6 million cubic metres.

Syncrude Mildred Lake Mine

Between 2015 and 2024, Syncrude’s Mildred Lake Mine reduced legacy fluid tailings by approximately 15 per cent, from 457 million cubic metres to 389 million cubic metres.

Syncrude Aurora North Mine

Between 2015 and 2024, Syncrude’s Aurora North Mine reduced legacy fluid tailings by approximately 25 per cent, from 102 million cubic metres to 77 million cubic metres.

Canadian Natural Resources Horizon Mine

Between 2015 and 2024, Canadian Natural Resources’ Horizon Mine reduced legacy fluid tailings by approximately 36 per cent, from 66 million cubic metres to 42 million cubic metres.

Total Oil Sands Fluid Tailings 

Reducing legacy fluid tailings has helped slow the overall growth of fluid tailings across the oil sands sector.

Without efforts to reduce legacy fluid tailings, the total oil sands fluid tailings footprint today would be approximately 1.6 billion cubic metres.

The current fluid tailings volume stands at approximately 1.2 billion cubic metres, up from roughly 1.1 billion in 2015.

The unaltered reproduction of this content is free of charge with attribution to the Canadian Energy Centre.

From Resource Works

A major shift is underway in Europe — and it’s a warning Canada would do well to heed.

Last week, the European Commission confirmed it plans to scrap its so-called “Green Claims Directive.” The proposal was designed to crack down on corporate greenwashing — companies making vague or misleading claims about how environmentally friendly their products are.

At first glance, that might sound like a worthy goal. Who wants false advertising? But the plan quickly ran into trouble, especially from smaller businesses who warned it would add layers of red tape, compliance costs, and legal risk.

In fact, the Commission itself admitted that as many as 30 million micro-enterprises could end up having to comply with the rules. Even with exemptions written in, the direction of negotiations pointed to increased burdens, not clarity. The result? A lot of businesses — even the well-intentioned ones — would stop talking about their environmental practices altogether, just to stay out of legal trouble.

Czech economist and tax expert Danuše Nerudová, a member of the European Parliament and a lead negotiator on the file, put it plainly: “I welcome the fact that the Commission has listened … and hope this opens the door to a more balanced and effective approach.” The proposal, she said, was “overly complex.”

If that sounds familiar, it should.

Canada’s own Bill C-59, which came into force this month, is already having a similar effect. The bill, which changes the Competition Act to target “greenwashing,” makes it legally risky for companies to say anything about their climate efforts unless they have airtight, independently verified proof — the kind often only available to large companies with big legal budgets.

At Resource Works, we’ve heard from organizations who’ve made the decision to stop communicating about environmental performance entirely. Not because they’ve done something wrong — but because the rules are vague, expensive to follow, and expose them to complaints even when acting in good faith.

That’s a loss. For consumers, for environmental progress, and for transparency.

Canada should be encouraging companies to communicate openly and credibly about their sustainability performance — not shutting down those conversations with threats of litigation. The European Commission has now acknowledged that its own approach, despite good intentions, risks backfiring. It’s time for Ottawa to take a similar step back.

With Prime Minister Mark Carney under pressure to unleash Canadian potential in the resource sector, revisiting Bill C-59 would be a sign of both good faith and practicality. Canada needs more innovation, more investment, and more real progress — not more reasons to say nothing.

It’s time to recycle Bill C-59 into something that actually supports good environmental practice instead of stifling it.