Managing Tailings

Corporate Responsibility

Managing Tailings

The continuous improvement of tailings management is an integral component of successful oil sands mining operations. Reducing the size and need for tailings ponds, and increasing the speed with which they can be reclaimed, are ongoing challenges being addressed by the industry. 

Canadian Natural has taken significant steps to minimize the footprint of tailings. Our comprehensive land use planning considers the end of mine life so that we can manage our environmental closure programs and obligations, and advance reclamation as quickly as possible.

Canadian Natural has invested almost $3.8 billion in tailings research, technologies and project construction. Our tailings management technologies are the result of extensive research that can be applied on a commercial scale. This work exemplifies our approach to R&D, taking lab concepts through the pilot stage and on to commercialization. 

 What are Tailings?

Tailings are a mixture of water, sand and clay found naturally in oil sands that remain following the mining extraction process. Tailings are transported by pipeline and deposited into ponds, where the majority of the solids – mostly sand – settle to the bottom. The remaining fluid (water and clay) is called Fluid Tailings (FT). As the solids in the FT begin to settle, the FT densifies, turning into a mixture called Mature Fine Tailings (MFT). Some of the MFT remain in tailings ponds, trapping water and reducing the amount of water available for recycling. Find out more about oil sands tailings from start to finish in this video.

Advancing tailings management technologies

Our tailings management strategies align with regulatory requirements based on two key principles: 1) creating landforms that fit within the local landscape, and 2) supporting productive wetlands and boreal forest habitats. Our processes focus on preventing FT through optimizations and continuous improvements.

Our technologies are increasing water recycling and improving tailings consolidation over time, to ultimately accelerate the reclamation process. They are also reducing GHG emissions.

  • At Horizon, we use a Non-Segregating Tailings (NST) process and CO2 injection. NST are tailings that have been significantly treated (dewatered) to form a homogeneous, semi-cohesive mass when deposited. The NST process dewaters the tailings by using cyclones to separate the coarse sand and thickeners to capture fines and remove water in the tailings stream prior to being sent to the tailings pond. The warm water that is removed and recovered is then re-used in our bitumen extraction process. The coarse sand and thickener underflow are then mixed and further combined with CO2 from Horizon’s capture plant, which further enhances fines capture and accelerates.
  • At Albian, we use thickeners and centrifugation technologies to help separate and remove water from the FT. In addition, an Atmospheric Fines Drying (AFD) technology at the Jackpine mine helps settle out solids in the FT, and we have composite tailings at the Muskeg River Mine. 

We are also optimizing and sharing knowledge and technologies between the Horizon and Albian operations, as well as with industry through COSIA with the goal of increasing operational efficiency.

Technology pilots

Horizon and Albian’s fines capture performance continues to be above conventional tailings capture. Horizon’s NST process captures tailings fines, decreasing fines going to the tailings pond and forming FT. The FT plant was commissioned in the summer of 2019 to combine NST with legacy FT and enhance the fines capture process, increasing the amount of fines captured and further reducing fluid fines generation from the outset.

A field pilot is underway on an alternative bitumen extraction method at Horizon — the In-Pit Extraction Process (IPEP). This involves a relocatable, modular extraction plant that processes ore and separates bitumen right in the mine pit. IPEP reduces materials transportation by truck, pipeline length and the energy needed to pump material, potentially reducing GHG emissions by up to 40% compared to typical oil sands processing plants. This process also produces stackable dry tailings, eliminating tailings ponds. Learn more about IPEP by watching this video.

We are also working with Titanium Corporation to evaluate the potential deployment of their froth treatment tailings remediation technology to recover bitumen, solvents and minerals from the tailings stream. This technology can provide cleaner/dryer tailings, reduce and avoid fugitive emissions from the tailings pond and produce new products such as zircon and titanium.

At Albian, several technologies were piloted, including filter bags to dewater tailings, and improved (centrifuge optimization trials for long-term consolidation of treated fines and enhancements to the AFD). In 2019, we tested a filter press technology that uses a mechanical filter to press FT, producing water for recycling and dewatered solids suitable for reclamation material in only a few hours.

Canadian Natural is also investigating tailings revegetation, such as the effects of NST on plants growth during reclamation. Along with other oil sands operators, we are also researching the viability of pit lakes for treating process-affected water and sequestering tailings, as part of oil sands mine closure plans. 

For more information on our technology projects, read our Technology and Innovation Case Studies booklet

Cyclones in the Horizon NST plant

Community involvement in tailings planning

Throughout tailings research, planning and execution efforts, Canadian Natural has regularly engaged with stakeholders, in particular neighbouring communities, and we will continue to do so. Building on the foundation of our tailings management plan and our research, we strive to optimize resource recovery and reclaim the landscape.

Applied Process Innovation Centre (APIC) - The future of tailings

R&D testing and technology improvements requires access to authentic samples, high quality industrial equipment and knowledgeable personnel familiar with mining operations. With ongoing research being a critical piece of our tailings management strategy, Canadian Natural built and commissioned the Applied Process Innovation Centre (APIC) at Horizon. 

The 3,600-square-foot APIC was designed and equipped to perform a variety of tests and programs to investigate and accelerate the application of promising tailings technologies to a commercial scale, including thickened tailings production, NST, CO2 sequestration testing and MFT treatment. It also acts as a collaboration hub so industry peers members can complete tailings research with samples from their own operations directly and through COSIA, academia and government. 

CO2 Capture and Injection into tailings

Horizon’s CO2 recovery plant has a capture capacity of 438,000 tonnes of CO2 annually – the equivalent of removing the emissions of 92,000 passenger vehicles from the road. Horizon’s CO2 capture plant is part of our hydrogen plant, which produces 144 million standard cubic feet per day of hydrogen that is used in secondary upgrading to stabilize the synthetic crude oil and reduce impurities. 

The CO2 is added into the tailings stream before it enters the pond, where it creates a chemical reaction that changes the tailings water pH to be the same as river water. This reaction allows the solids (fines) to settle more quickly and for the quick release of clear and warm process water for recycling. 

Left: Current tailings pond with CO2 added. Middle: Without the addition of CO2 the footprint of our tailings pond would be almost double the size. Right: Horizon CO2 recovery complex.