In 2022, cement production accounted for eight per cent of the world’s total carbon emissions, releasing 1.6 billion tonnes of carbon dioxide into the atmosphere. As climate change worsens, reducing carbon emissions becomes more necessary than ever. As such, many researchers are seeking alternative methods to produce cement-like materials without the expensive carbon cost.
Fatemeh Tavanaei, a PhD candidate at McGill’s Department of Mining and Material Engineering, recently published a study in the journal Applied Thermal Engineering focusing on alleviating carbon emissions in the mining industry by developing a “frozen zero-cement backfill.” This novel method aims to replace traditional cement with an environmentally-friendly solution, helping make mining operations more sustainable.
Tavanaei’s approach involves using ice sourced from the Arctic region to create a new material mixed with mine tailings—the leftover waste from mining activities. This material provides the necessary structural stability for backfilling, a process where excavated areas are refilled to prevent the collapse of tunnels or shafts.
“The objective is to explore the feasibility of using frozen water from the region to create a new mixture with mine tailings, which would be environmentally compatible and minimize disruption to the ecosystem,” Tavanaei wrote to The Tribune. “By taking advantage of the natural freezing conditions, this approach eliminates the need for cement, thereby preserving the integrity of the surrounding environment and reducing the carbon footprint of mining activities.”
Tavanaei’s research team conducted a case study for this material in Nunavut’s Chidliak diamond mine, which can only be accessed by air or by trail. Located in the Hall Peninsula of Baffin Island, the area is surrounded by continuous permafrost extending several hundred metres into the ground.
Since transporting material to such a remote location is difficult, Tavanaei’s group tried to minimize the logistical challenges by using the natural Arctic environment in their favour.
“The water required for the frozen zero-cement backfill is readily available in the area. Furthermore, the water used [primarily comes] from the wastewater produced by the processing plant,” Tavanaei wrote. “This approach not only reduces the need for additional water but also contributes to effective wastewater management, making it an environmentally responsible solution.”
Tavanaei and her team are also working to ensure that the frozen zero-cement backfill remains durable long-term, making sure it can withstand changing conditions including climate change effects. Although further research will be needed to fully understand its long-term impacts, Tavanaei is optimistic about its potential.
“While the method is still relatively novel, we have carefully planned for its long-term viability,” Tavanaei wrote. “Our research team is committed to ensuring that the frozen zero-cement backfill can be used effectively and sustainably over extended periods.”
Tavanaei is also hopeful that this backfill method can be adapted to other parts of the world with similarly cold climates. She emphasized the need for careful evaluation to determine if it can be cost-effective and environmentally sound in other regions.
“Each case requires an extensive feasibility study to ensure cost-effectiveness and assess potential environmental impacts,” Tavanaei wrote. “Artificial freezing is already used in ground stabilization techniques, and our research group has been involved in developing and optimizing such methods.”
Although frozen zero-cement backfill is still in its early stages, Tavanaei envisions it as a promising solution for a more environmentally conscious future.
“Sometimes, nature provides us with solutions that we may not fully appreciate until we take the time to observe and understand them,” Tavanaei said. “We believe that by closely studying natural processes, we can uncover innovative and sustainable approaches to mining and environmental preservation.”