Graduate Geotechnical Engineer Nilan Jayasiri is a PhD candidate at the University of Western Australia, helping drive the research methods for mine tailings management. His recent study, co-authored with Andy Fourie and Cristina Vulpe, investigates electroosmotic (EO) consolidation of fluid fine tailings, comparing constant voltage and constant current configurations. Presenting his findings at the 2024 Mine Closure Conference, Perth, Australia, here Nilan shares insights into his research, the challenges in tailings management, and the future of mine closure practices.
My interest began during my undergraduate studies, particularly in my final year project. Geotechnical engineering intrigued me due to its practical nature. After completing my master’s, I moved to Perth, where I noticed the prominence of mining and tailings management in Western Australia. I saw an opportunity to contribute to a field that addresses environmental sustainability and safety, and this led me to pursue a PhD on electroosmotic consolidation in tailings management.
Electroosmotic consolidation isn’t widely applied in the mining industry. Can you explain how it works and why it’s promising?
Absolutely. Electroosmotic consolidation, or EO, accelerates the dewatering of fine tailings, which are a waste product of mining. The method involves placing electrodes into the tailings and applying an electrical potential, causing water molecules to migrate toward the negatively charged electrode. This technique strengthens the tailings material by extracting water, which is essential for placing capping layers as part of mine closure.
Unlike conventional methods, EO can potentially offer more efficient and effective dewatering, which is critical in managing and rehabilitating tailings storage facilities.
What have been the key findings of your study on constant voltage versus constant current configurations?
Our study revealed distinct advantages for each approach. Under constant current, dewatering occurs at a higher, sustained rate, which enhances efficiency. However, this comes with a trade-off in higher power consumption. The constant voltage method, on the other hand, provides a steadier dewatering rate at the initial phase due to the high initial moisture and conductivity in tailings. However, in this approach, the dewatering rate tends to decrease as dewatering progresses. Each approach offers unique benefits, and the choice depends on specific operational needs and constraints.
How are industry stakeholders responding to your research?
Right now, we’re in the laboratory phase. While there’s definite interest, we’re still in the process of gathering data to demonstrate EO’s potential in a real-world setting. The idea is that as we refine our methods and results, the industry may start considering EO as a viable solution for large-scale tailings management.
Tailings management is an industry-wide challenge. How does your work align with the goals of sustainable mine closure?
Sustainable mine closure requires that the land be safely rehabilitated for future use, which includes effectively managing the large volumes of tailings left behind. The goal of my research is to make tailings stable enough to support capping layers, which isolate the material from the surrounding environment. By strengthening the material and reducing water content, EO could help meet regulatory standards and ensure that tailings facilities are left in a safe, sustainable state.
This year you presented your findings at conferences in Colorado and Perth. How are these opportunities shaping your research?
These conferences are exciting milestones. Presenting my research internationally allows me to get feedback from experts in the field and exchange ideas. The Colorado event is a bit broader, catering to a diverse audience, whereas the Perth conference will be more focused on mine closure. These events help me refine my approach, network with industry professionals, and hopefully open doors for future research collaborations.
Finally, where do you see your research heading?
There’s still a long way to go, but the current results are promising. I hope that as we continue refining EO techniques, we can see them tested in field trials. Eventually, I envision EO becoming a practical, industry-accepted method for managing tailings. It’s an exciting prospect to contribute to safer, more sustainable mining practices.
About
Nilan’s research is paving the way for innovative approaches in tailings management, with potential benefits for environmental sustainability and mine rehabilitation. As he continues to explore electroosmotic consolidation, his work represents an exciting step toward solving one of the mining industry’s most pressing challenges.
Nilan extends his sincere gratitude to his co-authors, Prof. Andy Fourie and Dr. Cristina Vulpe, and the University of Western Australia, whose expertise and support have been invaluable in driving this research forward.
Connect with Nilan at [email protected]