Research paper wins Thomas C. Keefer Medal after 10 years in the making

Craig Nichol

It has been a long road for UBC researcher Craig Nichol to help devise a green solution to mitigate landscape contamination from mine tailings. A joint research paper on the subject, which for various reasons took more than a decade to complete, has won top national honours.

Nichol, an assistant professor in earth and environmental sciences in the Irving K. Barber School of Arts and Sciences at UBC’s Okanagan campus, and three co-authors were recently awarded the 2014 Thomas C. Keefer Medal for the Best Paper of 2013 in hydrotechnical, transportation, or environmental engineering by the Canadian Society of Civil Engineers.

The award-winning paper examines the type and amount of materials used to cover mine tailings and how they may prevent contamination, or ‘acid rock drainage’ from the tailings.

The project began in 2000 with researchers Bonnie Dobchuk, G. Ward Wilson, and Michel Aubertin.  Nichol took over the work in 2003 while working with Wilson, who then held the ChairofMining and the Environmentat the Norman B. Keevil Institute of MiningEngineering at UBC. First drafts were completed in 2004, but busy schedules kept the study on hold. The research took place at the Detour Lake Mine, a gold find in northeastern Ontario. When the mine re-opened in 2012, the authors recognized the story needed to be told, and Nichol took the lead in getting the paper published.

Titled The Evaluation of a Single-layer Desulphurized Tailings Cover, it was published in the Canadian Geotechnical Journal in May 2013. The research examines how materials from the mining process can be used to cover mine tailings—with the goal of preventing the tailings from oxidizing and leaching  into ground water sources. This process, termed, ‘acid rock drainage’ — when water containing concentrations of acid and metals leaches from mine wastes—has become an environmental concern.

Dealing with mining tailings in a safe manner has proven to be an expensive process for mine operators and Nichol explains that before a mine closes, there must be plans in place for mine wastes to be covered, with the goal of re-establishing vegetation.

“Preventing acid rock drainage, or other harmful materials, leaching from mine wastes represents a large cost for current mines,” Nichol says. “The cost of remediating historical mines with no current owners represents a large liability to the Canadian taxpayer.”

At the Detour Lake Mine, desulphurized tailings were used to cover reactive tailings, which reduces cost of ground cover construction in areas where natural soils are not available, says Nichol. The paper details how this works. Essentially, the new ground cover creates an oxygen diffusion barrier to prevent generation of acid rock drainage from the underlying mine tailings.

“The modelling work allowed us to make recommendations of potential new methods for designing these covers to maximize their efficiency,” says Nichol. “This is particularly important for areas with limited natural soils that could be used as a cover material.”

Nichol says as the Detour Lake Mine has re-opened, researchers now have the opportunity to study the performance of the cover during the past 10 years to see how it compares to the modelled predictions.

“This should improve our ability to design covers at other mines,” he adds.