Constructed wetlands remove heavy metals from mine water
Scientists at the Yukon Research Centre have proven that heavy metals can be removed from contaminated mine water with northern constructed wetlands. These results offer a sustainable and cost effective option for mining companies operating in the North. This research was funded by the Natural Science and Engineering Research Council of Canada (NSERC) and Casino Mining Corporation (Casino).
Eight laboratory-scale wetlands were constructed in partnership with Casino to determine whether this passive water treatment system is feasible in a northern climate. Researchers took a multi-disciplinary approach by combining the expertise of soil scientist and plant ecologist, Dr. Katherine Stewart, and aquatic biochemist, Dr. Amelie Janin. The wetlands were able to remove 96% of cadmium, 99% of copper, 79% of selenium, and 97% of zinc concentrations from simulated mine water.
“These results provide mining companies and permitting agencies with more information and more options from an independent research body”, said Dr. Amelie Janin, NSERC Industrial Research Chair in Mine Life Cycle, Yukon College. “Our research is increasingly being used by companies in the mine permitting process and that is exactly what we hope to achieve, to solve northern problems through applied research,” said Janin.
While constructed wetlands are used in southern Canada for metal contaminated water, further research is required to understand the metal removal mechanisms in cold climates with short growing seasons. Not only did the wetlands remove high levels of heavy metals from water, but findings suggest that metals didn’t accumulate in the plants, but are retained in the wetland sediments, therefore reducing the risk of contaminating foraging wildlife, and offering a stable disposal mechanism for the heavy metals.
“This project represents Casino’s commitment to sustainability, using research and innovation to capitalize on natural processes, including native plant species, to be used in the long-term closure solution of the proposed Casino mine” said Paul West-Sells, President of Casino.
Casino is a new addition to the Yukon Mining Research Committee that is led by Dr. Janin at the Yukon Research Centre. The committee originally began with Alexco Resource Corp., Capstone Mining Corporation, Yukon Zinc, and Victoria Gold Corp. and has recently expanded to include Casino and Selwyn Chihong Mining Ltd. The committee is a sub-committee of the Centre for Northern Innovation in Mining's governing council.
This committee aims to develop research leadership in addressing northern challenges and opportunities within Yukon’s mining industry, according to the recently completed strategic plan.
“Our scientists are here to solve northern problems with northern expertise through research and innovation”, said Dr. Chris Hawkins, Vice President Research and Community Engagement, Yukon College. “Our strength lies in our ability to partner with industry, government, First Nations, and communities to improve the lives of northerners”, said Hawkins.
For more information on this project, and to see the final report, please visit our website or www.casinomining.com.