A researcher from the University of Waterloo has determined that the multi-layer covers used to remediate abandoned mine sites have lived up to their expectations, even after 50 years.

Old, abandoned mine sites across Canada are commonly remediated with a multi-layer cover of soil, gravel, and sand so they don’t release toxic substances into the environment. Aria Zhang wanted to know if they have been serving their purpose.

Zhang had two concerns regarding the success of the covers. First, she wondered if they break down over time, releasing the toxins back into the environment. She found that although one of the sites she checked had some small holes and fractures, the majority of the covers held up over the last half-decade.

“We did find one spot out of the three random spots that we selected that there are some small fractures, but it is pretty local and small,” she stated.

Secondly, she wondered if the laying of the covers creates a disturbance, also freeing toxic metals such as lead and arsenic.
“We were able to find that the cover did not disturb the sedentary faces, so it did not cause additional release of the heavy toxic metals.”

The mines she tested were abandoned in 1972 near Timmins, Ontario. Zhang says she used to Canadian Light Source at the University of Saskatchewan to determine her results. Overall, Zhang concludes that these multi-layer covers do their part to protect the air, water, and soil that surrounds them, making for a healthier environment.