A Breakthrough in the Recirculation of Mine Water
09 février 2022
In 2019 and 2020, CRI reduced the volume of fresh water drawn from Bombardier Lake by more than 50%. More specifically, whereas 764,629 m3 of water was drawn in 2018, this volume dropped to 314,831 m3 and 338,292 m3 in 2019 and 2020.
This reduction in use can mainly be attributed to the acquisition and start-up of a nanofiltration water treatment unit, which makes it possible to reuse a greater proportion of process water, thus reducing the intake of fresh lake water. Another benefit is the decreased generation of contaminated water that must be stored in the tailing facility.
To accomplish this, the water from the tailing facility is sent back to the concentrator and is filtered through membranes with very small pores, which allows for its reuse in the ore concentration process. Nanofiltration removes contaminants 50,000 times smaller than a hair. It is an advanced water treatment technology.
Considerable logistical efforts went into its installation and optimization. First, it involved installing an actual little water treatment plant inside an already existing plant. And secondly because the process that helps transform copper and nickel ore into a concentrate is very sensitive to water quality variations, great care had to be taken to fi ne-tune the operating parameters, and staff had to be trained to ensure that the treatment unit ran properly.
So, whereas it took approximately 0.40 m3 of fresh water (400 L) to process a ton of ore in 2018, today it takes approximately 0.12 m3 (120 L).
CRI will continue its efforts in the area of sound water use management in the years to come in order to reduce its environmental impact in Nunavik as much as possible.