Gone are the days when a mining company could come in, set up shop, mine the ore, and perform land rehabilitation afterward. Now, companies must compensate and care for the surrounding land, air and water during the operational life of a mine, according to JoAnne Mooney, environment, health and safety supervisor of Agrium Kapuskasing Phosphate Mining Operations.
In fact, accountability is becoming more common place since the requirement of a certified closure plan (part seven of the Mining Act) was proclaimed in 1991.
Situated 40 kilometres southwest of Kapuskasing, the company is in its fourth year of relocating Cargill Lake about 300 metres south.
It has been a long process, but Mooney says it has gone well and by summer’s end, the transfer of all acquatic life and habitat will be complete to allow for the expansion of the open-pit mine.
Agrium’s mine life is projected until 2020, at which time the pit itself will replace the old Cargill Lake.
The company has worked closely with engineering consultant Rob Whyte from Calder Engineering Ltd. out of Bolton, and fisheries’ biologist Cynthia Russel from Minnow Environmental Inc. to ensure the success of all aspects of fish life stages.
Although lakes in other areas have been moved in the mining industry, there is no “how-to” manual for relocation. Consequently, extensive care and consideration was taken in the preparation of a report for the Ministries of Environment, Natural Resources, Northern Development and Mines, the federal Department of Fisheries and Oceans, and local First Nations.
With a common-sense approach, Mooney says they anticipated ministry questions.
“We put a lot of work in the front end by addressing problems ahead of time,” says Mooney.
“Anything that could be impacted by the project was considered.”
The company held a series of community information sessions occurred as well as a tour of the lake to familiarize people with the project.
The 25-hectare lake spans 400 by 300 metres with an average depth of three metres. There are approximately 500 fish in it, consisting primarily of pike and yellow perch.
Last year, the first construction phase involved constructing the new lake itself, removing organics (trees, bush, topsoil, etc.) and creating marginal areas. A natural depression in the topography assisted in the design for the new lake. Three water cells (ditches along the shoreline) were established where vegetation was transplanted to help establish the shoreline.
As well, a fish ladder was constructed, similar in nature to an underwater flight of stairs, connecting the lake to the downstream creek.
Fish habitat was built into the basin, ensuring their reproductive cycles would not be interrupted by the industrial operation.
The new lake is now close to full due to seasonal runoff and rainfall. In addition, Agrium is pumping water from Cargill Lake to the new lake, in order to restore the water in Cargill to its original levels, which were readjusted with government approvals to accommodate the mining operation.
Starting May 1, crews will troll along the shoreline, transplanting microscopic aquatic life and forage fish, such as minnows. Once they are assured the forage fish have survived to provide a food base for the larger fish, and the three-month spawning period is completed, the fish will be moved to the new lake in stages around late August. By gradually lowering water levels, more crews will net or electroshock (temporarily stun) the fish and carefully place them in the new lake for the duration of the mining operation.
Building a better lake?
The new lake will take advantage of technology to keep the lives of the existing wildlife as normal as possible. It will have a higher flushing rate, resulting in more dissolved oxygen, which is generally low in the northeastern Ontario lakes, says Mooney. She added that old Cargill Lake tended to be an isolated lake due to a seasonal outflow of the downstream creek, allowing little fish movement. The fish ladder will allow greater movement of the fish between the downstream environment and the new lake.
She also pointed out that despite the changes, there are no anticipated impacts in water quality or quantity to the downstream environment. The lake is monitored continuously.
On the lighter side, Mooney put out an invitation to Agrium staff members to name the new lake. As of April 18, the new lake’s name is Lake Pitama, one of several dialects in Cree meaning “for now.”
