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Giant Mine provides update on remediation project
The project has been underway for several years, and is expected to last until 2038.
As the Giant Mine Remediation Project continues, the Crown-Indigenous Relations and Northern Affairs Canada (CIRNAC) group invited a number of media representatives to the mine site on Friday, November 7th, to provide an update on the progress they’ve made in decommissioning the mine, and what their next steps will be.
The mine first began official operations in 1948, and for more than fifty years, served as a strong economic driver for the City of Yellowknife, and the NWT. The Mine ended operations in 2004, leaving behind a troubled history of environmental contamination and an infamous explosion that took the lives of nine workers.
The main focus of the Giant Mine Remediation Project is to deal with a particular side effect of the mining efforts, that being the release of arsenic trioxide. Arsenic is a byproduct of the gold mining process, where the ore is heated to extremely high temperatures. The resulting gas can be very toxic, and in the early days of the mine’s operations, the arsenic gas was released directly into the environment of the Yellowknife area.
The Giant Mine Remediation Project addresses the long-term containment and management of the arsenic trioxide waste, the demolition and removal of all buildings on the surface, and the remediation of surface areas including the tailings ponds. It also includes water management and treatment options. (Connor Pitre/CKLB)
The goal of the Remediation Project is to minimize the health risks to onsite workers and the general public as much as possible, and it’s an effort that has been underway for several years already.
In their latest update, CIRNAC shared some of their most recently completed projects, those being the deconstruction of the former townsite, and the full closure of all underground areas.
Projects that are currently underway include the deconstruction of core buildings, the processing of contaminated soils, and as the largest current project, the construction of the new water treatment plant.
While the mine site already has a water treatment facility that is still in operation, this new facility will run at a higher quality. Much of the facility has already been completed, with commissioning activities expected to begin in Fall of 2026. The facility will come into full operation in 2027, and will remain in use throughout the remainder of the Remediation project.
The current water treatment plant still in use at Giant Mine (Connor Pitre/CKLB)
Patrick Schmidt, Project Lead for the Water Treatment Plant, explained why the new plant is needed in the first place.
“So because we have the arsenic rock size dopes that are underground, we need to keep the mine water elevation in the underground workings well below the arsenic. And so to do that, we have to constantly pump the water from the underground, and that water is contaminated. So we have to, therefore treat the water before it can be released. So that’s kind of the function of the water treatment plant. We started construction in 2023 so we’re wrapping up our third construction season on the water treatment plant, and we have about one more year to go.”
The Water Treatment plant is a crucial piece of the Remediation project. The contaminated water must be pumped up from underground chambers before it can be treated, and once it is properly cleaned, the water is gently released in Back Bay.
The interior of the new water treatment plant for Giant Mine, still under construction. (Connor Pitre/CKLB)
A pipe at Giant Mine that leads clean, treated water safely into Back Bay. (Connor Pitre/CKLB)
CIRNAC is in close communication with local Indigenous leaders throughout the process, with requests and concessions being followed closely. It was explained that the biggest request made by the YKDFN was that the land of the former mine site be left barren and “ugly,” in order to serve as a reminder of the environmental impacts suffered, and the lessons learned.
A representative of CIRNAC added that the group holds monthly working group meetings with all of the main local representatives, those being the YKDFN, North Slave Metis Alliance, City of Yellowknife, and Alternatives North.
“We worked really closely with them, and used a lot of their input to receive our water license and to create the design plans, to create our closure and reclamation plan. We also do quite a bit of outreach. We’ll be taking part in the spring trade show. We’ll be holding our annual public forum on March 11, and that will be an update on the work we’ve done in the past year, and the upcoming work on giant line for the years to come.”
The total area of the Giant Mine Remediation Project stretches farther than most would assume, even dipping into Alberta and the western reaches of Nunavut. As a result, contractors working with CIRNAC are working closely with Indigenous teams and leaders in their respective areas. Several indigenous governments are also involved in the project through high value funding agreements.
The total length of the Remediation project will continue for more than ten years, with the project expected to last until 2038.