What's happening at Giant Mine? Summer/Fall 2024

In-water work complete

In July and August, the Project completed in-water work as part of the construction of the Water Treatment Plant. This involved removing a segment of an abandoned pipeline, installing a silt curtain around construction work to reduce sediment disturbance, placing gabion mats (rock-filled wire baskets), and installing the outfall pipe. This work was done in Back Bay, adjacent to the public boat launch using a barge, crane, small watercraft, and divers. The Project employed an in-water captain on a designated radio channel for boaters to manage traffic in the area.

With the in-water work completed, from now until 2028, the Project anticipates public access will remain minimally impacted with respect to the public boat launch and parking area, the Yellowknife Historical Society and Great Slave Sailing Club.

The Giant Mine Remediation Project's goal is to make sure public access to Great Slave Lake is interrupted as little as possible. Remediation or investigation activities may cause temporary and short duration disruptions to access. The Project will work to keep this as minimal as possible through to 2028.

For more information, you can visit our public boat launch area at the Giant Mine Site page, or see our safety notices and updates.

Underground paste-filling for the 2024 construction season

Underground paste-filling resumed on June 1st, 2024. This program's goal is to backfill near surface underground stopes to mitigate the risk of the ground sinking or sinkholes being created and improve the overall stability of the underground workings and freeze area.

The 2024 program is a continuation of last year's paste-filling operations, which were impacted by the wildfire evacuations, as well as the addition of voids that were planned for backfill this year. In total, it is anticipated that Nahanni, the subcontractor, will have placed approximately 75,000 m³ of cemented paste backfill in the underground in 2024.

This year's paste-filling program involves a new challenge: certain underground voids contain ice that has built up over many years. This ice needed to be thawed by pushing warm air into the mine prior to backfilling the affected areas. The Project completed paste-filling in October 2024. This marks the end of the Project's underground stabilization work and will allow the Project to shut down and permanently exit the underground mine.

Arsenic concerns amid wildfire seasons

The Giant Mine Remediation Project is aware of public concerns about the mobilization of arsenic from soils during active wildfires. The Project team has been informed of the research being conducted to look at the impacts and is sharing information with the researchers, but it is important to note that the Mackenzie Valley Environmental Impacts Review Board confirmed the scope of the Project remains within the site boundaries and that other parties are the lead when it comes to legacy impacts of arsenic.

As part of addressing legacy impacts, the Government of the Northwest Territories Department of Environment and Climate Change, in partnership with Crown-Indigenous Relations and Northern Affairs Canada's NWT Region Office, has conducted a human health risk assessment with respect to legacy arsenic. The Government of the Northwest Territories Department of Environment and Climate Change is funding research investigating the impacts of wildfire on arsenic mobility. Their department of Environment and Climate Change is best able to answer questions about how they are taking this research into consideration.

When it comes to the possibility of wildfire impacting the site, the Project team's first focus will remain the safety and health of staff, of the general public, and the environment. During a wildfire event, the greatest and most immediate risk is the fire itself. The Project team takes action to reduce the risk of area wildfire impacting the site. This has included collecting brush and clearing materials from recent construction and moving these away from structures and onto the tailings ponds (large areas of dry rock material) located within the core of the site. The Project team will continue to monitor and manage the risks on and to the site, considering all information, research, and expertise available to them, to keep the public and environment safe.

Giant Mine Oversight Board research status

Giant Mine Oversight Board is leading research for a permanent solution to manage arsenic trioxide stored underground at the Giant Mine site. The Board held a meeting in June 2024 to discuss some of the research to date. More information about the research program, including the different challenges any solution will need to address (PDF), can be found on the Giant Mine Oversight Board website.

Boaters' Meeting

The Project held a public meeting for boaters at the Yellowknife Historical Museum on June 11, 2024. During this meeting, the Project shared its plans for the in-water work that took place over the summer. This gave the team the opportunity to speak with the recreational boating community about how their access might see temporary delays while the work was taking place.

At the meeting, the Project also shared its plans for the new boat ramp to be constructed in the GSSC area. Concerns were raised expressed by Great Slave Sailing Club members about exclusive rights during active remediation in the area.. A Land Manager from the Government of the Northwest Territories attended the public meeting with intentions for further discussions between GSSC members and the GNWT.

For more information, you can visit Government of the Northwest Territories' Giant Mine Townsite and Boat Launch webpage, or you can email publicuse_giant_lieupublic@gov.nt.ca or call (867) 767-9236 ext 53190.

Working Group Site Tour

The Giant Mine Remediation Project Working Group met on June 13, 2024. The meeting ended with a tour of the site.

Highlights of the site tour include how much debris has been removed from site, updates on the Water Treatment Plant and a look at the Tailings Ponds and Polishing Pond.

Truth and Reconciliation Day Ceremony