How the Giant Mine remediation plan was developed
The Giant Mine Remediation Project's planning was guided by the Report of Environment Assessment, and the resulting Closure and Reclamation Plan that is now approved for implementation.
Notice
The remediation work at the Giant Mine site is beginning in summer 2021. The project expects to start the following activities:
- construction of a landfill to hold non-hazardous waste
- underground stabilization
- construction of the first of 4 freeze pads (includes rock blasting and other work to clear the area, as well as building an access road)
- ongoing operation and maintenance of the effluent treatment plant
- dust control
- waste management, including temporary hazardous waste storage
- metal recycling
- sewage and greywater management
- temporary road upgrades to facilitate hauling townsite debris to the landfill
Members of the public can expect to see increased traffic to the site, and some work may be visible from the Ingraham Trail. Blasting activities are expected in the fall 2021. As per safety regulations, the Main Construction Manager will ensure appropriate notification prior to this work. While this work is ongoing, the project team will also ensure regular care and maintenance activities take place to keep people and the environment protected as the remediation moves forward.
The project team reminds the public that the Giant Mine, including the townsite north of the marina, is a contaminated site. Workers receive training and wear special equipment to protect them from hazards. For the public, access is not allowed because of health and safety risks. When near the site, please respect property boundaries and warning signs. When driving the Ingraham Trail, stay on the roadway or dedicated pull-outs.
For more information, email aadnc.giantmine.aandc@canada.ca.
What is the status of the site and the remediation plan?
The Giant Mine site has received the regulatory approvals to proceed in implementing the Closure and Reclamation plan. Work begins in the summer of 2021, and is expected to take 10 years to complete.
While the project team worked toward regulatory approvals for the cleanup, the site was under care and maintenance to manage ongoing risks. It was home to more than 50 years of gold mining and ore processing. Arsenic trioxide stored underground requires effective management to protect human health and safety and the environment. The closure and reclamation plan outlines how this will be done and describes general site clean-up activities on both the surface and underground of the mine site. The plan was approved by the Mackenzie Valley Land and Water Board as part of the water licence and land use permit regulatory process that began in April 2019. Care and maintenance activities will also continue on the site throughout remediation.
For more information, you can call the project office at (867) 669-2426 or email aadnc.giantmine.aandc@canada.ca.
What does the remediation plan for the site include?
The Giant Mine Remediation Project's Closure and Reclamation plan is the blueprint for cleaning-up the site to ensure human health and safety and to protect the environment. It covers the clean-up of the entire mine site, both surface and underground areas. The initial plan received thorough review by technical advisors and subject matter experts to ensure it addresses all the issues associated with cleaning-up the mine site. The updated plan also underwent thorough review and public engagement. The final plan includes consideration of potential future uses of the site (after the remediation is complete), but the Government of the Northwest Territories and the City of Yellowknife will make the final decisions on any future land uses.
The closure and reclamation plan for the site addresses:
- containing and managing arsenic trioxide waste over the long-term
- demolishing and removing all buildings and debris areas on the surface
- remediating surface areas including Baker Creek, the tailings ponds, open pits and contaminated soil and waste rock
- water management and treatment
- filling and covering pits
- remediating the townsite and nearby shoreline sediments
The goal of the remediation is to minimize public health and safety issues, as well as environmental concerns. The project team will work to return the site as closely as possible to the natural landscape for the Yellowknife area. Some areas will remain under active management and monitoring. New and relevant information regarding this project will also continue to be considered and evaluated.
Will the final remediation be safe?
The long-term remediation of Giant Mine will comply with all applicable legislation. The Closure and Reclamation plan includes cleanup methods successfully used at other contaminated sites across North America and the world. The project team will adopt safety measures used during other complex and challenging projects in North America. In addition, managing the arsenic trioxide dust in place (where it is currently stored) will avoid the health risks to workers who would have had to move the toxic material if the plan included taking it out.
The Government of Canada has spent nearly 20 years assessing Giant Mine to gather the necessary information to develop the Closure and Reclamation plan. The plan for the long-term management of the underground arsenic trioxide dust was presented to the public and discussed at 2 separate workshops in 2003. The Giant Mine Oversight Board leads the ongoing research for a more permanent solution.
Options for the surface remediation were presented to the public through the Surface Design Engagement process in 2015 and 2016. Input received from the public was incorporated into the approved Giant Mine Closure and Reclamation Plan The project team will continue to engage with the public as the remediation moves forward.