The Yukon Supreme Court has approved a plan to clean up the abandoned Mount Nansen mine site, one of seven large, contaminated mine sites in the Yukon.
The plan is to find a company that will buy the mine site and move all of the tailings and contaminated soil from the site into the mine’s open pit, which would then be sealed.
The federal government will pay for the remediation work, which is supposed to be completed within 10 years.
The Mount Nansen site is located 60 kilometres west of Carmacks, on the traditional territory of the Little Salmon/Carmacks First Nation. The mine was operated by BYG Natural Resources between 1996 and 1999, when the company abandoned the property.
Since devolution in 2003, the Yukon government has been responsible for managing the care and maintenance of the site, while the federal government has paid for the work.
There are currently about 300,000 cubic metres of tailings, 500,000 cubic metres of waste rock and 55,000 cubic metres of contaminated soil left at the site, along with buildings and other infrastructure that must be demolished.
The remediation plan, designed by engineering company AMEC Foster Wheeler, involves pumping water from the open pit and building a platform out of waste rock in the pit to hold all the contaminated material above the groundwater level. The tailings and contaminated soil would be emptied into the pit, which would be continuously lined with waste rock as it filled up, and then covered.
The buildings and concrete foundations on the site would be demolished, and the valley would be restored.
Water discharge from the pit would be monitored “until such discharge has ceased,” according to a report from the site’s court-appointed receiver.
The plan has been approved by the federal and territorial governments and by the Little Salmon/Carmacks First Nation.
Parties interested in purchasing the mine site and completing the remediation work will have 60 days to respond to a request for qualifications from the receiver, PricewaterhouseCoopers.
Shortlisted proponents will then have about nine months to develop full proposals. The receiver hopes to notify the successful purchaser by June 2017, and to close the deal by the end of that year.
Proponents will be evaluated based on their expertise, their financial status, and their presence in the Yukon and commitment to providing benefits to the Little Salmon/Carmacks First Nation.
The remediation plan has been divided into 17 tasks, ranging from preparing a proposal for the Yukon Environmental and Socio-economic Assessment Board, to excavating the waste rock and tailings and moving them into the open pit, to monitoring the site after the remediation is complete.
The purchaser will have to provide individual cost estimates for each task. Most of the tasks are to be completed within 10 years.
The Mount Nansen site is one of four abandoned mine sites in the Yukon for which federal and territorial governments are responsible. The others are the Faro, Keno Hill and Clinton Creek mine sites.
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