Yellowknife | Cleaning up the old gold mine is estimated to cost taxpayers 4.38 billion

The Treasury Board of Canada recently approved a new $4.38 billion cost estimate for the rehabilitation of the Giant Mine, a former gold mine that operated from 1948 to 2004 within the city limits of Yellowknife.

The cost of the federally-led project was estimated to be less than $1 billion in 2013, but that does not take into account inflation, contingencies and project management costs, as well as expanded remediation plans.

Natalie Plato, assistant director of the Giant Mine Remediation Project, said she was aware of her rights and listened to stakeholders. “We think this is a very positive initiative for Yellowknife and the surrounding area,” she said.

Kevin O’Reilly, a member of the Northwest Territories legislature who is a stakeholder in the Giant Mine cleanup plan as an environmentalist, said he was not surprised by the new award.

“It’s certainly a huge amount, but it won’t surprise anyone,” he said. Travel expenses for getting contractors and others have skyrocketed recently. »

Mr O’Reilly said he would like to see a breakdown of the cost estimate. He said he had to insist on knowing the earlier estimate, and ultimately get the amount by filing a Freedom of Information request.

The $4.38 billion cost estimate includes all remediation project costs since 2005 and projected future costs during ongoing operations.

The remediation process was originally supposed to be completed in 2031, but that deadline has been pushed back to 2038. However, some aspects of the project require maintenance, such as the 237,000 tonnes of highly toxic arsenic trioxide dust stored underground at the site. and permanent maintenance.

Ongoing operating costs are likely to be significant, O’Reilly said.

Since the release of the initial cost estimate, the project has gone through the water permitting process and environmental assessment, resulting in 26 statutory measures to be completed before the project is completed. A solution can be undertaken.

Other changes include a monitoring board to measure levels of arsenic and other contaminants in Yellowknife, N’Dilo and Detta residents through biological sampling, community benefit and cooperative agreements, and a health effects monitoring program.

M^me Another change requested by stakeholders is to bury eight open pits on the site rather than leaving them open to protect the ground from flooding.

The scale of the mine cleanup is enormous, with the site spread over 900 hectares. It contains 13.5 tonnes of contaminated soil, a landfill, six settling ponds and 100 buildings, including an abandoned housing estate with asbestos in former workers’ homes.

Over the next decade, remedial work will include construction of a new water treatment plant, reconstruction of an old housing estate, underground stabilization using cement mix, tailings and chemical additives, and freezing of underground arsenic chambers using 858 thermosyphons. Long tubes filled with carbon dioxide under pressure.

This dispatch is produced with financial support from MetaExchanges for News and The Canadian Press.