Expect ‘in-water construction’ near Giant Mine this summer

Some Giant Mine remediation project staff will spend July and August working in the water of Yellowknife Bay to help build a new treatment plant.

The area of “in-water construction” near the toxic former gold mine will be marked by lighted yellow buoys, the federally led project team announced on its website.

Remediation of the former gold mine, which is expected to cost more than $4 billion and take until at least 2038, officially began in 2021.

Work completed thus far has included deconstruction of the old roaster – once one of Canada’s most contaminated buildings – and the former townsite, as well as the creation of a non-hazardous waste landfill and closure of the mine’s underground.

The on-site water treatment plant is expected to be commissioned next year.

In a briefing for Yellowknife City Council this week, the Giant team said the treatment plant will allow staff to pump water directly from the underground through two wells, treat it and discharge it year-round.

Pumping water and treating it is designed to keep water at a safe level underground at Giant, well away from any toxic arsenic trioxide that was once buried as a byproduct of gold roasting.

A different form of water treatment at the site has already existed at the site for decades, one that involves storing water in a pool for lengthy periods before it is fully treated and then discharged. The new plant will skip the storage step, simply pumping, treating and discharging.

The Giant team has also issued notices related to summer work starting, some drilling work over the next two months, and what to expect regarding dust and air quality monitoring at the site this summer.