Giant Mine Reclamation Project

Summary

The Giant Mine Remediation Project in Yellowknife, Northwest Territories, is focused on addressing environmental contamination from an abandoned gold mine that operated from 1948 to 2004. The project involves the stabilization of arsenic trioxide waste stored underground and the remediation of open pits and tailings ponds. The government of Canada has taken responsibility for managing the mine's environmental legacy, including water levels affected by local conditions. The project aims to ensure long-term containment of hazardous waste and mitigate risks to the surrounding community.

Takeaways

• 😀 The Giant Mine reclamation project is located on Chief Dry Geese territory, historically the land of the Yellowknives Dene First Nation and more recently the North Slave Metis Alliance.
• 😀 The mine operated from 1948 to 2004, leaving behind significant environmental contamination, including arsenic trioxide waste stored underground.
• 😀 After the Giant Mine owner went into receivership, the Government of Canada took responsibility for the environmental liabilities at the site.
• 😀 The site includes an underground mine, eight open pits, 35 mine openings, four tailings ponds, and widespread arsenic contamination in the soil.
• 😀 The remediation project aims to stabilize the mine site and manage the long-term containment of arsenic trioxide waste.
• 😀 There is community concern regarding the storage of arsenic trioxide waste in underground chambers, some of which will be frozen to prevent contamination.
• 😀 The mine's underground water, known as the mine pool, is affected by local weather, with water levels rising and falling by 10 to 20 meters annually.
• 😀 In extreme cases, the water may rise by as much as 50 meters, but this only occurs occasionally over the next 15 years.
• 😀 Critical infrastructure will not be impacted by rising water levels during the remediation process.
• 😀 Long-term remediation efforts, including the management of open pits and tailing ponds, will result in less water to manage in the underground mine, with water levels fluctuating by only approximately 10 meters annually.

Q & A

What is the Giant Mine, and where is it located?

The Giant Mine is an abandoned gold mine located in Yellowknife, Northwest Territories, Canada. It operated from 1948 until 2004 and has left behind environmental contamination, including arsenic trioxide waste stored underground.

Which Indigenous peoples' territories does the Giant Mine sit on?

The Giant Mine is situated on the traditional territory of the Yellowknives Dene First Nation, and more recently, the homeland of the North Slave Métis Alliance.

What is the main environmental issue at the Giant Mine site?

The primary environmental issue at the Giant Mine is the arsenic trioxide waste stored underground in purpose-built chambers. This waste is highly toxic and poses long-term environmental and health risks.

What steps are being taken to remediate the Giant Mine site?

The Giant Mine Remediation Project aims to stabilize the mine site, manage arsenic trioxide waste, and address the long-term containment. Some of the mined-out areas have been backfilled with cemented mud, and other areas containing arsenic waste will be frozen to prevent contamination from escaping.

Why is there concern about storing arsenic waste underground?

There is concern because the arsenic trioxide waste is stored underground, and any instability or failure of the containment systems could lead to contamination escaping into the surrounding environment, posing risks to health and the ecosystem.

What is the role of freezing in managing the arsenic trioxide waste?

Freezing is used to stabilize areas containing arsenic trioxide waste. By freezing these areas, the waste is kept contained and prevented from contaminating the surrounding environment.

What is the 'mine pool,' and why is it important in the remediation process?

The mine pool refers to the water that accumulates at the bottom of the mine, which is affected by local weather and groundwater flow. The water levels in the mine pool fluctuate annually, but it is important to note that critical infrastructure is not impacted by these fluctuations during the remediation process.

How do weather conditions affect the water levels in the mine pool?

Water levels in the mine pool rise and fall due to local weather conditions. On average, they fluctuate by 10 to 20 meters annually, and in rare cases, they may rise as much as 50 meters, but this does not affect the critical infrastructure.

What will happen to the mine pool once the open pits and tailing ponds are remediated?

Once the open pits and tailing ponds are remediated, there will be less water to manage in the underground mine. Water levels will continue to rise and fall with weather conditions, but the fluctuations will be more controlled and limited to about 10 meters annually.

How long will the remediation of the Giant Mine site take?

The remediation of the Giant Mine is a long-term project, with the process of managing and stabilizing the site, including controlling the water levels and arsenic waste, extending over 15 years.