Environment

De Beers one step closer to closing former Snap Lake mine


The NWT government has approved a key step in De Beers Canada’s plan to clean up and close down the site of its Snap Lake diamond mine, where work ended in 2015.

Shane Thompson, the territorial minister of Environment and Natural Resources, approved De Beers’ application to renew the mine’s water licence on May 21.

The 15-year water licence, which will be in effect until 2035, covers activities designed to safely close down Snap Lake. The Mackenzie Valley Land and Water Board, which is the regulator overseeing Snap Lake, had recommended Thompson approve the application.

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The licence allows for the construction, operation, and maintenance of facilities and roads at the mine site, as well as fuel storage and quarrying. De Beers can withdraw up to 188,000 cubic metres of water from Snap Lake itself every year. 

The licence comes with a number of conditions, including compliance with a monitoring program, water waste criteria, and submission of annual reports.

De Beers will also have to submit revised waste management, spill contingency, and final closure and reclamation plans.

That means the closure plan must go through another round of updates and public review later this year before De Beers can move forward.  

De Beers must also provide a $31,194,253 security deposit.

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Two-phase closure

In its March 2019 final closure and reclamation plan, De Beers said it intended to close the mine in two phases.

The first phase, spanning eight years, includes decommissioning mine facilities, adapting water management systems, and reshaping and revegetating land. The second post-closure phase is expected to continue for a maximum of 10 years and focuses on monitoring programs. 

Granting of the licence was first reported by the CBC.

De Beers said its overall goal is to return the site and surrounding areas to “self-sustaining ecosystems that are compatible with a healthy environment and with human activities.” 

That means maintaining dust levels and water quality that are safe for people, vegetation, and wildlife, and making sure the shape of the landscape and vegetation matches the natural environment. 

According to De Beers, construction of the mine has disturbed about 1.88 square kilometres of vegetation. 

There are seven species of fish in Snap Lake, while the area around the mine is home to caribou, grizzly bears, wolverines, wolves, foxes, and birds. The landscape features spruce, willow, and birch trees as well as a number of shrubs, lichens, and mosses. 

Waste pile to be covered, smoothed

The Snap Lake underground diamond mine, located about 220 km northeast of Yellowknife, was De Beers’ first mine outside Africa when it opened in 2008.

The mine operated until 2015, when De Beers determined it was no longer economically viable. In 2017, the mine was allowed to flood with water. 

De Beers said to complete closure of the mine’s underground workings, all surface features will be decommissioned and sealed. Ventilation shafts will be capped with concrete.

The mine’s surface facilities include a water treatment plant, fuel storage, roadways, and an airstrip. A waste site, the North Pile, is 920,000 square metres in area and 32 metres tall. 

De Beers said the North Pile will be covered and smoothed to allow safe passage by wildlife. Water that runs off the pile will be collected in two storage ponds.

De Beers Canada and the Mackenzie Valley Land and Water Board did not respond to requests for comment by the time of publication. 

A representative from the Snap Lake Environmental Monitoring Agency said the agency could not comment on the licence. Its board will review the licence at a June 8 meeting.

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