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Environment

GNWT files plan to address concerns at old mines nobody wants


Six former mines that exist in a form of post-devolution limbo will soon begin receiving fresh scrutiny from the NWT government.

The territory, in part pressed into action by a complaint under the Environmental Rights Act, has filed a plan to carry out work that will provide a clearer picture of the environmental risks the mines present.

The Ptarmigan, Tom, Tin, Burwash, Rodstrom and Crestaurum mines, scattered to the north and east of Yellowknife, were all gold-mining operations. No government currently claims ultimate responsibility for their clean-up.

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When devolution took place in 2014, the six former mines were listed as “excepted waste sites,” meaning the terms of devolution did not apply to those sites and they would instead be the subject of later negotiations between the federal and territorial governments.

Eight years later, those negotiations are ongoing.

The federal government completed environmental site assessments of the mines in 2013 and the territorial government conducted follow-up work in 2017, but the sites need a fresh assessment to understand the state they’re currently in.

The concern that excepted waste sites’ environmental and health risks aren’t being properly addressed was raised in a complaint filed by a member of the public last year.

That complaint focused on the “clouds of dust and debris” that blow across Highway 4, the Ingraham Trail, from the Ptarmigan Mine’s tailings ponds.

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A GNWT map shows the Ingraham Trail bisecting the Ptarmigan mine and one of its tailings ponds
A GNWT map shows the Ingraham Trail bisecting the Ptarmigan mine and one of its tailings ponds.

Ptarmigan was a gold mine in the 1940s, 1980s, and 1990s. Nearly 300,000 tonnes of tailings, or mine waste, remain at the site.

Making use of the Environmental Rights Act – which allows residents to apply for an investigation if they reasonably believe something is happening that may harm the environment – the complainant spurred the NWT government into acknowledging that a fresh risk assessment was needed, alongside work to stop those dust clouds.

A regulatory application filed by the GNWT last week sets out some of the initial actions to be taken.

At the Ptarmigan site, the NWT government plans to install boulders this summer that will prevent easy public access to the old mine. Boulders have been installed before but some of the old ones have since been moved, presumably by people whom the rocks did not deter.

Some fencing repairs at Ptarmigan were completed last November, the application states, but more work may be required. (The Tom and Tin mine sites, which stretch out toward Prosperous Lake from Ptarmigan, will also have fencing work where needed.)

The main activity at Ptarmigan will be dust suppression. This summer and at least once a year after that, the territory proposes to send a contractor to the site with water from Yellowknife “to mitigate the effects of wind-blown dust on the surrounding area.”

All six sites will then receive fresh environmental risk assessment work. Samples of soil, groundwater, surface water and sediment will be taken at each site, with new groundwater monitoring wells installed.

An NWT government map shows the six excepted waste sites around Yellowknife.

Last year’s investigation into the Environmental Rights Act complaint concluded a human health and ecological risk assessment, or HHERA, will be needed at Ptarmigan Mine.

The NWT government, responding to that investigation, said it would “recommend at the negotiations table that an HHERA be carried out by the responsible government” – an example of the uncertainty caused by the former mines’ continued existence as excepted waste sites.

“These findings do not necessarily mean that there is risk to the environment or to people in the area,” the territorial government said in October last year.

“The human health and ecological risk assessment will determine the level of risk.

“It is important that residents avoid the Ptarmigan mine site, including the tailings area, to reduce any risk.”

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