Cost estimate for cleanup of abandoned N.S. mines still 'a few years' away

An estimate of the cost of cleaning up 68 potentially contaminated historical mine sites in Nova Scotia is still a few years away.

The province announced plans in 2018 to clean up two sites that were contaminated by historical gold mines. The cleanup of Montague Gold Mines and Goldenville was initially estimated to cost $48 million, but that estimate has since grown to $60 million, and is expected to rise further.

There are 66 other sites still awaiting assessment and a cost estimate for cleanup.

"Realistically, it's going to be a few years before we work through enough of those sites that we will be at that stage," Peter Geddes, a senior staffer with the Natural Resources Department, told the legislature's public accounts committee on Wednesday morning.

Geddes said staff need to visit each site and determine how much contamination, if any, is present, and how it may impact the surrounding areas. He said the team plans to conduct an assessment on a few sites each year, and use the information to develop a system for estimating all remaining sites.

A gold rush in the late 1800s — long before environmental legislation was introduced — led to arsenic and mercury contamination at sites throughout Nova Scotia. The tailings, the material left over after the ore was processed to extract gold, still remains at many sites, and along with it, the risk of contamination.

Provincial Auditor General Kim Adair raised concerns in her December report that insufficient site investigations and environmental testing pose a potential risk to human and ecological health, as well as an unknown financial liability.

Those concerns were echoed Wednesday by NDP MLA Claudia Chender, who called the sites "a massive Pandora's box environmentally but also financially," and PC MLA Trevor Boudreau, who said it's "really concerning that we don't have the understanding of risks and liabilities."

Donnie Burke, the executive director of Nova Scotia Lands, the provincial Crown corporation responsible for remediating Crown properties, said while only Montague and Goldenville have been costed out, staff are making progress on the other sites, visiting 28 this year and using drones to get a better understanding of them.

Each site is being evaluated based on the size of the contaminated site, the chemistry, the risk to public health and the locale, including whether there's human interaction with the site. The team has developed a system to rank each site as low, medium and high risk.

So far, 12 sites have been ranked as low risk, 24 are high and the remainder are medium risk, though some may move from one category to another, Burke said.

Burke said the human health risk from the Montague site is low, and some sites on the list may not even be contaminated, or may only need relatively simple remediation steps.

"I haven't seen any that would alarm me to being toxic that I wouldn't walk on it myself without PPE," Burke said. "I don't want to alarm the public in Nova Scotia that these are significantly toxic."

Initially, there were 69 sites on the list of Crown properties with contaminated mine sites, but Burke said in an interview that one was recently removed. That site, located at Atlantic Gold's operating Touquoy gold mine, was taken off the list last month because it was determined to be included under the company's bond and remediation plan.

The ownership of Edwards Pond in Sydney Mines is in the process of being transferred to the Atlantic Memorial Park Society. That site, which was contaminated by the Princess Colliery, was remediated years ago but was never taken off the list, Burke said.

About 12 other sites will likely be able to come off the list with "fairly minimal effort," Burke said. For example, a former limestone quarry in Cape Breton has already been reclaimed, but may only require some soil and water samples to be removed from the cleanup list.

Unexpected wrinkle

As the province has dug deeper into the issue of contaminated former mine sites, it discovered "a new wrinkle we hadn't contemplated," Burke said.

At some locations, the source of contamination — such as a stamp mill, where ore was crushed in historical operations — may be located on private property, but the contamination moved onto Crown land, or vice versa.

"So of course that poses the risk, who's responsible for that waste? Is it the property owner or is it the province? It really put us in a bit of a conundrum."

The Goldenville site, identified as one of the two most contaminated former mine sites, is one such site. The province doesn't own the site where the stamp mill was located, and hasn't been able to determine who does.