Nova Scotia tenders investigations into impacts of more than 70 former mines

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Last March, after Nova Scotia identified nearly 70 sites it plans to assess and potentially remediate, officials have now added five more sites to its long list of areas contaminated during the province’s first gold rush era.

Nova Scotia Lands has issued a tender seeking companies to study the five added sites — Gold Brook Lake, Seal Harbour, Lake Enon, Mooseland mine and the former steel plant on Ocean Street in Sydney Mines — and determine remediation options for each, as well as the human health and ecological risks. The work will be considered environmental investigations.

In most cases, the province is looking for more than a decade’s worth of geotechnical experience at contaminated sites.

The two sites which officials predicted to be the most contaminated on the overall list, Montague Gold Mines and Goldenville, have already been assessed and will cost an estimated $60 million to remediate.

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During the late 1800s, contaminants such as arsenic and mercury were often dumped on land or in waterways around the gold mines due to an absence of environmental oversight. Mercury extracted the gold, and the arsenic naturally found in the rocks was released in large quantities through the mining process.

Now, the province is currently beginning what many see as its fourth gold rush era, particularly on the eastern shore.

Among the five new additions to the list, the Gold Brook Lake and Seal Harbour mine sites operated in the late 1800s to early 1900s and have been dormant since the 1950s. “During operation, large quantities of mine tailings were slurried directly into the upper reaches of Gold Brook,” the tender document background states. “These tailings may be seen on the floodplain for at least four km downstream of the Richardson Mill site.” These mine tailings contain high concentrations of arsenic and mercury.

The new addition of the Ocean Street Former Steel Plant Site located in Sydney Mines is from 1902 and consisted of many coke ovens. Coke is the main fuel used in the steel making process. The site now contains significant remnants of slag piles, crumbling building foundations, coaly waste rock, and an approximate area of 15,126 square metres of coaly mine tailings, according to the tender document.

Mooseland became the first officially designated gold district in Nova Scotia, and was active between 1861 and 1934, recovering approximately 3,865 troy oz. of gold, according to the tender document. Tailings sampling of the site’s tailings area conducted in 2003 indicated elevated concentrations of arsenic and mercury. The total area considered to be potentially contaminated is 34,093 square metres (8.5 acres), with an estimated 8,217 tonnes of tailings.

The former Lake Enon Mill Site was developed in the mid-1960s and was operational from 1969 through 1975 or 1976 by Kaiser Celestite Mining. The tender document states that known or suspected contamination includes mine rock dumps, a moderate sized tailings area and domestic garbage. In 2018, Dillon Consulting reported evidence of ongoing illegal dumping on-site.

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