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Sustainable Development

Elliot Lake hailed as reclamation success story

A former uranium-mining town in Northern Ontario got a new lease on life when two previously competing companies worked toward a common goal.

Denison Mines and Rio Algom Limited, two mining powerhouses in Elliot Lake, worked co-operatively to decommission and rehabilitate the mine sites that shut down in the ‘90s. The efforts of the two companies have resulted in a remarkable recovery of the city’s watershed.

“The recovery rate has exceeded projections by an order of magnitude,” said Ian Ludgate, manager, Denison Environmental Services. “We’re where we thought we’d be 100 years from now.”

This means the water is safe for swimming and fishing, and waterfront lots in the city are being sold to retirees looking for a lifestyle change.

Ludgate attributes the fast environmental recovery to the fact that they are still treating the water. “Overall, we’re quite pleased with the recovery…in 1990, there was a mine there. Who would have thought 20 years later there would be cottages and homes on Quirke Lake? People are catching and eating the fish.”

Once known as the uranium capital of the world, the City of Elliot Lake has been transformed from a rugged mining town into a flourishing retirement community.

It is situated almost halfway between Sudbury and Sault Ste. Marie, about 20 minutes north of Highway 17. Landscaped with cottage-lined lakes, parks, nature trails, golf courses and ski hills, it is a far cry from the mining boom town that sprang up in the 1950s.

Post World War II

The first discovery of uranium was made in 1948 by Carl Gunterman and Aime Breton, who used a Geiger counter to determine the radioactivity in the rock. This sparked the interest of geologist and prospector Franc Joubin. Once he nailed down the geology and uranium content in the rock, he joined forces with financier Joe Hirshhorn.

The uranium was hosted within rock units referred to as “The Big Z.” The ore reefs were the result of river channels containing eroded and weathered material that included uranium-bearing minerals from the surrounding granitic terrain, according to Sault Ste. Marie resident geologist Anthony Pace of the Ministry of Northern Development, Mines and Forestry.

Staking rush

Once uranium was discovered, the Elliot Lake mining camp was born, spawning 11 producing uranium mines between 1953 and 1996. Some mines were independently owned, but eventually, Denison Mines and Rio Algom Limited became the two principal operators. At its peak, the mines employed 4,500 people.

The real mining blitz occurred between 1953 and 1958 when 12 mines and 11 mills were built, producing uranium for the United States Atomic Energy Commission, said Ludgate.

Ups and downs

In the 1960s, mining activity slowed significantly when U.S. contracts ended. By the ’70s, there was renewed interest in uranium. OPEC drove the price of oil up. Consequently, some mines reopened or ramped up production, reviving the economy.

The mines operated into the ’80s to supply overseas utilities as well as Ontario Hydro. By the mid-80s and early ‘90s, changing market conditions and a cancelled Hydro contract brought mining to a standstill. Successive closures occurred from 1990, culminating with the cessation of production at Rio Algom’s Stanleigh Mine in 1996.

Closure

The mine shutdowns significantly reduced employment. Only a handful of people from each company remained to decommission and demolish the remaining mines. It was a huge blow to the area.

By this time, northern Saskatchewan’s Athabasca Basin reserves were discovered and it was clear Elliot Lake’s low grade deposits could not compete.

“We’d be lucky to find two pounds of uranium per tonne of ore,” said Ludgate. “Whereas in Saskatchewan, some grades are in excess of 200 pounds of U3O8 per tonne of ore – two orders of magnitude of higher grade uranium.”

A new plan

Two things happened: A new economic strategy geared to retirement living was unveiled and the mine sites were cleaned up and reclaimed. Reclamation work has reaped benefits not only for the environment, but also for the health and safety of the residents of the city.

Denison Mines created Denison Environmental Services based on its decommissioning expertise.

Reclamation work in Elliot Lake took place between 1990 and 2000.

Decommissioning

A federal environmental assessment was performed on Rio Algom’s Quirke, Panel and Stanleigh Mines and Denison’s Stanrock and Denison Mines, said Debbie Berthelot, reclamation manager, Rio Algom. Historic sites that remained dormant since the 1950s were brought up to the same standards.

Projects like tailings relocation, capping mine openings, demolition of buildings, landscaping, and management of the water treatment plants were part of the decommissioning process.

Denison owned three mines – Dension, Stanrock and Canmet – with three tailings management areas (TMA) totalling about 68 million tonnes spread out over approximately 310 hectares. Rio Algom had about 100 million tonnes of tailings in eight TMAs that covered about 950 hectares.

Each tailings site was assessed separately. Hydrology, water balance, geochemistry, geotechnical and dam stability and potential environmental impacts were taken into account.

One million tonnes of tailings were returned underground. However, more was not considered because processed ore expands 50 per cent more than its original size and the pillar-and-room mining method made it costly.

Vegetation and gravel covers were briefly considered, but proved to be too expensive.

Covering tailings with water was the preferred option and used in the majority of cases. Barium chloride was used to remove elevated radium levels in water and lime helped control low pH levels.

“Water cover for the climate of Northern Ontario was deemed a reasonable option and is still the best choice,” Ludgate said, although some sites required vegetation covers.

Two consulting groups, Golder Associates and SENES Consultants Ltd. (Specialists in Energy, Nuclear, and Environmental Sciences), provided expertise and guidance during the process of decommissioning the mines.

By 1997, it was recognized that the experience and knowledge gained throughout this process could be employed elsewhere, so Denison Environmental Services was launched. Eighty employees strong, it provides mine decommissioning, and care and maintenance services across the country.

Water monitoring

In 1999, the water monitoring programs were consolidated for the entire Serpent River watershed. This program replaced the previous Receiving Environment Sampling program in order to reduce duplication and track improvements in the watershed over time.

The tailings are on long-term care and maintenance and will continue to be into the future. “We’re committed to the area and will be there managing the site for a long time,” Ludgate said.

With the changing demographics of Elliot Lake, Denison and Rio Algom have also changed their outreach programs to involve public information sessions, site tours, newsletters and a website about the closed mine sites, reclamation work and ongoing maintenance.

www.denisonenvironmental.com

 

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