Home page

Text size

E-mail this page

SOMBA K'E/YELLOWKNIFE
A coolant leak at the Giant Mine site has forced the shutdown of the Arctic Foundations Freeze Plant, the structure that freezes deadly arsenic trioxide in blocks kept deep underground.

Adrian Paradis stands near the thermosyphons at the Giant Mine site. - Danielle Sachs/NNSL photo

On June 28, inspectors at Giant Mine noticed low pressure in the condenser. The system was shut down and locked until a refrigeration specialist could inspect the surrounding area.

Adrian Paradis, acting manager of the Giant Mine Remediation Project, confirmed there had been a leak but as of Wednesday the exact source and reason for the leak could not be determined. He couldn't say when the refrigeration system will be turned back on.

It was the hybrid system that leaked, which is the system that triggers the operation of the thermosyphons to cool the underground chambers.

In total, 385 kilograms of R-507 halocarbon refrigerant leaked, but there is no ground contamination because as soon as it's exposed to air it turns into gas.

The immediate effects of contact with the chemical include frostbite and dizziness, or unconsciousness when inhaled.

Paradis said there is no risk to the environment or public.

He said the arsenic blocks are so frozen a brief shutdown won't cause any melting.

"Even if the system was entirely shut down, after 50 years you would only get a thin layer starting to thaw," he said.

Giant Mine has 237,000 tons of arsenic trioxide buried underground. A by-product created by roasting gold ore, the site of the federal government's freezing test is an 11-storey chamber underground which holds the arsenic. It's one of 15 arsenic trioxide-filled chambers and stopes at the mine. The freezing test began in March, 2011 with the ultimate goal of freezing all the arsenic - quite likely in perpetuity.

It's considered one of the most contaminated sites in Canada, and once remediation starts it will take 10 years to clean up the site, said Paradis.

Kevin O'Reilly, a mining watchdog and executive director of Alternatives North, said overall he was pleased with the communication about the spill.

He was notified Friday and later given a copy of the spill report.

"I got a call from Adrian Paradis with the Giant Mine team. It was quick and appreciated," O'Reilly said.

"It's an improvement over the Baker Creek notification. I think that's a good step."

While O'Reilly said he doesn't foresee any environmental or human health hazards from the leaked gas, he said it speaks to the larger issues of long-term care and planning.

"Here we are, less than two years into this test freeze, and we've already had a major incident that caused a shutdown," he said, adding he understands accidents and malfunctions in this type of system are inevitable.

Another issue O'Reilly highlighted was the lack of commitment from the federal government.

"How do we make sure there's always money for the site?" O'Reilly asked.

"This question has been asked three or four times and there's never an answer. If the federal government wants to freeze this forever, they need to come up with a solution for long-term funding."

It doesn't help that the 24-hour emergency number for Environment Canada was out of service when the spill happened.

"Spills have to be reported both to the GNWT and Environment Canada," said O'Reilly.

"The 24-hour emergency spill line wasn't in service, I called it myself."

The GNWT's emergency report line was working fine.

The total cost of the Giant Mine remediation project is an estimated $479 million. Once the site is completely cleaned up, save for the stored arsenic, it will cost around $1.9 million per year in upkeep and maintenance.

We welcome your opinions. Click here to e-mail a letter to the editor.