Yellowknife (July 12/06) - A warning that Giant mine is in danger of flooding and releasing arsenic into Great Slave Lake is being downplayed by the territorial government.

Last week, federal government mine clean-up manager Bill Mitchell said that Baker Creek, which flows through the mine site, could collapse into the underground mine if a 400-metre section of the creek bed isn't re-routed.

If such a collapse occurred, the mine's underground pumps would be overwhelmed and "large amounts" of deadly arsenic trioxide stored underground could escape into nearby Yellowknife Bay, he said.

But Emery Paquin, director of environmental protection for the GNWT's Department of Environment and Natural Resources, said such a disaster scenario is unlikely.

"If the underground water was allowed to rise to the level of the arsenic vaults, yes, there would be a large potential (for arsenic to escape)," said Paquin.

"The likelihood is that arsenic would be dissolved from those vaults and eventually end up in Yellowknife Bay. But in order to do that several things would have to happen."

Most importantly, he said, the mine would have to flood to a point where it comes in contact with the arsenic chambers themselves.

A decision was made last year to allow the 2,000-foot-deep mine to flood to the 1,100-foot level as a cost-cutting measure. But even if the creek did collapse into the mine, the water would have to rise another 850-feet before compromising the arsenic chambers 250-feet below the surface, said Paquin.

"The 850-feet gives plenty of time to install additional pumps or whatever measures are required to keep the water level below 250-feet," said Paquin.

"I don't know how long that would take (to flood the mine). Months? A year maybe? I don't know, but certainly there would be enough time to react."

The GNWT is not "operationally" involved in the clean-up of the now defunct mine, but have agreed to contribute $23.75 million towards the $200 million-plus project which is expected to take 10-15 years to complete.

The agreement was struck last year after years of haggling between the territorial and federal governments over who was legally liable for the clean-up after Giant Mine's owners went bankrupt in 1999.

Mayor Gord Van Tighem sits on the Giant Mine Community Alliance created four years ago by the federal government to keep residents abreast of the clean-up progress. He said they've known for a year that the creek had to be moved, although they weren't told that its collapse was imminent. Nonetheless, he doesn't think there is any need for panic just yet.

"At this point I am confident in what they're doing to this state," said Van Tighem. "The program that is in place is to avert people from having to worry."

Norman Plante, who worked at Giant from 1969 to 2000, said water flow in the creek during springtime has always been a problem at the mine. The creek bed has been moved at least once before to avoid flooding.

The clean-up strategy calls for 237,000 tonnes of arsenic trioxide stored underground - a byproduct of smelting gold ore - to be frozen and left underground.

Paquin likens it to an "ice cube in a glass of water." Rock and water surrounding the mine's 15 arsenic chambers would be frozen using thermosyphon devices and coolants pumped underground.

Groundwater in the rest of the mine would remain unfrozen.

The territorial government was initially opposed to freezing the arsenic and leaving it, but Paquin said in the end, after consultation with a peer review panel of experts, "we were satisfied that if something was going to be done now, then freezing it in place was the best available option."

Plante said he doesn't think the plan will ultimately work. "Freezing the rock is not going to solve their arsenic problem because I'm pretty sure it's going to leak," said Plante.

"Over the years, when you're blasting like that, it cracks all the rock everywhere, so you're going to have some leaks somehow."