Giant site, giant changes
Mike W. Bryant
"It's one of the worst in terms of arsenic trioxide," says Bill Mitchell, Giant Mine's federal mine clean-up manager.
"You can rank it up there with the big ones like the Sidney tar ponds."
If there's anything "nice" about arsenic, says Mitchell, it's that it doesn't build up in the body like lead or mercury. A large (about a teaspoon) or continuous dose is necessary for it to kill.
Giant is dirty, and in some areas the arsenic count is almost off the chart, but Mitchell says Yellowknife residents are going to see some big changes over the next few years.
It's all part of the federal and territorial governments' plan to clean up the mine's surface, which Mitchell estimates will take about 10 to 15 years. The cost is estimated at $60-100 million.
Starting this fall, a good portion of arsenic-contaminated Baker Creek will be re-routed away from the arsenic trioxide chambers beneath it.
It's just too risky to leave the creek where it is while the government attempts to freeze the arsenic underground, says Mitchell.
Last week, the creek teemed with Arctic grayling, which have slowly started to come back in recent years to spawn.
Mitchell believes that the fish habitat will only get better after the creek is moved. "The idea is to create a natural channel with a flood plain so it would become very good fish habitat," says Mitchell, before pointing to the large open pits beside the creek which could one day be fishable water a few minutes' drive from town.
The Ingraham Trail, which cuts through mine property, will also be moved, says Mitchell - either nearer the shore of Great Slave Lake or to the other side of the open pits.
"That will give us a lot more space for the creek," says Mitchell.
An onerous job, says Mitchell, will be the removal of up to 400,000 cubic meters of contaminated dirt from the mine site.
Some areas, particularly those close to the mine's roaster complex contain as much as 18,000 parts per million of arsenic trioxide. The maximum allowable for residential standards is 160 parts per million.
"The most highly contaminated stuff will go into an empty chamber, then the balance will go into the frozen zone within (one of the pits)," says Mitchell.
Shrouded in plastic
The roaster stack - the most prominent structure on the Giant Mine site - will be torn down brick by brick. Other buildings will be shrouded in plastic to prevent asbestos and arsenic dust from scattering, and then imploded.
The remains of the most contaminated pipes and buildings - the roaster, cottrel, and baghouse - will be taken underground and frozen, says Mitchell.
"What we can salvage we will," he says.
"Other stuff will go into the non-hazardous waste landfill. Any hazardous material, such as the asbestos, will have to be disposed of separately."
Tailings ponds, of which there are four, not including the polishing and settling ponds, will be "capped." This involves layering them with crushed rock and silty clay over which plants will eventually grow. Manure shipped in from Hay River will serve as fertilizer.
"Vegetation will dry out the tailings ponds," says Mitchell.
"The idea is that we prevent an influx of water into the tailings."
Former mine workers interviewed by Yellowknifer earlier this month claimed that raw arsenic trioxide was routinely dumped into the tailings ponds whenever there were spills.
Mitchell says he finds it hard to believe, but there is no way to know for sure.
"It's possible some of those things happened," he says.
"We just have no documentation.
"Unfortunately the inspection regime at the time was just not what it is now.
"It's just too bad these guys didn't report these activities at the time. It doesn't do us a lot of good now, unfortunately."
The plan, he says, is for all the water from the tailings ponds to be drained and purified through the mine's water treatment plant.
Despite their efforts to clean it up, Mitchell doubts the mine site will be turned into a bedroom community any time soon.
"You can never reach that," says Mitchell.
"It has to be realized that this was a historic industrial site. That's all it's been used for.
"It just seems strange to me that people would even consider building houses on this site."
Fuel up station
He imagines that one day the site will be used for trucking companies to fuel up and bunk staff on their way to the diamond mines further north up the winter road.
One thing for certain, says Mitchell, the old mine site that many Yellowknifers have grown accustomed to, will be going through some changes very soon.
"On the surface there really isn't a lot of options," he says.
"Everything we see is going to be gone."