Through all the studies and reports done on the underground storage of arsenic trioxide at Giant mine, three things are clear: the problem is huge, complex and will not be solved anytime soon.
Richard Gleeson
Northern News Services
Yellowknife (Mar 30/01) - In a light-hearted moment during a public presentation on the current clean-up work at Giant mine someone joked that the tailings deposited on the edge of Back Bay make a nice beach.
Life-time Yellowknifer Bob Bromley failed to see the humour, as he later pointed out.
"It was an incredible beach for swimming at when I went over there in my freighter canoe," Bromley said. "And I also had cancer a little later. Could be a coincidence, who knows?"
The toxic substances in the tailings, which have been sitting on the shore of the bay for decades, likely leached into Great Slave Lake long ago, Bromley said.
The Workers' Compensation Board reports it has accepted 24 claims, mostly related to allergic reactions or inhalation and involving no time lost, related to arsenic in the mine since 1980.
Surface contamination is just the tip of the iceberg where Giant is concerned.
What's underground has the destructive force of a nuclear bomb, with upwards of $3 million required annually to prevent it from exploding and contaminating the entire North Slave region.
Worse than it appears
The explosion of 265,000 tons of arsenic trioxide dust stored in 15 vaults beneath Giant mine would, experts believe, take place over a number of years.
But it is clear that if it was unleashed on the environment through contact with the water table, the arsenic trioxide dust would be no less deadly than a nuclear blast.
"If you were to take two Asprin-sized tablets, (of arsenic trioxide) that would prove fatal," said Dave Nutter, the federal official leading an initiative to develop a long-term solution to the problem.
It has been estimated there is enough of the water-soluble poison in the mine to fill the 11-storey Precambrian Building seven times over.
No rush
Despite the catastrophic potential of the problem, the Department of Indian Affairs and Northern Development (DIAND) officials are satisfied the underground arsenic does not present an immediate threat to the environment. Water is seeping through some of the vaults, sealed by bulkheads up to 50 years old, carrying arsenic trioxide into the mine proper. All of the water is being captured in a series of sumps deeper in the mine.
"Everything is inclined so (the water) flows to a central point," said DIAND official Neil Thompson.
The sumps in which the water is ultimately collected are 600 metres below the surface. At their deepest point, the vaults are 75 metres down.
The belief that all the contaminated water is being collected was backed up in a study, carried out from 1992-94, on the water in Yellowknife Bay and Back Bay.
"There's no indication of contamination from any of the studies we've done of water quality on Back Bay," Nutter said.
Accounting for the time it will take to develop a plan for dealing with the arsenic, getting the appropriate approvals and implementing it, the pumps will continue pushing water up to the surface for treatment for at least another two decades.
Not a priority
The complex task of deciding on a long-term solution is made no less daunting by an apparent lack of federal interest in the problem. Last year funding did not arrive until 11 weeks into the fiscal year, and when it did there was less than half of what was requested. The next financial year begins tomorrow.
"We feel we will get some money," Nutter told 18 people who showed up for an update on the mine clean-up Wednesday. "We don't know when ... I would hope that, at the minimum, we will see something in the order of $2 million."
The federal government became legally responsible for dealing with the problem in 1999, when former owner Royal Oak went into receivership.
"I'm just shocked they don't have a budget," Bromley said. "How can you carry on a step-by-step program when you don't know if you have funding?"
DIAND is currently embroiled in a battle with a Toronto-based insurance company responsible for a $1.9 security deposit Royal Oak put up for Colomac and Giant. The money is already spent, but the insurance company maintains because Royal Oak is bankrupt it need not pay out.
Making a choice
A pre-feasibility report due this summer is expected to reduce the number of options for dealing with the arsenic to three or less.
The report will consider the effectiveness, cost and risks of a number of solutions, ranging from leaving the arsenic trioxide in the vaults and artificially inducing the re-establishment of permafrost to removing it and stabilizing it by processing it in an autoclave or stabilizing it in substances such as bitumen, glass or cement.
"The implications of going down one road in terms of management of arsenic trioxide are very significant ... we have to be sure we've chosen the right option," Nutter said.
The most sensible solution, extraction, is fraught with technical challenges. Because of the toxicity of the arsenic, most of the work would have to be done robotically.
Through contact with water, and up to 50 years of compression under its own weight at least some of the arsenic trioxide has likely transformed into something other than the powder it once was. Some of the vaults are regularly shaped rectangles, others are irregularly shaped caverns.
"If we empty the vaults out as best we can and still leave one per cent in there, are we still going to have to pump and treat forever?" Nutter said.
