 | Home page |  | Text size |  | E-mail this page |
Brick-by-brick demolition Giant Mine smokestack will be gone by the end of September
Cody Punter
Northern News Services
Published Saturday, September 7, 2013
SOMBA K'E/YELLOWKNIFE
With support for preserving Con Mine's Robertson Headframe seemingly running out of steam, the equally iconic structures of Giant Mine are already starting to disappear.
The Giant Mine smokestack, erected in 1953, was one of the first brick structures built in Yellowknife. The iconic structure is being taken down as part of the federal government's remediation of the site. - photo courtesy of the Government of Canada
|
The most recent casualty is the roaster smokestack, which is being demolished as part of the overall remediation of the Giant Mine site.
Only about one-third of the structure currently remains standing and it gets shorter every day.
Unlike the headframe, which will likely be demolished using dynamite, the smokestack must be taken down the same way it was erected -- brick-by-brick.
"It has been a pretty painstaking process," said Jose Cormier, communications officer for the Giant Mine Remediation Directorate.
Before demolition could begin, the smokestack had be decontaminated to remove residual arsenic. Each brick that is removed then has to be hosed down with water.
According to Jane Amphlett, general manager of the Department of Aboriginal Affairs and Northern Development's Giant Mine Remediation Team, the smokestack is shrinking by about a metre-and-a-half every day.
By the end of September, all traces of it will be gone.
At its height, the 48-metre smokestack would have been dwarfed by the 66-metre Robertson Headframe.
However, the thousands of tonnes of arsenic that were spewed out of the smokestack over the years make it a far more notorious landmark to Yellowknife's mining heritage.
In the late 1940s and early 1950s, arsenic emissions from Giant Mine totaled an estimated 7,000 kilograms a day, which equals more than 2,555 tonnes a year, according to Yellowknife historian Ryan Silke.
Other dangerous chemicals, such as sulfur and nitrogen-oxide, which are byproducts of the roasting process used to extract gold from the ore, were also emitted.
The combination of chemicals led to the corrosion of the first steel smokestack.
As a result, it had to be replaced by the brick structure in 1953, just four years after work at the mine began.
"It was really the first ever brick structure in Yellowknife," said Silke.
Although historic, the smokestack's past isn't necessarily a happy one. The release of chemicals into the air had significant adverse effects on the health of local plants and people.
It was not until 1951, after two Dene children died as a result of acute arsenic poisoning, that the mine installed pollution-control equipment to limit arsenic emissions. A Cottrell Electrostatic Precipitator allowed arsenic to be collected on electrical charged metal rods by shooting 50,000 volts into the emissions.
It was this process that allowed arsenic to be stored in underground chambers, where 237,000 tonnes of the material remains.
Several other improvements followed, including the installation of a baghouse in 1958, which allowed excess dust to be collected before steam created during the roasting process was released through the stack.
According to Silke, after the baghouse was installed, emissions at the mine were reduced by 98 per cent of their original output.
While today the mine is vilified for its impact on people's health and the environment, Silke said over the course of its operation, the mine was at the forefront of improving mining techniques.
"The guys who designed this place were kind of like mad scientists trying to get this right," said Silke.
"Not just for the purpose of getting gold out but also for limiting the environmental hazards of the operations."
Indeed, by the 1980s the mine had reduced its emissions to less than 50 kg of arsenic a day.
"We came a long way to correct those mistakes," said Silke.
But as Con Mine began to develop new methods for extracting gold, which did not require the roasting of arsenic, Giant Mine was no longer making enough profit to justify improvements.
"By then, Giant had become such an antiquated operation. It was really difficult to change."
The inability to remain profitable led to Giant Mine owner Royal Oak Mines Ltd. to declare bankruptcy in 1999.
Five years later, the mine was closed for good.
Even though all visible traces of the mine will be gone in the next few years, Silke says it is important to remember the way the mine shaped Yellowknife then and into the future.
"It's definitely something that lingers," said Silke. "It's part of our legacy."
The cleanup of the Giant Mine site is expected to cost nearly $1 billion.
| 
