Giant Mine headframe future questionable
Landmark considered "unacceptable risk" by project leads
Meagan Leonard
Northern News Services
Monday, March 9, 2015
SOMBA K'E/YELLOWKNIFE
This summer could see one of this city's oldest mining landmarks removed from the skyline.
TerraX minerals strategic and community adviser David Connelly listens as his questions about air quality monitoring are answered at a Giant Mine public forum Feb. 26. - Meagan Leonard/ NNSL photo |
After the roaster complex was demolished at the former Giant Mine site last year, the C-Shaft Headframe is next on the chopping block - deemed an "unacceptable risk" by project leads.
Engineering manager Jane Amphlett says eventual removal of the structure was always part of the remediation plan but has been pushed forward due to dangerous deterioration.
"We understand that it has a history Š but this is a safety concern and that's our primary worry here," she told Yellowknifer.
If the headframe were to collapse, she said the site could lose power threatening monitoring stations and underground operations. Wood debris falling off the structure also poses a risk to workers.
However, because of its ties to the community, she said they are looking at alternatives before making a final decision.
"We'll be addressing the wood part of the structure at minimum and then our engineers are going to confirm whether in fact the whole structure would need to come down. We'll know that over the next few months," she said.
NWT Mining Heritage Society co-ordinator Tracey Breitbach says they will be sad to see it go but understand safety is the first priority.
"We understand that it's in pretty bad shape," she said. "The timber is pretty rotten and there hasn't been anything done to maintain it."
Breitbach said the society's focus has been on the smaller A-Shaft headframe located near the site of the future mining museum but she hopes at least one can be salvaged.
"We hope the government will recognize it is important to Yellowknife and if the A-shaft is found to be structurally unsound then at the very least a replica will be constructed on the same site."
At a public forum Feb. 26, Amphlett said the roaster was the biggest threat to public health and its demolition has made the area significantly safer. However, some concern remains regarding storage of the roaster refuse currently bagged and placed in shipping containers over the tailings pond. During a municipal services meeting Feb. 23, project director Natalie Plato confirmed there had been one known leak in June but it had been reported and secured. Amphett reiterated this after the open meeting.
"A small amount of material did leak out of one of the containers," she said. "That is an actively managed area so we inspect it regularly it's in our tailings pond. It's secured. When it was discovered, we cleaned it up and all the water in that area is treated."
She says eventually the stored material will be frozen underground with the rest of the arsenic trioxide -- the containers are merely a temporary solution.
"The containers are designed to protect the bags from weather so that sun or rain can't deteriorate the bags."
Later this year, a paste created from mine tailings, water and cement will be pumped into underground chambers or "stopes" to stabilize mine walls and prevent collapse and flooding, the public heard.
Former Giant Mine draftsman Dave Ritchie said he is curious how this may affect future industry prospects at the site.
"If anybody wants to look for gold down there, is the mine still for sale?" he asked.
Although discussions about future site plans have started swirling, remediation is expected to take ten years with air and water monitoring continuing for the next century. At this point, Amphett says their focus is on the cleanup and the site will remain under government jurisdiction.
"We certainly are open to talking with ... groups about what people are interested in having out there," said Amphett.
David Connelly, strategic and community adviser for TerraX Minerals, attended the meeting because he is involved with the Yellowknife City Gold Project a few kilometres north of the mine. In response to the still as-yet determined final remediation cost which will fall to the taxpayer, Connelly said Giant Mine is the city's legacy and it would be counter-productive to find fault with an organization simply doing what was typical for the time.
"It did at the time provide the means for which Yellowknife was built and a number of benefits came from it but they weren't managed in the way we manage today and they used technology that was much more dangerous," he said. "We don't have any other alternative than to use public funds to make the environment and the air of Yellowknife safer."
Yellowknife resident Ed Hoeve has been following the remediation process closely and says he isn't sure the freeze block method is the best option for long-term stability.
"I don't think it's an acceptable permanent solution it's a temporary fix in my opinion," he said. "The ultimate solution is to get it out of there and get rid of it."
Although he feels the site risks have been exaggerated, overall he says he is happy with how the project is progressing.
"I think the risks are probably a bit overblown or overstated, but I recognize we live in a risk-averse society they've got to be over cautious," he said. "I don't get the impression that they are trying to pull the wool over anybody's eyes."