Con Mine clean by 2017
Majority of reclamation projects to be completed over the next two years; water treatment will continue for 25
Meagan Leonard
Northern News Services
Thursday, May 7, 2015
SOMBA K'E/YELLOWKNIFE
All major reclamation work at the former Con Mine site should be completed by 2017, the public heard at a meeting Tuesday morning - including demolition of the iconic Robertson Headframe.
Miramar Northern Mining Co managers Scott Stringer, left, and Dwight Grabke answer questions about the Con Mine reclamation status report at a discussion session held at the Explorer hotel Tuesday. - Meagan Leonard/ NNSL photo
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The meeting held at the Explorer Hotel brought representatives from Miramar Northern Mining, the Mackenzie Valley Land and Water Board and Department of Environment and Natural Resources together to discuss and clarify reclamation plans for the public.
Based on updated figures and work completed in 2014, the reclamation security held in trust is just under $11.9 million, which will cover the cleanup.
Reclamation security is based on an estimated total cost of mine rehabilitation. Funds are incurred over the mine's lifetime to help pay for closure and rehabilitation and avoid having the cost borne by tax payers - as is the case with Giant Mine.
Remediation plans slated for this summer include removal of 63 structures, installation of vegetative islands, covers on hazardous waste areas and commissioning of the new water treatment plant.
Up until this point only surface runoff has been managed at the site, but the completion of a new water treatment plant this July will allow groundwater to be treated as well.
"Our hope is to be treating water as early as July or August," said Miramar manager Dwight Grabke.
The old water treatment plant will be demolished in 2016.
Security funding has been increased to accommodate the demolition of surface structures but an updated figure on what it will cost to remove the Robertson Headframe is still undetermined. A 2008 estimate suggested it could be well over $300,000.
"A tender for that will be available in the near future," said Grabke. "It will be based on the price of recycled steel, labour market and cost of hiring a demolition company."
All of the mine openings including shafts, stopes and raises have now been closed off and are ready to be covered by vegetation seeding this year, said Grabke.
Engineer John Brodie asked what the rate of success would be for the plantation given the site's soil contamination and whether money had been set aside for replanting in the event the first run is unsuccessful.
"With respect to re-vegetation, these tailings have had very little vegetation for decades. Will we need to go back and reestablish vegetation efforts?" he asked.
Grabke responded that the nature of the arsenic at this particular site makes it less likely to be absorbed by plants but it is something they will have to look into on an as-needed basis going forward.
"We should be able to establish a self-sustaining cover with the funds available," he said. "There is always a chance it won't work and we'll have to address it at that time."
Much of the hazardous waste disposal has been completed and a protective liner is expected to arrive later this month to be placed over top of the waste area. Slopes will also be built up to improve drainage and water flow.
Environmental activist and Yellowknife citizen Kevin O'Reilly asked whether the tailings pond and hazardous waste site would be protected by fences and signage for public safety. Grabke said a barrier of rocks would be placed around the area, along with signs at a relatively low cost.
O'Reilly also wondered what the current toxicity levels of arsenic in the soil were - previously reported to be anywhere from three to 150 parts per million. Grabke said they currently do not have exact numbers.
"We don't have specific numbers for concentrations," Grabke answered. "It's a swamp so there were pockets here and there but no specific numbers."
Opening in 1938, the mine is Yellowknife's oldest gold producing site and its 25-storey headframe has been a fixture on the city skyline since 1975. Production ceased in 2003 and treatment of water from tailings ponds is expected to continue for up to 25 years.
