Red Chris mine tailings dam design concerns identified
[In other words, Imperial Metals' new tailing pond is potentially worse than the one at Mount Polley. So, here is the Liberal government's big chance to act proactively - I'm holding my breath (not). *RON*]
Derrick, West Coast Native News, reposted from the Vancouver Sun, 18 November 2014
By Gordon Hoekstra, Vancouver Sun
An independent review of Imperial Metals’ Red Chris mine tailings dam design demanded by the Tahltan First Nation after the Mount Polley collapse has identified concerns.
The Klohn Crippen Berger review — paid for by Imperial Metals — found that the design is feasible if constructed properly.
However, a major design issue is the “high permeability” of the soils the two major earthen dams will be built on, which means if a fine-grained “tailings blanket” does not stop seepage, it could cause stability problems and allow significant water to leak from the storage facility, according to the review obtained by The Vancouver Sun.
KCB is recommending that during early stages of building the tailings storage facility that Imperial Metals’ designers need to monitor the water balance carefully “to prove their design concept.”
In making 22 recommendations, KCB noted that “any failure of the Red Chris impoundment will likely have a much more significant environmental impact than the Mount Polley failure.”
Unlike the Mount Polley gold and copper mine, whose tailings are considered relatively benign, the tailings at Red Chris are considered acidic and can leach potentially-toxic metals into the environment.
The mine — Tahltan First Nation members are divided on the project — will release untreated mine water into a creek that eventually flows into the salmon-bearing Stikine River. It is located in remote northwestern B.C., about 500 kilometres north by road from Smithers.
Imperial Metals officials did not respond immediately Tuesday to a request for an interview by The Sun.
But on Monday, during a conference call to discuss its third-quarter financial results, Imperial Metals CEO Brian Kynoch said the company is working through the recommendations with the Tahltan Central Council and the B.C. government.
In the aftermath of the Mount Polley tailings dam collapse, B.C. Mines Minister Bill Bennett agreed to hold back final permitting of the Red Chris mine until the third-party review for the Tahltan was completed.
Kynoch said he expected to have that permitting before the end of the year, and that commissioning of the mine would begin this month. “We are assuming we are going to get a permit to commission the plant and turn it all on in December,” said Kynoch.
Tahltan Central Council president Chad Day was not available for comment Tuesday, and council office personnel said there was no one else able to speak on the Red Chris review.
While the central council has been supportive of the mine project, the elders group the Klabona Keepers had blockaded the Red Chris site for several weeks after the Mount Polley spill over fears of a similar incident.
The review has done nothing to “soothe” fears,’ said Rhoda Quock, a spokesman for the Klabona Keepers.
Quock said she remains concerned about the potential for a catastrophic collapse but also about the potential for significant leakage. “I’m lost for words. How could our people’s livelihood be jeopardized by this?” she said.
The Klabona Keepers helped lead protests of Shell’s plan to extract shale gas in the area. In 2012, Shell announced it was pulling out.
Another concern raised in the KCB review is that the Kluea landslide, whose crest is about 300 metres from the eventual pit rim, is poorly understood. The landslide potentially could let loose and hit the mine site, resulting in an uncontrolled release of acidic and process water, says the review.
KCB has recommended additional investigation, analysis and risk assessment of the slide.
KCB has also recommended a detailed plan in the event water quality fails to meet B.C. standards, including an emergency response and other measures such as being able to capture and pump the water. KCB also recommends short and long-term water treatment.
The review identified a number of items that were lacking: emergency response plans; an operating, maintenance and surveillance manual for the tailings facility; and studies to detail what would happen if there is a collapse of the dams.
The KCB also “strongly suggested” Red Chris have a technical review board of independent, senior engineers and scientists that provide a watchdog role on tailings storage facilities. Some metal mines in B.C. have them, and they are for Alberta oilsands tailings storage facilities.