Ajax says tailings plans don't pose a risk

By Tanya Cronin
January 20, 2016 - 5:16pm Updated: January 20, 2016 - 5:48pm

KAMLOOPS — It was the largest mining waste spill in Canada's history. August of 2014, more than 24-billion litres burst through the Mount Polley Dam, into their watershed. An environmental disaster that prompted an extensive review.

"We committed very early on after the Mount Polley incident, to take any lessons learned from Mount Polley and to implement them at Ajax, that's what we've done," says Clyde Gillespie, KGHM-Ajax Project Manager.

The consequences and overall costs of the Mount Polley disaster in the Cariboo, put pressure on KGHM-Ajax to take a closer look at the proposed project's tailings plans. Project Manager Clyde Gillespie says the company is sticking with a large tailings pond, but it is now so-called thickened tailings.

"At Ajax we have designed a buttress that is actually larger than the embankment itself, and the two main embankments will be fully buttressed, huge buttress and when the engineers tried to find a failure mechanism to do the dam breach and in additionional study they could not get it to fail, it would not fail with the software they used." 

In its summary, KGHM-Ajax assures the community there is no threat. The company's decision to switch from dry stack  to wet tailings is not only a cost-saving measure, but the most ideal configuration for a project of this size.

"The technology that's utilized for dry stack is used fairly commonly with operations up to 20,000 tonnes per day is the amount of ore they process. At Ajax we've at more than 3 times that with 65,000 tonnes per day, hte scale up from 15,000 to 20,000 tonnes per day to 65,000 is a significant scale up and that can lead to several challenges."

The company's application to the Environmental Assessment Office outlines dry stacking has never been used in another mine the size of ajax. It states wet tailings make the best economic and environmental sense, and contain more solids, reducing the likelihood of a breach.

"What it means is we pump out a lot less water out to the tailings facility, there's a lot less water stored in the tailings facility because the tailings are thickened in a process to remove that water at the processing facility and it's re-used in the process."

The Mount Polley disaster created concern among many. KGHM-Ajax  is confident the public can trust, that the proposed copper-gold mine South of the city will be a safe operation. 

"I have all confidence this will be a facility that can be designed as it currently is constructed, maintained, operated and monitored over the long term in a stable conditions with no impacts to the community or the environment."

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