Categories
Mining facts

Tailings – What are they and what is in the Mount Polley tailings?

First, what are tailings?

Tailings are essentially crushed rock, and are the leftover material after the minerals containing the “elements of interest” have been removed. At Mount Polley the elements of interest are copper, gold and silver. The minerals containing the copper, gold and silver are released by crushing and grinding the mined rock down to sand and silt sized particles.

At Mount Polley, a process known as flotation is then used to separate the important copper-bearing minerals from the rest of the crushed ground rock. The remaining crushed rock is considered waste (gangue) and is what makes up the tailings. No cyanide is used at Mount Polley.

Read more about Tailings on the Mining Association of BC’s website here.

What is the in the Mount Polley tailings?
At Mount Polley, the valuable elements are copper, gold and silver and they are found most commonly in the sulphide minerals, chalcopyrite and bornite. The leftover minerals found in the waste are piped as a slurry with water to the tailings storage facility. [ref: Community Updates 2017 Issue 3; 2016 Apr Issue 2]

The rocks that are mined at Mount Polley are around 200 million years old and represent ancient volcanic rocks and magma that intruded into these rocks. The intrusive rocks host the copper, gold and silver mineralization.

Let’s talk rocks!
The rocks which host most of the ore are made up primarily of the minerals orthoclase (potassium feldspar), albite (sodium plagioclase), magnetite (iron oxide), Ca-plagioclase (calcium plagioclase), diopside (pyroxene), garnet, biotite (mica), epidote and calcite (calcium carbonate). These minerals are all common rock-forming minerals, and represent 90% of what ends up in the Mount Polley tailings pond.

Of the other 10 percent, most are also common minerals, with a minor amount of sulphide minerals, including a little bit of chalcopyrite (0.17%) that didn’t get captured in the mill and a small amount of pyrite (0.04%).

What is unusual about Mount Polley is that, when compared to many other copper deposits (and the reason why these tailings are considered by geochemists to be chemically quite benign) there is very little pyrite (iron sulphide) and a fair amount of calcite (calcium carbonate) in the tailings.

Due to this, Mount Polley’s tailings do not generate “acid rock drainage”. This is the process that happens when sulphide minerals, especially pyrite, are exposed to the atmosphere and react to form sulphuric acid, which then can leach metals out of tailings and lead to metal mobility and potential contamination.

Mount Polley’s tailings do not have this “acid rock drainage” problem, as there is very little pyrite, and calcite acts as a neutralizing agent if any of the minor amounts of sulphide in the tailings breaks down. The vast majority of the rest of the minerals in Mount Polley’s tailings does not react easily with air or water, and are very similar to natural sand.

Categories
Remediation

Major remediation efforts to-date at Mount Polley

Mount Polley is proud of the major remediation efforts done to-date, including the building of a rainbow trout hatchery on-site in 2018 to raise more rainbow trout for Polley Lake

$70 million has been spent on clean-up, environmental impact and risk assessment studies, and remediation and monitoring of areas impacted by the spill.

Imperial Metals, with support of its shareholders and lenders, has paid for the clean-up and remediation work. No government funding (taxpayers’ money) has been spent on the clean-up or repair work done at the site. Some of the major milestones of the Mount Polley mine’s environmental remediation efforts to-date include:

  • Repair of lower Edney Creek, re-establishment of link to Quesnel Lake and installation of new fish habitat for spawners from Quesnel Lake, completed in spring 2015, with evidence of successful spawning by Interior Coho, Kokanee and Sockeye Salmon.
  • Completion of construction of a new Hazeltine Creek channel in May 2015, to control erosion and provide base for remediation of the creek itself and the creek valley.
  • Ongoing planting of native trees and shrubs in the riparian and upland areas along the creek, now totally more than 600,000 trees and shrubs planted.
  • Installation of over 6 kilometres of new fish spawning and rearing habitat in upper to middle Hazeltine Creek. Evidence of successful 2018 and 2019 Rainbow trout spawning in upper Hazeltine Creek.
  • Clean-up and repair of 400 metres of Quesnel Lake shoreline, including placement of new fish spawning gravels.
  • Re-establishment of wetlands in the Polley Flats area adjacent to the repaired TSF.

There is still work being done to complete the rebuilding of fish habitat in Hazeltine Creek. The rebuilding of the lower part of the creek will be the last part of the remediation work to be done.

Mount Polley looks forward to sharing more progress with you soon!

Categories
Remediation

The Mount Polley Team: Maintaining a Healthy Environment

Mout Polley continues to restore the environment during its current care and maintenance phase.

With 14 staff members working at the Mount Polley site, as well as several contractors, the remediation team at Mount Polley continues to work diligently to restore habitats, ecosystem and the environment at Mount Polley and affected sites.

The Mount Polley team includes environmental staff ensuring environmental recovery.  DWB Consulting Services Ltd. is also on site to provide quality control and assurance.

Some monitoring activities taking place during Mount Polley’s continued remediation include water sampling, water treatment plant sampling, plankton sampling, fish population monitoring, Hazeltine Creek monitoring and fish surveys.

Sockeye salmon in Edney Creek as a result of Mount Polley remediation
Salmon and trout are repopulating Edney Creek during Mount Polley remediation efforts.

Our efforts have proved successful to-date! Several sockeye salmon were observed in Edney Creek. Furthermore, Rainbow Trout, Coho Salmon, Lon Nose Dace and Burbot have also been identified.

Categories
Video

Mount Polley Remediation Story

This is the story of Mount Polley Remedition – from tailings spill to environmental recovery

Katie: “My name is Katie McMahen. I was born and raised here in Williams Lake and I was a member of the environmental team here at Mount Polley for a number of years. Although it was a really devastating event, as scientists we want to learn what we can out of this work that’s going on and so we’re studying methods for restoring functioning forest ecosystems, methods for rehabilitating the soil, and trying to improve best practices, really. Since day one, we’ve been doing a ton of environmental monitoring and really prioritizing fixing up the creek.

“So I love the forest, and I love working and rehabilitating the forest, so some of the coolest work we’ve been doing is not just the replanting of trees, but trying to trying to create the right conditions for those trees to thrive. So, managing the tailings, doing some techniques to really make nice little sites for the trees to grow and so that they had the proper soil conditions.”

Mount Polley remediation staff on site near Hazeltine Creek
Mount Polley staff have been working diligently for years to restore habitats, ecosystems, and the environment at Mount Polley and affected sites. The Mount Polley Remediation story is one of turn-around, innovation, and Canadian pride.

Gabriel: “My name is Gabriel Holmes, and I grew up in Likely, British Columbia, and I’m an environmental technician here, I’ve worked here since 2011. I’m really proud of reintroducing the fish into the creeks – there’s a whole bunch of things I could go on and on – but reintroducing fish into Hazeltine Creek was a real milestone, the success of the spawning last year of the rainbow trout and Hazeltine Creek, a real milestone. The vegetative communities that are developing in our terrestrial landscapes in riparian areas and then of course this year, seeing a number of sockeye salmon in Edney Creek. I’m really proud to see that occur because that’s one of our end goals that we were trying to accomplish and to see them utilizing the system today, it’s fantastic.”

Katie: “I’m super proud of the work that we’ve done here. One of the biggest challenges has just been the scale of the work that we’ve had to do, and so considering it’s only five years now since the breach, just the sheer amount of work that’s been done in those five years is amazing. When I look back it feels like way longer because I can’t believe how much we’ve done.

“We’ve really set a high precedent for what needs to happen following an incident like this and that the type of work that can be done and should be done to clean up sites. There’s a lot of information that needs to get out there about what what’s the actual environmental conditions and the fact that we have thriving rainbow trout in the creek and tons of wildlife and animals using the habitat that we’ve created. It’s going to take some years for everything to grow, but these ecosystems are well on their way to recovery.”

Mount Polley environmental technician surveys sites near Polley lake. Remediation efforts have come a long way and are almost complete. The recovery project has cost Mount Polley’s parent company more than $70 million.
Categories
Remediation

First Nations partners in Mount Polley remediation efforts

The Mount Polley remediation efforts have been underway for years. These efforts have benefited tremendously from the hard work of Mount Polley staff, Mount Polley’s First Nations partners, and local contractors and consultants from nearby Williams Lake. We think that its especially important to highlight the work of First Nations partners as the complementarity of environmental stewardship and responsible resource development is one that we are working to get right. We seek to accomplish this in partnership with all who have a stake in the natural wonder of where we live and work.

Mount Polley remediation efforts have helped restore habitats around Polley lake
Mount Polley remediation has helped restore recreational fishing on beautiful Polley Lake

Mount Polley has remediation partnerships with the T’exelcemc Nation, the Xat’sull First Nation, along with the Secwepemc Nation. First Nations partners have advised and been integral to the remediation of Hazeltine Creek and other affected areas near the Mount Polley site.

Mount Polley partnership with Xat’sull First Nation working to strengthen the shoreline of Hazeltine Creek

Seed gathering and revegetation

Revegetation has been an important part of remediation. For example, members of the Xat’sull First Nation collected willows cuttings for subsequent planting as stakes. As a result, this work enchanced and strengthened the shoreline of Hazeltine Creek. These efforts are part of the 600,000 native shrubs and trees that have been planted. This planting was done in riparian and uplands areas near and at the affected sites. It was important to plant native species to the area. Seeds from vegetative species local to the affected area were incubated and grown in nurseries. Subsequently, these were planted when grown. The practice of seed gathering and spreading has been done on an annual basis. Along with nursery efforts, Mount Polley’s work has been extensive. The remediation project is working to restore the natural ecosystem and native vegetative species. These species include the Red Osier Dogwood and Douglas fir are now thriving.

Restoration of the vegetative species at the creek shorelines has been important for building fish spawning habitats. Thousands of rainbow trout have spawned in Hazeltine Creek. These trout now make up part of the natural habitat in Polley lake. The fish from Quesnel lake and Polley lake are safe to eat.

Mount Polley tailing spill to Mount Polley recovery

As a result, we’ve turned the corner since the Mount Polley tailings spill in 2014. Indeed, the Mount Polley remediation efforts have allowed the site to turn the corner into recovery. In a few short years, with a significant investment of over $70 million, Mount Polley is making things right and is developing new methods and refining best practices along with First Nations partners. Mount Polley is doing this to show that while Canada’s resource development sector gets it right most of the time, when it doesn’t, it makes it right.

Categories
Remediation

Mount Polley recovery and remediation adds perspective

A lot has been written about the Mount Polley spill of 2014, though not so much about the remediation efforts which have been quietly underway for years to great effect. Mount Polley recovery and remediation continues. So far, over $70 million has been invested to make things right at the site and the affected areas. Let’s put Mount Polley into perspective. Local habitats are being restored. Fish spawning habitats have helped repopulate rainbow trout populations in Quesnel lake and Hazeltine Creek. The fish are biting are Polley lake!

Mount Polley tecnicians survey creek shoreline
Mount Polley is making things right

Additionally, the project has been one that has followed scientific best practices. The Mount Polley remediation effort has restored vegegative coverage in the affected areas and is seeing local wildlife thrive at the site. The project has been carried out in coordination of Mount Polley Remediation staff along with First Nations partners.

Above all, responsible resource development means setting things right in the rare instances they go wrong. We’re proud of the work that has been done and we’re showing the world that Canada leads in taking responsibility and in developing remediation practices. Truly, Mount Polley recovery and remediation means no less than just that.

Indeed, Canada has a rich traditional of resource development and environmental stewardship. We hope to maintain that legacy and the work accomplished at Mount Polley reflects commitment to that ideal.

We’d like to highlight an article that adds much needed perspective. Dr. Lyn Anglin has written about the remediation efforts at Mount Polley. Dr. Anglin was President and CEO of Geoscience BC. She was the Chief Science Officer and VP Environmental Affairs at Imperial Metals until she retired in 2018. Dr. Anglin was also on the Advisory Council at Resource Works.

Categories
Video

Mount Polley recovery receives widespread praise

Mount Polley’s remediation efforts have set a high standard in the industry as the company has taken a tailings spill and turned it into environmental recovery. Mount Polley’s efforts have been praised and labeled ‘second to none’.

“My name is Walt Cobb. I’m mayor for the city Williams Lake. We’re a resource-based community. I mean without industry we would be nothing. I mean we’ve been pretty fortunate that we’re diversified, fairly diversified. We’ve got forestry, we’ve got agriculture, and of course we’ve got mining.

“When when anything that serious happens, everyone is concerned.

“But it was a concern of the damage that was done, of course, but since then it’s a whole new story. [Mount Polley’s parent company] spent millions and millions of dollars cleaning up what had happened. I’ve been out there probably at least four times, and there is no comparison today to what what you they continue to show on the media around when the breach happened.”

Watch the whole video for more.

Mount Polley recovery efforts are almost complete. Mount Polley remediation has been praised as 'second-to-none' by experts in the field.
Mount Polley wetland restoration and revegetation
An aerial drone shot of Mount Polley remediation efforts that shows creek shoreline restoration, revegetation, and fish habitat installation.
Mount Polley creek rebuild, revegetation, and fish habitat installations