Groundwater remediation at Giant Mine

Groundwater remediation project team

Caelan Accili, Ben Alberga, Carla Conradie, Audrey Lee and Cameron Shepherd

The challenge

The Giant Mine in Yellowknife, which closed in 2004, has left a devastating environmental legacy that includes 237,000 tonnes of arsenic trioxide dust – a lethal and water-soluble substance that is stored in underground chambers. We were asked to design a year-round treatment plant to treat the groundwater that is contaminated with dissolved arsenic to make the water safe for release to Yellowknife Bay, which is the source of drinking water for the city and surrounding communities.

Giant Mine Remediation Process

Our design process

There is currently a temporary system in place to treat the contaminated groundwater, but it can only run half the year – which is doubling the treatment time – and operates by pumping the water from the tailings ponds underground into storage tanks. However, we know that the arsenic trioxide waste will eventually find its way through groundwater movement up into a local water body.

Our plan is to take the groundwater – which currently has 49 mg/L of arsenic compared to allowed levels of 0.01 mg/L – directly from the underground reservoir, pumping up a flow of 2,600 m3/day through a C shaft into our plant for treatment. Our process starts with a flow equalization tank to provide stable flow for the downstream treatment process. The next steps are oxidation and precipitation, and clarification and filtration. A two-step ion exchange process first targets arsenic and antimony and then isolates zinc and lead. These chemicals are then sent to waste treatment and the treated effluent is pumped and discharged to Yellowknife Bay.

We developed a plant layout for our planned process that estimates water and energy requirements, as well as facility size and required labour. We also completed an economic analysis to estimate the capital and operating costs over the 20-year life of the plant.

Image
Plant Layout by the ENVL team

The social considerations of this project were very important to us, particularly given the history of this mine in the community. We developed a stakeholder engagement plan with Indigenous Peoples and residents, local government and regulatory boards.

Integrated Water Management at UBC

What excited us most

"It can be easy to get lost in the technical details. However, when you zoom out, the purpose of this project is very meaningful."

We generally relied on tried-and-true treatment options, but our proposed ion exchange process incorporates some new technological innovations. Learning about this process and connecting with vendors to learn more about the specifics of how it could be applied to this project was very interesting.

"This is impactful work and it aligns with our values and what we have been studying over the course of our environmental engineering degrees.

There are a lot of engineering details to account for when designing a treatment plant to ensure discharged water is safe to be released to the environment. We are developing a plan to remove toxic waste from water so it is safe to be discharged to watersheds and local communities. 

More about Environmental Engineering at UBC

Our project’s future

The federal government is currently managing the site and has a treatment plan in place. We may decide to send our final report and recommendations to the group currently overseeing the project

 
UBC environmental engineering students taking a reading in an urban creek.

Environmental Engineering

As one of the most beautiful places anywhere, British Columbia is an ideal location to pursue an Environmental Engineering degree. UBC offers two Environmental Engineering Programs...

Environmental Engineering

Discover Student Experiences

UBC Applied Science students are people who are passionate about their chosen field — architecture, landscape architecture, community and regional planning, engineering and nursing — and those that inspire others by making meaningful contributions to the betterment of society.

Browse Student and Alumni Spotlights
UBC Crest The official logo of the University of British Columbia. Arrow An arrow indicating direction. Arrow in Circle An arrow indicating direction. Caret An arrowhead indicating direction. E-commerce Cart A shopping cart. Time A clock. Chats Two speech clouds. Facebook The logo for the Facebook social media service. Home A house in silhouette. Information The letter 'i' in a circle. Calendar Location Instagram The logo for the Instagram social media service. Linkedin The logo for the LinkedIn social media service. Social Media The globe is the default icon for a social media platform. TikTok The logo for the TikTok social media platform. Location Pin A map location pin. Mail An envelope. Telephone An antique telephone. Play A media play button. Search A magnifying glass. Arrow indicating share action A directional arrow. Speech Bubble A speech bubble. Star An outline of a star. Twitter The logo for the Twitter social media service. Urgent Message An exclamation mark in a speech bubble. User A silhouette of a person. Vimeo The logo for the Vimeo video sharing service. Youtube The logo for the YouTube video sharing service. Future of work A logo for the Future of Work category. Inclusive leadership A logo for the Inclusive leadership category. Planetary health A logo for the Planetary health category. Solutions for people A logo for the Solutions for people category. Thriving cities A logo for the Thriving cities category. University for future A logo for the University for future category.