The Giant Gold Mine Remediation in the Northwest Territories, near Yellowknife

After a very interesting student presentation on heavy metal pollution in our BIOL4095 class, I thought I should share my own experience visiting  the Giant Mine remediation site in Northwest Territories.

Giant Mine, NWT.  Photo by Dmitri Perlov.

Giant Mine, NWT. Photo by Dmitri Perlov.

The Giant Mine was a large gold mine located just outside of Yellowknife, NWT. The mine entered production in 1948 and ceased operation in 2004. Over its time of operation, the mine produced 220,000 kg of gold. But the gold smelting process produced 237,000 tons of Arsenic (As) trioxide dust, a highly dangerous inorganic compound and a well known carcinogen. This makes Giant Mine the worst contaminated site in Canada.

Giant Mine Grate Slave lake shore with Yellowknife on the horizon. Photo by Dmitri Perlov.

Giant Mine along the Great Slave lake shore with Yellowknife on the horizon. Photo by Dmitri Perlov.

Currently the remediation work is composed of: (1) freezing the 237,000 tons of As using the frozen block method; (2) cleaning up tailing ponds and surrounding soil, including Baker Creek and eight open pits; (3) water clean-up and release into Baker Creek which flows into Grate Slave Lake; and (4) revitalizing the surrounding vegetation. This remediation project will cost Canadian tax payers $1-billion.

For more information on the Giant Mine remediation project here.

The Giant Mine Freeze Block Method Used to immobilize Arsenic trioxide dust in underground chambers.

The Giant Mine Freeze Block Method Used to immobilize Arsenic trioxide dust in underground chambers.

 

Thermosiphon used for passive cooling of the underground frozen block at Giant Mine. Photo by Dmitri Perlov.

Thermosiphon used for passive cooling of the underground frozen block at Giant Mine. Photo by Dmitri Perlov.

Giant Mine Frozen Block Method. Active cooling of Arsenic chambers 80 meters below ground.

Giant Mine Frozen Block Method. Active cooling of Arsenic chambers 80 meters below ground.

Giant Mine tailings. There are 8 open pits, 4 tailing ponds and over 325,000 cubic meters of contaminated soil. Photo by Dmitri Perlov.

Giant Mine tailings. There are 8 open pits, 4 tailing ponds and over 325,000 cubic meters of contaminated soil. Photo by Dmitri Perlov.

 

 

Giant Mine water treatment using Fe(III) co-precipitation. The observed oragen/deep red colour is the As-Fe co-precipitate. Photo by Dmitri Perlov.

Giant Mine water treatment using Fe(III) co-precipitation. The observed oragen/deep red colour is the As-Fe co-precipitate. Photo by Dmitri Perlov.

However, there seemed to be a somewhat flawed approach to remediation work currently undertaken by the Canadian government, as they are dealing with restoring the environment but do not have a single biologist on the remediation team. Although land and water treatment and As removal has proven to be successful. There is, however, an apparent issue with revitalizing the site’s vegetation.

During the tour of the Giant Mine, the remediation manager explained that vegetation restoration consisted of spread of a mixture of seeds of plants, both local and from the South (BC and Alberta). But in my opinion, this raises issues dealing with the introduction of foreign species into the environment which may become invasive, especially in the face of rapid warming climate in the North.

The lab I am working in at Laurier university is looking at different plants from contaminated regions near  the Giant Mine including Black Creek, and comparing their growth to soil unaffected by As contamination. Helping a graduate student, I had the first hand chance to see the effects of As on these plants: plants growing in soil with high As concentrations had severely reduced growth rates compared to plants growing in lower As concentrations. Even more interestingly, plants growing in high As concentration produced red leaves, compared to green leaves produced under low As concentrations.

 

For more information on Giant Mine and the remediation project read  The EconomistCBC, and Global News.

Day 06 (40)Day 06 (31)

Advertisements
This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s