Yellowknife gold mine and arsenic pollution, Canada

The gold Giant Mine in the Yellowknife region operated from 1948 to 1999, releasing 237,000 tonnes of waste arsenic trioxide dust from ore extraction and roasting processes.


Gold was first discovered by prospectors in the Yellowknife area in 1896, who were headed north for Klondike riches. Nothing came of the Yellowknife discovery at the time. The area was considered inaccessible. However, after 1935 and the arrival of commercial aircraft (bush planes) the area became more accessible, and the gold boom began.  In the summer of 1935, C.J. "Johnny" Baker and H. Muir staked the original 21 "Giant" claims for Bear Exploration Company. . By 1937, Giant Yellowknife Gold Mines Ltd was created. The company fell on hard times and by 1940, operations came to a standstill. Further, the advent of World War II  meant a shortage of men to work the site. Soon after the war ended, Giant Mine officially opened, and production moved into full swing. The first gold brick was poured on June 3, 1948.[1]

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Basic Data
NameYellowknife gold mine and arsenic pollution, Canada
ProvinceNorthwest Territories
Accuracy of LocationMEDIUM regional level
Source of Conflict
Type of Conflict (1st level)Mineral Ores and Building Materials Extraction
Type of Conflict (2nd level)Mineral processing
Specific CommoditiesGold
Project Details and Actors
Project DetailsThe remediation project. The Giant Mine produced seven million ounces of gold in fifty years; however, it also left a legacy of contamination and environmental liabilities. Proponents of the Giant Mine Remediation Project aim to freeze 237,000 tonnes of arsenic trioxide dust stored in chambers under the mine in Yellowknife, N.W.T. in order to keep it from contaminating nearby water [5]. This would be a nearly $1-billion project. The arsenic dust being stored underground is dangerous. It is alleged that in in 1951, when the mine wasn't regulated, a boy with the Yellowknives Dene First Nation died after eating some snow near the site. Presence of arsenic in local lakes [6] and in local small animals [7] has been proven, and there is research on presence of arsenic in human bodies also [8). There is also methyl mercury in neighbouring lakes [9].[10].

In June 2018 the government published a map of lakes in the area. A number of them marked with orange, red or purple, meaning that “Arsenic levels are elevated (52 parts per billion and above). Water should not be consumed from these lakes. It is also recommended to avoid fishing, swimming, and harvesting berries, mushrooms and other edible plants within this zone. However, walking through this area does not pose a health hazard.” [6].

The dust was a by-product of gold extraction that occurred at the mine from 1948 onwards. It resulted in an arsenic-rich gas that was captured as dust and stored in underground chambers. The mine's operators hoped that permafrost would trap the arsenic underground, but some of that frost has thawed leaving water to seep in and out of some of the underground chambers. [5]. The federal government took over the mine in 1999, and when the frost didn't materialize, a group including the federal, provincial and Yellowknife city governments resolved to create an "impenetrable barrier" using a "frozen block process" that keeps the ground frozen. [5].
Level of Investment (in USD)1,000,000,000
Type of PopulationRural
Potential Affected Population19,000
Start Date1999
Company Names or State EnterprisesRoyal Oak Mine Corp from Canada
Relevant government actorsIndigenous and Northern Affairs Canada.

Environment Canada.

Government of the Northwest Territories.

City of Yellowknife.
Environmental justice organisations and other supportersYellowknives Dene
The Conflict and the Mobilization
Intensity of Conflict (at highest level)MEDIUM (street protests, visible mobilization)
When did the mobilization beginMobilization for reparations once impacts have been felt
Groups MobilizingIndigenous groups or traditional communities
Trade unions
Ethnically/racially discriminated groups
Local scientists/professionals
Yellowknives Dene First Nation
Forms of MobilizationCreation of alternative reports/knowledge
Lawsuits, court cases, judicial activism
Media based activism/alternative media
Official complaint letters and petitions
Appeals/recourse to economic valuation of the environment
Environmental ImpactsVisible: Air pollution, Soil contamination, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion, Mine tailing spills, Other Environmental impacts
Potential: Loss of landscape/aesthetic degradation, Waste overflow
OtherArsenic contamination
Health ImpactsVisible: Occupational disease and accidents, Deaths
Potential: Exposure to unknown or uncertain complex risks (radiation, etc…)
Socio-economic ImpactsVisible: Violations of human rights, Land dispossession
Potential: Lack of work security, labour absenteeism, firings, unemployment, Loss of traditional knowledge/practices/cultures, Loss of landscape/sense of place
OtherViolation of human right to health. Violation of indigenous territorial rights.
Project StatusStopped
Pathways for conflict outcome / responseCompensation
Court decision (failure for environmental justice)
Under negotiation
Do you consider this as a success?No
Why? Explain briefly.The gold Giant Mine stopped working many years ago and by 2018 no compensation has been paid (to local inhabitants, and to workers) from contamination by arsenic. The remediation plans are expensive (and to be paid for by taxpayers). A case of very large environmental liabilities, unpaid for..
Sources and Materials


[9] PLOS ONE. Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife, NT, (Canada) Region. By Adam James Houben , Rebecca D’Onofrio, Steven V Kokelj, Jules M Blais, April 6, 2016, Abstract: Gold mines in the Yellowknife, NT, region—in particular, the Giant Mine—operated from 1949–99, releasing 237,000 tonnes of waste arsenic trioxide (As2O3) dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing ...

[7] Sci Total Environ. 2018 Mar 15;618:916-926. doi: 10.1016/j.scitotenv.2017.08.278. Chronic arsenicosis and cadmium exposure in wild snowshoe hares (Lepus americanus) breeding near Yellowknife, Northwest Territories (Canada), part 1: Evaluation of oxidative stress, antioxidant activities and hepatic damage. By Amuno S, Jamwal A, Grahn B, Niyogi S. Abstract. Previous gold mining activities and arsenopyrite ore roasting activities at the Giant mine site (1948 to 2004) resulted in the release of high amounts of arsenic and trace metals into the terrestrial and aquatic ecosystems of Yellowknife, Northwest Territories, Canada. While elevated levels of arsenic has been consistently reported in surface soils and vegetation near the vicinity of the Giant mine area and in surrounding locations, systematic studies evaluating the overall health status of terrestrial small mammals endemic to the area are lacking...

[11] Canadian Working-Class Environmentalism,1965–1985. By Katrin MacPhee. J of Canadian Labor Studies, 2004, vol. 74.
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Description of history of the city of Yellowknife. Canadian Encyclopedia.
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[10] Lakes near Yellowknife contaminated with arsenic, mercury years after mine closing, Globe and Mail, Ivan Semeniuk, May 16, 2018.
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[2] Yellowknife, on the murder of workers by a bomb in 1992, meant to frighten scabs and the company during a lockout. Canadian Encyclopedia.
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[3] Description of the production of gold by Giant Mine worth over 2 billion dollars along many years and also of the contamination by arsenic. Global News Canada.
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[4] Good description of the contamination, damage to people by arsenic.
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[5] HuffPost Canada, 04/17/2014 Yellowknife Mine Sits Atop A Lethal Store Of Arsenic
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[1] History of Gian Mine
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[6]Arsenic in Lake Water Around Yellowknife. (June 15, 2018) – The NWT Chief Public Health Officer is updating the advice provided to residents and visitors about precautions they can take to avoid exposure to elevated arsenic levels found in some of the lakes located around Yellowknife.
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[8] Toenails, saliva and urine could answer questions about Giant Mine's toxic legacy. 200 people from Yellowknife, Dettah and Ndilo are giving toenail, urine, saliva samples to test for arsenic. Kate Kyle · CBC News · Nov 07, 2017
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Media Links

Examining the history of arsenic contamination at Giant Mine in Canada’s Northwest Territories. A partnership among researchers at Memorial University, Lakehead University, the Goyatiko Language Society (a Yellowknives Dene First Nation non-profit), and Alternatives North (a Yellowknife environmental and social justice coalition).
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Documentary, Freezing 200,000 Tons of Lethal Arsenic Dust, T. Scott.
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Other Documents

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Source: Globe and Mail
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Meta Information
ContributorPol.Ecol. Students Vancouver and JMA
Last update18/11/2018