Giant Mine Historical Timeline

Timeline of important dates in the Giant Mine site's history from 1935 until the conclusion of the Environmental Assessment Process.

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• What's happening at Giant Mine?

For more information about work after 2014, please see Risks addressed to date.

2014

• The final five Roaster Complex buildings are deconstructed.

• The real-time Air Quality Monitoring program is implemented.

• The Report of Environmental Assessment and Reasons for Decision for the Giant Mine Remediation Project is released, which outlines 26 measures for the Project Team to complete before remediation can proceed.

2013

• The Giant Mine Remediation Project team (Project team) proposes to treat mine water to drinking water standards.
• Mackenzie Valley Land and Water Board issues water licence for the Site Stabilization Plan.
• Work begins on Roaster decontamination and deconstruction.

2012

• A second round of Information Requests completed as part of the Environmental Assessment.
• Public meetings in Ndilo, Dettah, and Yellowknife are held to discuss urgent work required at the site.
• The Project team applies for and receives Land Use Permit MV2012S0019 for geotechnical drilling.
• The Mackenzie Valley Environmental Impact Review Board (Review Board) holds public hearings as part of Environmental Assessment.
• The Review Board public registry closes.
• The Project team applies to Mackenzie Valley Land and Water Board (Land and Water Board) for water licence (MV2012L8-0010) for urgent work on site (see Site Stabilization Plan).

2011

• The first round of Information Requests is completed as part of the Environmental Assessment.
• The freeze optimization study becomes operational.
• The Land and Water Board and Government of the Northwest Territories (GNWT) Department of Municipal and Community Affairs issue a Joint Determination on regulation of land use within City of Yellowknife.
• The Review Board holds technical sessions as part of the Environmental Assessment.
• The Project team removes cladding from C-shaft headframe and takes down the conveyor gallery for safety reasons.

2010

• A series of public meetings are held to discuss the components of the Remediation Plan and their possible impacts on the environment.
• The Project team submits Developer's Assessment Report to the Review Board.

2009

• The Review Board releases Terms of Reference for the Environmental Assessment.
• Construction begins on the Freeze Optimization Study.

2008

• The Land and Water Board releases the "Preliminary Screening: Reasons for Decisions". It concludes that the Remediation Plan is not likely to be a cause of adverse environmental impact or public concern.
• The City of Yellowknife refers project to environmental assessment under s.126(2)(d) of the Mackenzie Valley Resource Management Act. The City cites potential adverse environmental impact within municipal boundaries.
• The Review Board initiates an Environmental Assessment.

2007

• Indigenous and Northern Affairs Canada (INAC) submits the Remediation Plan, along with a water licence application, to the Land and Water Board.
• Deton' Cho Nuna Joint Venture is awarded a multi-year contract for care and maintenance at Giant Mine.

2006

• A Remediation Plan for the immediate and long-term cleanup of the mine is developed by INAC's technical advisors. It is reviewed by independent experts.

2005

• INAC and the GNWT sign a Cooperation Agreement to work together on surface and subsurface remediation of Giant Mine.
• Miramar terminates its obligations under the Reclamation Security Agreement. Giant Mine officially becomes an abandoned mine site.
• Deton' Cho Nuna Joint Venture wins a contract to assume responsibility for interim care and maintenance of Giant Mine.

2004

• INAC announces the decision to proceed with the Frozen Block Method as the preferred long-term management alternative for storage of arsenic trioxide dust.

2003

• The Independent Peer Review Panel tables its review of the technical advisor's final report.
• The technical advisor tables its final report "Arsenic Trioxide Management Alternatives – Giant Mine" at a public workshop in January.
• INAC initiates extensive public communications campaign regarding management alternatives for Giant Mine.
• The Giant Mine Community Alliance is established and holds its first meeting.
• The Project team hosts a workshop in May.
• INAC seeks approval to proceed with project description.

2002

• INAC and community stakeholders appoint an Independent Peer Review Panel to assess options for long-term management of arsenic trioxide dust.
• A Tier 2 human health and ecological risk assessments is conducted to assess risks of current arsenic releases from the mine site. It also assesses potential future releases under various arsenic trioxide management alternatives.
• Field testing of a deep thermosyphon is initiated.

2001

• The technical advisor completes the report "Study of Management Alternatives – Giant Mine Arsenic Trioxide Dust".
• A public technical workshop is held to review the report.
• Remediation work is completed on the former Back Bay tailings beach.
• Miramar Giant Mine Ltd. submits an abandonment and restoration plan to the Land and Water Board.

2000

• SRK Consulting wins an international competition to become the lead technical advisor to INAC on the management of arsenic trioxide dust.

1999

• Royal Oak Mines goes into receivership. Giant Mine is transferred INAC.
• INAC starts work on an action plan to manage arsenic trioxide dust stored underground.
• INAC sells Giant Mine assets to Miramar Giant Mine Ltd., a division of Miramar Mining Corporation.
• INAC becomes caretaker for pre-existing environmental liabilities on the property. This includes arsenic trioxide dust stored underground.

1997

• INAC, along with Royal Oak Mines, Environment Canada, the GNWT, and the City of Yellowknife co-host a technical workshop to discuss managing the arsenic trioxide at Giant Mine.

1992

• An explosion, deliberately-set, during a labour strike results in deaths of nine miners.

1991

• Royal Oak Mines Inc. is formed.

1990

• Royal Oak Resources Ltd. gains control of Giant Yellowknife Gold Mines Ltd.

1987

• The Northwest Tailings Pond is built to accommodate re-processed tailings.

1981-1986

• Koppers Corp. of Georgia, U.S.A. purchases 6,700 tonnes of arsenic trioxide dust from Giant Mine to treat wood. The price drops, ending Koppers Corp.'s purchases.
• Regular inspection of the storage chambers begins.

1981

• The new tailings effluent treatment plant begins operating.

1974

• Open pit mining begins.

1970

• The Commissioner's Lands Act proclaims surface land transfers to the NWT, including Giant Mine site.

1967

• An improved tailings effluent treatment circuit is commissioned.

1962

• Arsenic trioxide storage moves to mined-out stopes located in permafrost.

1959

• Airborne arsenic emissions drop to 200 to 300 kg/day. Some is as low as 52 kg/day.

1958

• The mill processing rate increases to 1,000 tonnes per day.
• The Dracco baghouse facility is constructed to collect arsenic trioxide dust

1957

• Tailings Dam #2 is built.
• Arsenic removal from tailings effluent starts.

1955

• A Hot Cottrell Electrostatic Precipitator is installed to capture gold-bearing arsenic dust.

1953

• Tailings dam construction marks beginning of engineered tailings disposal.

1952

• The mill processes 400 to 700 tonnes of ore per day.

1951

• A Cold Cottrell Electrostatic Precipitator is installed to remove arsenic trioxide from roaster gasses.
• Arsenic emissions drop to 5,500 kg/day.
• Arsenic trioxide dust is pumped into mined-out storage chambers 80-250 feet below surface. The chambers are in permafrost.

1950

• Giant Yellowknife Gold Mines initiates first studies into arsenic in the surrounding environment. This leads to revised operations

1949-1951

• Airborne arsenic emissions estimated at 7,500 kg/day.

1948

• June 3, the first gold brick is poured.
• Tailings are deposited into Back Bay.

1937

• Yellowknife Gold Mines Ltd. acquires Burwash's assets. These become part of a subsidiary – Giant Yellowknife Gold Mines Ltd.

1935

• Burwash Yellowknife Mines Ltd. stakes 21 claims, including the future Giant Mine.