Diavik Diamond Mine — Production, History & Operations on Lac de Gras

An Island Mine in the Arctic

Few diamond mines in the world are as visually striking as Diavik. Situated on a 20-square-kilometre island in Lac de Gras — a large, remote lake approximately 300 kilometres northeast of Yellowknife in the Northwest Territories — the Diavik mine is an engineering marvel set against the stark beauty of the Canadian Arctic. The mine's open pits, carved into the island's bedrock and extending below the surrounding lake level, required the construction of massive dikes to hold back the waters of Lac de Gras, making Diavik one of the most technically challenging mining operations ever undertaken in Canada.

Operated by Rio Tinto, Diavik began production in January 2003 and quickly established itself as one of the most productive and valuable diamond mines on the planet. Over its two-decade operational life, the mine produced an estimated 124 million carats of rough diamonds with a cumulative value exceeding US$18 billion. The mine's high proportion of gem-quality stones — many grading in the colourless to near-colourless range — made Diavik diamonds among the most sought-after in the global market.

With mining operations concluding in 2025, Diavik is now entering its closure and reclamation phase — a carefully planned process that will ultimately return the island to a state compatible with the surrounding environment and traditional land use.

Discovery and Development

The kimberlite pipes at Diavik were discovered during the exploration frenzy that followed Chuck Fipke's landmark discovery at nearby Ekati in 1991. Aber Resources (later renamed Aber Diamond Corporation, and eventually Harry Winston Diamond Corporation and then Dominion Diamond) staked claims on the small island in Lac de Gras and identified four kimberlite pipes through systematic exploration drilling in the mid-1990s.

The development decision was made by Diavik Diamond Mines Inc. — a joint venture between Rio Tinto (60%) and Aber Resources (40%) — following a comprehensive feasibility study and environmental assessment. Construction began in 2001, with the project facing significant logistical challenges: all materials and equipment had to be transported either by air or via the seasonal Tibbitt to Contwoyto Winter Road, and the mine's island location required engineered dikes to allow open-pit mining below the lake surface.

The construction phase employed over 1,600 workers at peak and cost approximately CAD $1.3 billion. The first diamonds were recovered in January 2003, ahead of schedule, and the mine reached full production capacity within its first year of operations.

Kimberlite Pipes and Geology

Diavik's diamond resources are contained within four kimberlite pipes, all located on or immediately adjacent to the small island in Lac de Gras. Each pipe has its own geological characteristics and mining history:

The kimberlite at Diavik is classified as Group 1 kimberlite — the most common type associated with diamond deposits worldwide. The pipes intruded through Archean granite and metasedimentary rocks of the Slave Craton approximately 55 million years ago during the Eocene epoch. The diamonds themselves, however, are far older, having crystallised in the Earth's mantle between 1 and 3.5 billion years ago before being transported to the surface by the kimberlite eruptions.

One of Diavik's geological advantages is the relatively high diamond content per tonne of kimberlite processed. The mine's ore grade has averaged between 2.5 and 4.0 carats per tonne across its various pipes — significantly higher than many other diamond operations globally. Combined with the high average value per carat, this grade made Diavik one of the most economically productive diamond mines in the world on a per-tonne basis.

Production Data and Output

Diavik's production record reflects a mine that consistently delivered high volumes of valuable rough diamonds across more than two decades of operations:

Diavik's lifetime production of approximately 124 million carats places it among the top-producing diamond mines globally. The average value of Diavik diamonds has ranged from US$100 to over US$200 per carat depending on market conditions and the mix of ore processed, with peak per-carat values recorded during the strong diamond market of 2011 and again in 2022. Notably, Diavik has produced several exceptional stones over its lifetime, including rough diamonds exceeding 100 carats — rare finds that generate significant attention in the international diamond trade.

The Diavik Wind Farm: Arctic Renewable Energy

In September 2012, Diavik commissioned a 9.2-megawatt wind farm — one of the most northerly large-scale wind energy installations in the world. The project consists of four Enercon E-70 wind turbines, each with a rated capacity of 2.3 megawatts, specifically engineered for Arctic conditions including extreme cold, high winds, and ice buildup.

The wind farm was designed to reduce Diavik's dependence on diesel fuel, which constitutes the mine's primary energy source and must be transported in via the winter road at considerable cost. At full capacity, the turbines offset approximately 10% of the mine's total energy consumption and reduce diesel usage by an estimated 3.8 million litres per year, cutting annual CO2 emissions by roughly 12,000 tonnes.

Rio Tinto Ownership and Operations

Rio Tinto has been the operator of the Diavik mine since its inception. As one of the world's largest mining companies, Rio Tinto brought substantial capital, technical expertise, and operational systems to the Diavik project. The company's diamonds division managed Diavik alongside its other diamond operations, including the Argyle mine in Western Australia (which closed in 2020 after nearly four decades of production).

The ownership structure of Diavik evolved over the mine's life. Originally a 60/40 joint venture between Rio Tinto and Aber Resources, the minority stake changed hands as Aber was renamed Harry Winston Diamond Corporation (2007) and then Dominion Diamond Corporation (2013). When Dominion entered creditor protection in 2020, Rio Tinto acquired the remaining 40% interest in 2021, becoming the sole owner of the mine for its final years of production and the closure process.

Rio Tinto's operational management of Diavik has been characterised by a strong emphasis on safety performance, environmental compliance, and community engagement. The mine has received multiple industry awards for safety and has maintained rigorous environmental monitoring programs throughout its operational life.

Employment, Training, and Northern Participation

At peak operations, Diavik employed approximately 1,100 to 1,200 workers, with roughly 700 present on-site at any given time. The mine operates on a fly-in, fly-out rotation, with most workers spending two weeks at the mine followed by two weeks at home. A dedicated camp facility on the island provides accommodation, dining, recreation, and medical services.

Northern participation in the Diavik workforce has been a central pillar of the mine's social commitments. Approximately 50% of Diavik's employees have been Northern residents, with Indigenous workers representing a significant and growing share of the workforce. Rio Tinto has invested in training programs, apprenticeships, and partnerships with Northern educational institutions to build skills and capacity in local communities. These investments have created a skilled workforce that extends well beyond diamond mining, with former Diavik employees working across the Northern economy in construction, heavy equipment operation, environmental monitoring, and other fields.

The mine holds participation agreements with five Indigenous communities and organisations, ensuring that economic benefits flow to the communities most directly affected by mining operations. Over the mine's lifetime, billions of dollars in contracts have been awarded to Northern and Indigenous-owned businesses for services ranging from catering and camp management to equipment maintenance and environmental consulting.

Closure and Reclamation

With diamond production concluding in 2025, Diavik is entering one of the most closely watched mine closure processes in Canadian history. The closure plan, developed in consultation with Indigenous communities, regulators, and environmental experts, is expected to take approximately 10 years or more to complete and involves multiple complex phases:

• Infrastructure removal: All surface buildings, processing equipment, and non-essential infrastructure will be dismantled and removed from the site. Materials will be recycled where possible and hazardous materials disposed of at approved facilities.
• Dike management: The engineered dikes that held back Lac de Gras water to enable open-pit mining will be breached in a controlled manner, allowing the lake to refill the pits over time. This process will be carefully monitored to ensure water quality standards are maintained.
• Processed kimberlite containment: The Processed Kimberlite Containment (PKC) facility, which holds tailings from the ore processing plant, will be stabilised and capped. Long-term monitoring will ensure that any seepage meets water quality standards.
• Waste rock management: Waste rock piles will be reshaped and covered to promote revegetation and minimise acid rock drainage. Some waste rock has already been used for construction during the operational phase, reducing the volume requiring management at closure.
• Long-term monitoring: Rio Tinto has committed to multi-decade environmental monitoring of water quality, wildlife activity, vegetation recovery, and permafrost stability at the Diavik site. Monitoring data will be shared with Indigenous communities and regulators.

Rio Tinto has allocated over CAD $1 billion to the Diavik closure fund, making it one of the largest mine reclamation commitments in Canadian history. The closure plan is designed to return the island to a condition that supports traditional land use, wildlife habitat, and a self-sustaining ecosystem — a goal that reflects both regulatory requirements and the expectations of the Indigenous communities who have inhabited this landscape for millennia.

Diavik's Place in Canadian Diamond History

Diavik occupies a unique position in the story of Canadian diamond mining. As the second major diamond mine to open in the Northwest Territories — five years after Ekati — Diavik confirmed that the Lac de Gras region was not a one-mine anomaly but a world-class diamond district. Together with Ekati and the later Gahcho Kué mine, Diavik helped establish Canada as a consistent top-five global diamond producer by both volume and value.

The mine's island setting made it one of the most photographed and recognisable mines in the world, with aerial images of its open pits surrounded by the deep blue waters of Lac de Gras featured in countless documentaries, publications, and educational materials. Beyond its visual impact, Diavik's operational innovations — including the Arctic wind farm, the engineered dikes, and the progressive reclamation program — have set standards that influence mining practice globally.

For the communities of the Northwest Territories, Diavik has been a transformative economic force. The mine has contributed billions of dollars in wages, taxes, royalties, and procurement spending to the territorial and national economies, while its training and employment programs have built human capital that will serve Northern communities long after the last diamond has been recovered.

Learn more about Canada's diamond mining landscape on our interactive mines map, or explore the full scope of the industry in our Canadian diamond industry report.

Frequently Asked Questions About the Diavik Diamond Mine