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Events/Disaster · 2014

Mount Polley tailings dam breach

Disaster, 4 August 2014, Canada.

What happened

The tailings storage facility breached on 4 August 2014. The independent panel reported on 30 January 2015 and found a weak glaciolacustrine layer in the foundation. About 10 million cubic metres of water was in the pool at failure.1,2

Why it matters

The panel reported on 30 January 2015 and made recommendations to reduce the chance of tailings failures.1,2

Story cards

Around the same time

  1. Panguna mine halted

    The closure became tied to the Bougainville conflict.3,4

  2. Privatisation of ZCCM weakens TAZARA's copper traffic

    More copper then went by road along southern routes and the Tanzam highway.5,6

  3. Northparkes block cave air blast

    Northparkes was the first block caving mine in Australia, and the Coroner's findings shaped how block caving is regulated there.7,8

  4. Falun Great Copper Mountain inscribed

    UNESCO World Heritage listing event.9

  5. Berkeley Pit cleanup settlement

    The EPA called it the nation's largest body of contaminated water.10,11

  6. Copiapo mining accident (33 miners trapped)

    Copiapo mining accident (33 miners trapped). Wikidata records 0 deaths.12

  7. Manefay landslides at Bingham Canyon

    UGS says Kennecott had a sophisticated network of geotechnical monitors in place.13,14

  8. Angola awards a 30-year Benguela Railway concession

    The Lobito Atlantic Railway consortium took over the Angolan line (some sources date the award to 2023).15,16

Open the full timeline

Where next

Events

An example ofFundao tailings dam collapse at MarianaFifteen months after Mount Polley, the Fundao dam failed in Brazil, killing 19.17ExamplesBrumadinho dam collapseTailings failures on two continents: Mount Polley in 2014 killed no one, Brumadinho 270.1

Sources

  1. Final report media release (30 Jan 2015) and report PDF Mount Polley Independent Expert Engineering Investigation and Review Panel
  2. Mount Polley mine (item Q107703678), coordinate location P625 Wikidata
  3. History: Panguna Mine Bougainville Copper Limited
  4. Panguna mine (item Q17060798), coordinate location P625 Wikidata
  5. 'Win-win' contested: negotiating the privatisation of Africa's Freedom Railway with the 'Chinese of today' Journal of Modern African Studies 59(1) (Cambridge University Press)
  6. Wikidata item Q239580 (Kitwe)
  7. 1999 Northparkes Air Blast case study (Learning from disasters) NSW Resources Regulator
  8. Parkes (item Q605513), coordinate location P625 Wikidata
  9. Mining Area of the Great Copper Mountain in Falun UNESCO World Heritage Centre
  10. US and Montana reach agreement with mining companies to clean up Berkeley Pit (25 Mar 2002) US Environmental Protection Agency
  11. Berkeley Pit (item Q820869), coordinate location P625 Wikidata
  12. Wikidata item Q214790 (Copiapo mining accident (33 miners trapped))
  13. Bingham Canyon's Manefay Landslides and the Future of the Mine Utah Geological Survey
  14. Bingham Canyon Mine (item Q2450901), coordinate location P625 Wikidata
  15. From Transit to Transformation: Leveraging the Lobito Corridor (Angola Economic Update) World Bank
  16. Wikidata item Q223914 (Lobito)
  17. London judge rules BHP liable for 2015 Brazil dam collapse (14 Nov 2025) The Guardian

From the Prospector Trails mining history dataset: each fact links to the source it was checked against. Figures are as the source gives them, in the money of their day. Not investment advice.

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Cover photos from Wikimedia Commons: Haul trucks by Lechhabmed, CC BY-SA 4.0. Pictures: Kimberley, South Africa: miners and washing gear at the Bultfontein diamond mine. Woodburytype, 1888, after a photograph by Robert Harris., Harris, Robert, active 1881-1888. (Public Domain Mark 1.0); Earth Observations taken by the Expedition 15 Crew, NASA JSC (Public domain (NASA media, no copyright)).