Tailings dam failure explained

The structural failure of tailings dams and the ensuing release of toxic metals in the environment is a great concern. The standard of public reporting on tailings dam incidents is poor. A large number remain completely unreported, or lack basic facts when reported. There is no comprehensive database for historic failures.[1] According to mining engineer David M Chambers of the Center for Science in Public Participation, 10,000 years is "a conservative estimate" of how long most tailings dams will need to maintain structural integrity.[2]

Rate

The lack of any comprehensive tailings dam database has prevented meaningful analysis, either gross comparisons (such as country to country comparisons, or tailings dam failures versus hydro dam failure rates) or technical failure analysis to help prevent future incidents. The records are very incomplete on crucial data elements: design height of dam, design footprint, construction type (upstream, downstream, center line), age, design life, construction status, ownership status, capacity, release volume, runout, etc.

An interdisciplinary research report from 2015 recompiled the official global record on tailings dam failures and major incidents and offered a framework for examining the severity and consequence of major incidents. That report shows a correlation between failure rates and the pace of copper ore production, and also establishes a relationship between the pursuit of lower grades of ore, which produces larger volumes of waste, and increasingly severe incidents.[3] [4] For this reason, several programs to make tailing dams more sustainable have been set in motion in countries like Chile, where there are more than 740 spread across the country.[5]

Environmental damage

The mining and processing byproducts collected in tailings dams are not part of the aerobic ecological systems, and are unstable. They may damage the environment by releasing toxic metals (arsenic and mercury among others), by acid drainage (usually by microbial action on sulfide ores), or by damaging aquatic wildlife that rely on clear water.[6]

Tailings dam failures involving significant ecological damage include:

Tailings ponds can also be a source of acid drainage, leading to the need for permanent monitoring and treatment of water passing through the tailings dam. For instance in 1994 the operators of the Olympic Dam mine, Western Mining Corporation, admitted that their uranium tailings containment had released of up to 5 million m3 of contaminated water into the subsoil.[21] The cost of mine cleanup has typically been 10 times that of mining industry estimates when acid drainage was involved.[22]

Casualties

The following table of the deadliest known tailings dam failures is not comprehensive, and the casualty figures are estimates.

Dam/incidentYearLocationFatalitiesDetails
1962 Huogudu(火谷都), China tailing pond failure data-sort-value="1962-09-26" 26 September 1962Huogudu (火谷都), Gejiu， Yunnan, China 171Few details available. A tailings pond at a tin mine operated by Yunnan Tin Group collapsed. 368M m3 surged. One source reports 171 killed and another 92 injured; another has the date as 26 September.[23] [24]
Mina Plakalnitsadata-sort-value="1966-05-01" 1 May 1966Vratsa, Bulgariadata-sort-value="480" 480+A tailings dam at Plakalnitsa copper mine near the city of Vratsa failed. A total 450,000 cu m of mud and water inundated Vratsa and the nearby village of Zgorigrad, which suffered widespread damage. The official death toll is 107, but the unofficial estimate was more than 480.[25]
Certej dam failuredata-sort-value="1971-10-30" 30 October 1971Certej Mine, Romania89A tailings dam built too tall collapsed, flooding Certeju de Sus with toxic tailings.[26]
Buffalo Creek Flooddata-sort-value="1972-02-26" 26 February 1972West Virginia, United States125Unstable loose constructed dam created by local coal mining company, collapsed in heavy rain. 1,121 injured, 507 houses destroyed, over 4,000 left homeless.
Val di Stava damdata-sort-value="1985-07-18" 19 July 1985Tesero, Italy268Poor maintenance and low margin for error in design; outlet pipes failed, leading to pressure on dam and sudden collapse. Ten people were ultimately convicted of manslaughter and other charges.
Mufuliradata-sort-value="1970" 1970Zambia89A tailings reservoir breached and collapsed into the copper mine below it, killing 89 night-shift workers.[27]
Aberfan disasterdata-sort-value="1966-10-21" 21 October 1966Wales144The collapse and landslide of a spoil tip accumulated above the mining town on geologically unstable ground killed 28 adults and 116 children (not an engineered structure)
data-sort-value="2015-10-25" 25 October 2015113A slag heap reportedly used by multiple operators in this jade-mining region became unstable and flooded into nearby residences (not an engineered structure)[28]
El Cobre landslidedata-sort-value="1965-03-28" 28 March 1965Chile300Shaking from a magnitude 7.4 earthquake caused the failure of two tailings dams at the El Soldado copper mine. The resulting flow destroyed the town of El Cobre.
data-sort-value="1994-02-22" 22 February 1994Virginia, Free State, South Africa 17Merriespruit tailings dam overtopped in heavy rains. The flow of an estimated 600,000 m3 (1.2 Million tonnes) of tailings reached the town of Merriespruit 2 kilometers away. With the seventeen fatal casualties, dozens of homes were engulfed.[29]
Taoshi landslidedata-sort-value="2008-09-08" 8 September 2008Linfen, Shanxi, Chinadata-sort-value="254" 254+Iron mine tailings, formerly administered by the state and then put into private hands, collapsed into a village at 8 am.[30]
Bento Rodrigues dam disasterdata-sort-value="2015-11-05" 5 November 2015Mariana, Minas Gerais, Brazil19A tailings dam at an iron ore mine jointly owned by Vale S.A. and BHP and suffered a catastrophic failure releasing around 60 million cubic meters of iron waste into the Doce River which reached the Atlantic Ocean.
Brumadinho dam disasterdata-sort-value="2019-01-25" 25 January 2019Brumadinho, Minas Gerais, Brazildata-sort-value="186" 259+[31] A tailings dam at an iron ore mine operated by Vale S.A. suffered a catastrophic failure.[32]

Largest

The following list focuses on the largest tailings dam failures:

Name Released volume Date of failure Country Environmental consequences Reservoir volume Dam type Notes
Padcal No. 2 80,000[33]
32,000[34] 		1992
2 January 		Philippines Damaged "large tracts of prime agricultural land"; mine paid penalties to provincial treasury of Pangasinan.[35] 80,000[36]   Copper mine. Dam wall collapsed.
Mariana dam disaster
(Bento Rodrigues, Samarco)[37] 		60,000
32,000 		2015
5 November		BrazilSignificant contamination of Rio Doce and Atlantic Ocean.55,000 Iron ore tailings[38] Flávio Fonseca de Carmo, Luciana Hiromi et al. say 43x106 m3 of tailings released, which was 80% of the stored volume.
Brumadinho dam disaster12,0002019 January 25BrazilMetals in tailings to be incorporated into rivers' soil.EarthIron ore tailings.
1000 2010 October 4 Hungary The waste extinguished all life in the Marcal river, alkaline mud reached the Danube     Red mud
Sipalay 30,000[39] [40] 1982
8 Nov.[41] 		Philippines "Widespread inundation of agricultural land up to 1.5 m high" 37,000[42]   Dam failure, due to slippage of foundation
15,000[43]
23,600 		2014
4 August 		Canada   74,000[44]   4.5 Mm3 water, 10 Mm3 metals-laden tailings, plus interstitial water in tailings.
American Cyanamid 11,400[45] 1962 U.S.A. Acidic water flowed into a wetland called Hooker's Prairie. It was contained there and limed before discharge into South Prong of Alafia River. Phosphate, Florida.
5,000–10,000 2012
3 August 		Philippines Balog and Agno Rivers heavily polluted. 250,000[46]
102,000 		  Copper mine
6,000–8,000 2004
30 Nov 		Canada Tlatzen First Nation alleges mercury has destroyed fishery in the lake.     Mercury mine waste containment dam collapses.[47]
6,800 1994
2 Oct 		U.S.A.       Water from a clay settling pond. Majority of release contained on adjacent mining area; 500,000 m3 escaped into a creek[48]
4,500
6,800 		1998
25 April		Spain   15,000   Acidic tailings containing heavy metals
4,200 1995
19 August 		Guyana   5,250   Gold mine. Tailings release contained cyanide.
4,100 2008
22 Dec 		U.S.A. Heavy metals; large fish kill; town inundated;     Fly ash slurry from a coal-fired power plant.
3,500 1981
20 January 		Soviet Union   27,000   Iron.
1,500–3,000[49] 1937
27 May 		Mexico > 300 human fatalities 25,000 (estimate)[50]   Silver and gold mine.
Quinette, Maemot 2,500 1985 Canada River valley filled with waste for 2.5 km.     Coal mine.
Rio Pomba Cataguases 2,000 2007
10 January 		Brazil       Bauxite (Aluminum) mine
2,000 1980
13 Oct 		U.S.A. Tailings flow 8 km downstream and inundate farmland.     Copper mine.
1,900 1994
19 Nov 		U.S.A. Spill into wetlands and Alafia River     Water from a clay settling pond
690[51] 1994
22 February 		South Africa Slurry travelled 2 km, covering about km2. 17 fatalities. 7,040   Gold mine.[52]
2008 Shanxi mudslide2008China

Further reading

Notes and References

  1. Web site: Tailings Dam Failures: A Review of the Last One Hundred Years. www.infomine.com. December 2010. Azam. Shahad. Li. Qiren. 30 July 2020. dead. https://web.archive.org/web/20131126070721/http://www.infomine.com/library/publications/docs/Azam2010.pdf. 26 November 2013.
  2. David M Chambers, "Long Term Risk of Releasing Potentially Acid Producing Waste Due to Tailings Dam Failure". Center for Science in Public Participation. Page 3 of 12. CSP2.org
  3. Lindsay Newland Bowker and David M Chambers, 2015. csp2.org
  4. Web site: Tailings Dam Failures 1915 – 2014 : CSP2 . www.csp2.org . dead . https://web.archive.org/web/20160304042209/http://www.csp2.org/tailings-dam-failures-1915-2014 . 2016-03-04.
  5. Web site: 3 Ways of Making Mine Tailing Dams more Sustainable. Honrubia. Mario. 3 April 2019. Ennomotive. en-US. 4 April 2019.
  6. Franks, DM, Boger, DV, Côte, CM, Mulligan, DR. 2011. Sustainable Development Principles for the Disposal of Mining and Mineral Processing Wastes. Resources Policy. Vol. 36. No. 2. pp 114–122
  7. News: Schvartsman. Fabio. Announcement about Brumadinho breach dam. Portuguese. 26 January 2019. Vale. 25 January 2019.
  8. News: Firefighters confirm 40 dead, Vale announces list of non-contact employees. 26 January 2019. Isto é. 26 January 2019.
  9. News: Schipani. Andres. Vale mining dam failure leaves 7 dead in Brazil. 26 January 2019. Financial Times. 26 January 2019.
  10. News: Broadle. Anthony. Vale confirms tailings dam break at Feijao mine, echoing 2015 Samarco disaster. 26 January 2019. The Australian Financial Review. 26 January 2019.
  11. Web site: Boechat: Mariana é a maior tragédia ambiental do Brasil. TV UOL. 28 January 2019.
  12. Web site: É a maior tragédia ambiental do Brasil. Mas tem solução. Joao. www.ihu.unisinos.br. 28 January 2019.
  13. News: Brazil dam burst: Six months on, the marks left by sea of sludge. BBC. 5 May 2016.
  14. CBC News, August 2014. cbc.ca
  15. Mineral Policy Institute, August 2014, Chronology of Major Tailings Dam Failures
  16. http://news.bbc.co.uk/2/hi/europe/642880.stm "Death of a river"
  17. Web site: URANIUM: As Cold War abuses linger, Navajo Nation faces new mining push. Manuel. Quinones. 13 December 2011. www.eenews.net. 28 January 2019.
  18. I. Torgoev, A.T. Jakubick, quoted in Book: Merkel. Broder. Schipek. Mandy. The New Uranium Mining Boom: Challenge and lessons learned. 6 October 2011. Springer Science & Business Media. 232. 9783642221224. 3 January 2018.
  19. Web site: Schramm. Manuel. Uranium Mining and the Environment in East and West Germany. Rachel Carson Center Perspectives. 8 January 2018.
  20. News: Watson. Ivan. Kyrgyz Town Lives with Radioactive Soviet Legacy. 30 December 2017. National Public Radio. 5 February 2008.
  21. Web site: Environmental Aspects of Uranium Mining: WNA – World Nuclear Association. www.world-nuclear.org. 28 January 2019.
  22. Book: Collapse. registration. Jared Diamond. 2005. Penguin. 9780143036555., page 452-458
  23. The present situation and prospects for safety online-monitoring system of tailings pond (sic), by ZHOU Hanmin, YUAN Ziqing, SU Jun, YANG Xiaocong and ZHANG Da1, paper presented for the 3rd International Conference on Mechatronics, Robotics and Automation (ICMRA 2015)
  24. Web site: Introduction tailings dam-Alibaba Trade Forums. resources.alibaba.com. 28 January 2019.
  25. Web site: Трагедията в село Згориград (община Враца, България) . 28 July 2012 . dead . https://web.archive.org/web/20120728074246/http://zgorigrad.com/tragediata . 28 July 2012 .
  26. News: Certej 1971, tragedia uitată a 89 de vieţi îngropate sub 300 de mii de metri cubi de nămol. 30 March 2013. Adevărul. 31 August 2013.
  27. Web site: Tailings.info ▪ Mufulira mine tailings breach, Zambia. www.tailings.info. 28 January 2019.
  28. Web site: Nearly 100 dead in Myanmar jade mine collapse. www.aljazeera.com. 28 January 2019.
  29. Web site: Tailings.info ▪ Merriespruit tailings dam failure. www.tailings.info. 28 January 2019.
  30. Web site: Taoshi landslide: hundreds dead, mine owner and government accused. AsiaNews.it. www.asianews.it. 28 January 2019.
  31. Web site: Promotoria de MG denuncia ex-presidente da Vale e mais 15 sob acusação de homicídio doloso em Brumadinho. 21 January 2020.
  32. News: Brumadinho dam collapse in Brazil: Vale mine chief resigns. 3 March 2019.
  33. AGHAM – Advocates of Science and Technology for the People, Center for Environmental Concerns (CEC), and Kalikasan People's Network for the Environment (Kalikasan-PNE) "Environmental Investigation Mission on the Impacts of the Philex Mining Corporation (PMC) Mine Tailings Pond 3 Failure TECHNICAL REPORT",  2013. Page 2 (7/28). Accessed June 2018.
    Harvey Wood, 2012. Disasters and Minewater. IWA Publishing. Page 36. Accessed via EbscoHost e-book publisher.
    Wise Uranium, 2018. "Chronology of Major Tailings Dam Failures"   gives outflow as 80 million tonnes.
  34. Flávio Fonseca de Carmo, Luciana Hiromi, and others, 2017. "Fundão tailings dam failures: the environment tragedy of the largest technological disaster of Brazilian mining in global context"   Perspectives in Ecology and ConservationVolume 15, Issue 3, July–September 2017, Pages 145–151
  35. Catholic Bishops Conference of the Philippines and others, September 2012. "The Philex Mine Tailings Spill Of 2012: An Independent Fact Finding Mission Report", p 18/26. Accessed July 2018.
  36. International Commission on Large Dams (ICOLD), 2001 Tailings Dams Risk of Dangerous Occurrences   P 95. Gives storage and released amounts both as 80 million tonnes. Accessed July 2018.
  37. United Nations, Mine Tailings Storage: Safety Is No Accident "Report Summary"   Accessed June 2018.
  38. United Nations. No date. "Mine Tailings Storage: Safety Is No Accident", pp 6–7. amazonaws.com
  39. Wise Uranium, "Chronology of Major Tailings Dam Failures"   (2018) gives release size as 28 million tonnes. Thus the volume would be 28 million cubic metres if it was all water, and more if the release included tailings solids, which is likely.
  40. Source gives amount as 28 million tonnes. See also the CSP2 table of tailings dam failures,   lines 375-6, which gives a conversion factor of 1.6 (volume/mass).
  41. http://bulatlat.com/main/2011/11/09/mining-related-deaths-destruction-haunt-celebration-of-mine-safety-week/ Bulatlat.com
  42. Center for Science in Public Participation, "Tailings Dam Failures, 1915–2016"   Accessed June 2018.
  43. Jennni Sheppard, "Imperial Metals was warned about height of wastewater in tailings pond most recently in May" CBC News, 5 August 2014
  44. Center for Science in Public Participation, "Tailings Dam Failures, 1915–2016"
    Adam, NASA Earth Observatory, 17 August 2014."Dam Breach at Mount Polley Mine in British Columbia"   Both articles accessed June 2018.
  45. Hi Tech Solutions, 2000. "Evaluation of the Effectiveness of Neutralizing Accidental Spills of Acidic Waste From Holding Ponds"  , p. 5. Accessed June 2018.
  46. Catholic Bishops Conference of the Philippines and others, September 2012. "The Philex Mine Tailings Spill Of 2012: An Independent Fact Finding Mission Report", p 18/26, cites Philippines DENR as estimating the stored tailings mass as 163 million tonnes. Specific gravity of tailings is typically about 1.6 according to Centre for Science in Public Participation, "Tailings Dam Failures, 1915–2016", op. cit. Accessed July 2018.
  47. Mining Watch "We Want to Make Cominco Responsible: Tlatzen Nation"
  48. Mineral Policy Institute Chronology of major tailings dam failures
  49. J L Macias, P Corona-Chavez, and others, 2015. "The 27 May 1937 catastrophic flow failure of gold tailings at Tlalpjahua, Michoacán, Mexico", Natural Hazards and Earth System Sciences 15, pp 1069–1085. Abstract Full pdf   The document is open source. Retrieved June 2018.
  50. The source gives an estimate of 14.7 million tons. Multiplying this by a typical specific gravity for tailings of 1.6, as suggested by the Center for Science in Public Participation, "Tailings Dam Failures, 1915–2016" (op. cit.) gives approximately 25 million cubic metres of volume.
  51. May have been more like 2,000 Mm3. See ICOLD 2001, op cit.
  52. Michael P Davies, "Tailings Impoundment Failures: Are Geotechnical Engineers Listening?" Geotechnical News, September 2002. http://www.pebblescience.org/pdfs/Dam_failuresDavies2002.pdf

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