The

structural failure Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load (weight, force, etc.) without breaking and includes the study of past structural failures in order to ...

tailings dam A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Tailings can be liquid, solid, or a slurry of fine particles, and are usually highly toxic and poten ...

s 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. 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.

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. 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.

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.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 Tailings dam failures involving significant ecological damage include: * the Sino-Metals Leach Zambia dam disaster, Zambia in February 2025, when a tailings dam constructed for copper extraction by Sino-Metals Leach Zambia catastrophically failed, dumping approximately 50 million liters of acidic and highly toxic

waste Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor Value (economics), economic value. A wast ...

into the

Kafue River The long Kafue River is the longest river lying wholly within Zambia. Its water is used for irrigation and for generating Hydroelectricity, hydroelectric power. It is the largest tributary of the Zambezi, and of Zambia's principal rivers, it ...

ecosystem, killing riverine ecosystems and impacting the water and irrigation supply of 60% of Zambia's population. * the Jagersfontein Tailings Dam Collapse, South Africa in September 2022, was a structural failure of a tailings dam used by a stockpile mineral reprocessor, resulting in a mudslide through the town and surrounding farmland. * the Brumadinho dam disaster, Brazil, 25 January 2019, where as many as 252 people are unaccounted for, and at least 134 are dead. The disaster released 12 million cubic meters of iron waste leading to the Paraopeba River. * the Bento Rodrigues dam disaster, Brazil, 5 November 2015, considered the worst environmental disaster in Brazil's history, killed 19 people when an iron ore containment dam failed and released 60 million cubic meters of iron waste. * the Mount Polley mine, British Columbia, 4 August 2014, which released 10 million cubic metres of water and 4.5 million cubic metres of metals-laden tailings from a holding reservoir. * the

Ok Tedi environmental disaster The Ok Tedi environmental disaster caused severe harm to the environment along of the Ok Tedi River and the Fly River in the Western Province of Papua New Guinea from 1984 to 2013, with the damage still ongoing. The lives of 50,000 people have ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, which destroyed the fishery of the

Ok Tedi River The Ok Tedi is a river in New Guinea. The Ok Tedi Mine is located near the headwaters of the river, which is sourced in the Star Mountains. It is the second largest tributary of the Fly River. Nearly the entirety of the Ok Tedi runs through the N ...

, continuously from 1984 through 2013 * the Sotkamo metals mine, Finland, 4 November 2012, released "hundreds of thousands of cubic metres" of waste water which raised concentrations of uranium, nickel, and zinc in nearby Snow River, each to at least 10 times the harmful level. * the Ajka alumina plant accident, Hungary, 4 October 2010, which released one million cubic metres of red mud, a waste product of aluminum refining, flooding the village of Kolontár and killing the Marcal River. * the Baia Mare cyanide spill, Romania, 30 January 2000, called the worst environmental disaster in Europe since the

Chernobyl disaster On 26 April 1986, the no. 4 reactor of the Chernobyl Nuclear Power Plant, located near Pripyat, Ukrainian Soviet Socialist Republic, Ukrainian SSR, Soviet Union (now Ukraine), exploded. With dozens of direct casualties, it is one of only ...

"Death of a river"
''BBC'', 15 February 2000 * The Doñana disaster, southern Spain, 25 April 1998, which released 4 million-5 million cubic metres of acidic tailings containing heavy metals. * the Merriespruit tailings dam disaster, South Africa occurred on the night of 22 February 1994 when a tailings dam failed and flooded the suburb of Merriespruit, Virginia. Seventeen people were killed as a result. * the

Church Rock uranium mill spill The Church Rock uranium mill spill occurred in the U.S. state of New Mexico on July 16, 1979, when United Nuclear Corporation's tailings disposal pond at its Uranium mining#Heap leaching, uranium mill in Church Rock, New Mexico, Church Rock breac ...

in New Mexico, 16 July 1979, the largest release of radioactive waste in U.S. history * three uranium tailings dams near the town of Ak-Tüz, present-day

Kyrgyzstan Kyrgyzstan, officially the Kyrgyz Republic, is a landlocked country in Central Asia lying in the Tian Shan and Pamir Mountains, Pamir mountain ranges. Bishkek is the Capital city, capital and List of cities in Kyrgyzstan, largest city. Kyrgyz ...

, collapsed in a December 1964 earthquake, releasing 60% of their radioactive volume () into the Kichi-Kemin River and its agricultural valley * an incident on 7 April 1961, released of uranium mine tailings from operations of the Soviet-era Wismut organization into the Zwickauer Mulde River in the village of Oberrothenbach * the Mailuu-Suu tailings dam failure also in Soviet-era

on 16 April 1958, caused the uncontrolled release of of the radioactive uranium-mine tailings in to spill downstream into a portion of the densely populated

Ferghana Valley The Fergana Valley (also commonly spelled the Ferghana Valley) in Central Asia crosses eastern Uzbekistan, southern Kyrgyzstan and northern Tajikistan. Encompassing three former Soviet republics, the valley is ethnically diverse and relation ...

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 The Olympic Dam mine is a large poly-metallic underground mine located in South Australia, NNW of Adelaide. It is the fourth largest copper deposit and the largest known single deposit of uranium in the world. Copper is the largest contributor ...

, Western Mining Corporation, admitted that their uranium tailings containment had released of up to 5 million m3 of contaminated water into the subsoil. The cost of mine cleanup has typically been 10 times that of

mining industry Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a la ...

estimates when acid drainage was involved., page 452-458

Casualties

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

Largest

The following list focuses on the largest tailings dam failures:

Rate

Environmental damage

Casualties

Largest

References

Further reading