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Chronology of uranium tailings dam failures

(last updated 7 Oct 2021)

(tailings releases without embankment failure not listed)

Date Location Parent company Type of Incident Release Impacts
2012, Nov. 4 Sotkamo, Kainuu province, Finland (nickel mine, with uranium by-product production planned) Talvivaara Mining Company Plc leak from gypsum pond through a "funnel-shaped hole" hundreds of thousands of cubic metres of contaminated waste water nickel and zinc concentrations in nearby Snow River exceeded the values that are harmful to organisms tenfold or even a hundredfold, uranium concentrations more than tenfold (view details)
(1994) Žirovski vrh, Slovenia Rudnik Žirovski vrh , Gorenja vas ongoing slippage of the slope (7 million t) with the "Boršt" tailings deposit (600,000 t) on the top, at velocity of 0.3 m per year, in 2014 still at 3 cm per year, and in 2020 at 2 cm per year (view details). - -
1994, Feb. 14 Olympic Dam, Roxby Downs, South Australia WMC Ltd. leakage of tailings dam during 2 years or more release of up to 5 million m3 of contaminated water into subsoil ?
1985 Lengenfeld, Vogtland, Germany Wismut localized dam failure ? minor
1984, Jan. 5 Key Lake, Saskatchewan, Canada Cameco (67%), Uranerz (33%) overtopping of process water reservoir, due to poor management 87,330 m3 of contaminated water ?
1979, Jul. 16 Church Rock, New Mexico, USA United Nuclear dam wall breach, due to differential foundation settlement and direct exposure of the dam to tailings solution 370,000 m3 of radioactive water, 1,000 tonnes of contaminated sediment Contamination of Rio Puerco sediments up to 110 km downstream
> Download: Abnormal occurence; Mill Tailings Impoundment Failure, U.S. NRC, Federal Register Vol. 45, No. 8, January 11, 1980, p. 2424-2425 (1.4M PDF - ADAMS Acc. No. ML101040064)
1979, Mar. 1 Union Carbide, Uravan, Colorado, USA Union Carbide two slope slides, due to snow smelt and internal seepage - -
1977, Apr. Western Nuclear, Jeffrey City, Wyoming, USA Western Nuclear Tailings slurry overtopped the embankment because of insufficient freeboard space, considerably less slope than the requisite 3 horizontal to 1 vertical, and a loss in structural integrity caused by the melting of snow interpersed with the fill used to construct the embankment. 40 m3 of tailings and 8,700 m3 of liquid "no offsite contamination"
1977, Feb. 1 Homestake, Milan, New Mexico, USA Homestake Mining Company dam failure, due to rupture of plugged (frozen) slurry pipeline 30,000 m3 of tailings and 7,600 - 30,000 m3 of liquid no impacts outside the mine site
1976, Apr. 1 Kerr-McGee, Churchrock, New Mexico, USA Kerr-McGee dam failure, due to differential settlement of foundation soils "minor quantity" ?
1971, Mar. 23 Western Nuclear, Jeffrey City, Wyoming, USA Western Nuclear dam failure, due to break in tailings discharge line ? "no offsite contamination occured"
1971, Feb. 16, Petrotomics, Shirley Basin, Wyoming, USA Petrotomics secondary tailing dike failure 7.6 m3 of liquid liquid lost to unrestricted area
1967, Jul. 2 Climax, Grand Junction, Colorado, USA ? tailing dike failure of unapproved retention system 1,200 - 12,000 m3 of waste liquid effluent release into Colorado river
1967, Feb. 6 Atlas Corp., Moab, Utah, USA   auxiliary decant failure, overflow from main tailings pond overflowed aux. decant system 1700 m3  
1963, Jun. 16 Utah Construction, Riverton, Wyoming, USA ? The dam was intentionally breached and a 2-ft depth of effluent was released to prevent uncontrolled release of the impoundment contents during heavy rain ? ?
1962, Jun. 11 Mines Development, Edgemont, South Dakota, USA ? dam failure, due to unreported causes 100 m3 tailings released reached a creek and some were carried 25 miles to a reservoir downstream
1961, Dec. 6 Union Carbide, Maybell, Colorado, USA Union Carbide dam failure from unreported causes 280 m3 effluent released did not reach any stream
1960 Gunnar mine, Beaverlodge area, Saskatchewan, Canada Gunnar Mines Ltd. dam failure ? tailings release into Lake Athabasca, creating Langley Bay tailings delta
1959, Aug. 19 Union Carbide, Green River, Utah, USA Union Carbide dam failure during flash flood 8,400 m3 tailings and effluent reach a creek and river
1958, Apr. Mayluu-Suu tailing #7, Kyrgyzstan   dam failure after earthquake and heavy rain 600,000 m3 a lot of houses in the town destroyed, people were killed, and the tailings were spread over 40 km down by the river, contaminating flood plains
> View photo (UNEP/GRID-Arendal)
1954 Lengenfeld, Vogtland, Germany Wismut dam failure during flooding event 50,000 m3 tailings spread 4 km down by the river, create wetland by damming up


and others

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