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Chronology of uranium tailings dam failures

(last updated 6 Oct 2004)

(tailings releases without embankment failure not listed)

Date Location Parent company Type of Incident Release Impacts
(1994) Zirovski vrh, Slovenia Rudnik Zirovski vrh, Gorenja vas ongoing slippage of the slope (7 million t) with the "Borst" tailings deposit (600,000 t) on the top, at velocity of 0.3 m per year - -
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 370,000 m3 of radioactive water, 1,000 tonnes of contaminated sediment Contamination of Rio Puerco sediments up to 110 km downstream
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

Date	Location	Parent company	Type of Incident	Release	Impacts
(1994)	Zirovski vrh, Slovenia	Rudnik Zirovski vrh, Gorenja vas	ongoing slippage of the slope (7 million t) with the "Borst" tailings deposit (600,000 t) on the top, at velocity of 0.3 m per year	-	-
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	370,000 m3 of radioactive water, 1,000 tonnes of contaminated sediment	Contamination of Rio Puerco sediments up to 110 km downstream
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

Sources:

United Nations Environment Programme - Industry and Environment: Environmental and Safety Incidents concerning Tailings Dams at Mines, Results of a Survey for the years 1980-1996, May 1996, 129 p.
United States Committee on Large Dams: Tailings Dam Incidents, Denver, CO, November 1994, 82 p., ISBN 1-884575-03-X
U.S. Nuclear Regulatory Commission: Regulatory Guide 3.11.1, Rev. 1, Operational Inspection and Surveillance of Embankment Retention Systems for Uranium Mill Tailings, October 1980

and others

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