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Olympic Dam mine spill incident summary as reported by BHP Billiton

Date of incident: 17 April 2016
Date reported: 17 April 2016
Quantity: Approximately 210m3

Description of incident:
A spool failure along tailings disposal slurry line 3 pipe (underneath an access roadway structure) resulted in approximately 210m3 of tailings material being spilled within the pipe trace.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public. All contaminated material was contained, cleaned-up and disposed of in accordance with site procedures.

The root cause of the incident was the spool failed from external corrosion due to being in direct contact with the ground.  

To prevent a recurrence, a number of actions have been implemented, including ensuring all build-up of materials against spools are removed during routine inspections and implementing the updated monthly thermography monitoring strategy.


Date of incident: 15 March 2016
Date reported: 15 March 2016
Quantity: Approximately 100m3

Description of incident:
Tailings disposal slurry line 3 pipe failed spilling approximately 100m3 of tailings material. Approximately 75m3 was contained within the pipe trace and approximately 25m3 sprayed outside of the pipe trace onto the adjacent road.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public. All contaminated material was contained, cleaned-up and disposed of in accordance with site procedures.

The root cause of the incident was a failure of the spool through rubber liner damage and external corrosion.  

To prevent a recurrence, a number of actions have been implemented, including updating the maintenance change out strategy for tailings disposal slurry pipe lines and reviewing the thermography monitoring strategy.


Date of incident: 7 September 2015
Date reported: 7 September 2015
Quantity: Approximately 1 gram

Description of incident:
During the internal cleaning of Precipitation Tank 1, approximately 1 gram of ammonium diuranate was ejected from the top of the Precipitation Tank ending up outside of the bunded area onto the adjacent hardstand ground.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public.  All contaminated material was immediately contained, cleaned-up and disposed of in accordance with site procedures.

The root cause of the incident was that the potential for ammonium diuranate to be ejected from the Precipitation Tank during internal cleaning, via an open spool, was not identified.

To prevent a recurrence, a number of actions have been implemented, including reviewing and updating internal procedures to ensure blanks are installed over all open spools during Precipitation Tank cleaning activities.


Date of incident: 5 September 2015
Date reported: 5 September 2015
Quantity: Approximately 5 grams

Description of incident:
During the draining of Precipitation Tank 1 (for route maintenance purposes), a failure of the funnel redirecting discharge material resulted in approximately 5 grams of ammonium diuranate being spilled outside of the bunded area onto the adjacent hardstand ground.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public.  All contaminated material was immediately contained, cleaned-up and disposed of in accordance with site procedures.

The root cause of the incident was the drain line from Precipitation Tank 1 becoming blocked with discharge material, resulting in the overflow of the funnel redirecting discharge material.

To prevent a recurrence, a number of actions have been implemented including the installation of new tank discharge infrastructure and sealing the gap between the cover shed and concrete bund.


Date of incident: 16 March 2015
Date reported: 16 March 2015
Quantity: Approximately 2 grams

Description of incident:
Following a recent settler unit cleaning program, personnel undertaking shut down inspections on the Solvent Extraction (SX) settler units noticed approximately 2 grams of ammonium diuranate on the hardstand ground adjacent to the bunded area.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public.  All contaminated material was immediately contained, cleaned-up and disposed of in accordance with site procedures.

The root cause of the incident related to the planning and handling practices used during the plant shutdown, which was inadequate to appropriately manage hazards.
To prevent a recurrence, the company has reviewed and updated work instructions for SX settler cleaning procedures and improved spill protection controls for future cleaning programs.

To prevent a recurrence, a number of actions have been implemented including the installation of new tank discharge infrastructure and sealing the gap between the cover shed and concrete bund.


Date of incident: 31 October 2014
Date reported: 31 October 2014
Quantity: Approximately 5 grams

Description of incident:
Solvent Extraction (SX) personnel segregating waste in bins dislodged approximately 5 grams of ammonium diuranate from a hose onto the hardstand ground adjacent to the waste bins.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public. All contaminated material was immediately contained, cleaned-up and disposed of in accordance with site procedures. A contributing factor to the incident was personnel not following correct waste cleaning/wrapping procedures prior to disposal into bins.

To prevent a recurrence the company has clarified internal procedures for waste cleaning/wrapping, updated relevant training programs, retrained relevant personnel and installed signs in the SX plant outlining requirements for waste management.


Date of incident: 24 January 2014
Date reported: 24 January 2014
Quantity: Approximatley 1-2 grams

Description of incident:A company officer noticed uranium Solvent Extraction (SX) waste was placed in the incorrect bin in the Processing Waste Transfer Station. On transferring this material several grams of ammonium diuranate spilled onto the hardstand ground adjacent to the waste bins.

The company's investigation identified that waste disposal from the uranium SX was non-compliant with the site's Waste Management Plan.

Comments: The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public. A contributing factor to the incident was a gap in awareness of the procedures for waste disposal from the uranium SX area.

To prevent a recurrence the company has revised procedures for disposal of uranium SX waste, updated relevant training programs for SX and waste contractors, and further reviewed waste management operations within the processing area.


Date of incident: 9 July 2013
Date reported: 9 July 2013
Quantity: Approximatley 15 grams

Description of incident:A company technician during a routine inspection noticed approximately 15 grams of ammonium diuranate on the ground at two locations within the Solvent Extraction (SX) plant.

The company’s investigation identified that the ammonium diuranate dislodged and fell to the ground from a portable agitator stand that had recently been relocated within the SX plant area.

Comments:
The company reported no environmental impacts and no health, safety or radiological impacts to employees or members of the public. The root cause of the incident was determined to be restricted access to the agitator stand due to a “fall from height” risk preventing appropriate cleaning and inspection of the stand.

To prevent a recurrence, the company has revised daily work area inspections and designed new portable agitator stands that are self bunded and incorporate safe access to the top levels for cleaning and inspection.


Date of incident: 3 August 2012
Date reported: 4 August 2012
Quantity: 130 m3

Description of incident:Approximately 130 m3 of pregnant liquor solution (PLS), overflowed from the PLS pond as a result of a failed level sensor. The majority of the spill was contained in a purpose built stormwater system around the southern perimeter of the PLS pond.

Comments:
The company reported no serious or material environmental harm (the spill was contained in a disturbed area containing no vegetation), no abnormal radiation exposure to the workforce, no ingestion or inhalation exposure, no injuries and no impact to members of the public. The PLS and contaminated soil was collected and disposed of in accordance with site procedures.

An investigation into the root cause of the spill has been completed, which has resulted in a number of actions to minimise the risk of recurrence. A follow up site inspection was conducted by DMITRE and EPA representatives on 30 August 2012, which confirmed that the spill was cleaned up appropriately.


Date of incident: 14 March 2013
Date reported: 15 March 2013
Quantity: 150 m3

Description of incident:
Approximately 150 m3 of tailings slurry leaked from slurry line 3 as a result of failure of one of the flexible joints in the slurry line. The majority of the tailings slurry was contained within the bunded pipe trace. A small volume of slurry sprayed onto the tailings storage facility and evaporation pond embankment walls

Comments:
BHP reported no serious or material environmental harm, no abnormal radiation exposure to the workforce, and no impact to members of the public as a result of this spill. The specific tailings disposal pumps were shut down and not restarted until the faulty joint was repaired and the root cause of the spill was investigated. The slurry spill and contaminated soil was collected and disposed of in accordance with site procedures. A follow up site inspection was conducted by DMITRE and EPA representatives on 17 May 2011 which confirmed that the spill was cleaned up appropriately.


Date of incident: 31 October 2011
Date reported: 31 October 2011
Quantity: 3 m3

Description of incident:
Approximately 3 m3 of diluted barren strip solution overflowed from a sump within the precipitation area resulting in a small amount of concentrated uranium residue being deposited outside of a bunded area (but within a tertiary containment area).

Comments: The company reported no environmental impacts, no abnormal radiation exposure to the workforce, no ingestion or inhalation exposure, no injuries and no impact to members of the public as a result of this incident. All contaminated material was immediately contained, cleaned-up and disposed of in accordance with site procedures.

An investigation into the root cause of the spill has been completed, which has resulted in a number of actions to minimise the risk of recurrence. These actions have since been implemented and confirmed with DMITRE and EPA.


Date of incident: 2 August 2011
Date reported: 3 August 2011
Quantity: 500 grams

Description of incident:
Ammonium diuranate (ADU) was emitted from the Precipitation Plant (Calciner A Stack) which resulted in aproximately 500 g of solid ADU product being released outside the bund area. The product was confined to a small area south of the Calciner building and within the tertiary containment area.

Comments:
BHP reported no environmental impacts or radiation exposure to the workforce or members of the public as a result of this incident. Contaminated material was removed and disposed of in accordance with site procedures and a surface contamination survey of the out of bund areas was performed following clean up. Calciner A was shut down and was not restarted until the cause of the spill was identified.


Date of incident: 1 May 2011
Date reported: 3 May 2011
Quantity: 180 m3

Description of incident:
Approximately 180 m3 of acidic tailings slurry was released from slurry line 2 at Tailings Disposals as a result of the premature failure of a rubber sleeve on a pinch valve. The majority of the slurry was released outside the bunded area (but within a previously disturbed spill capture area), to the southwest of Solvent Extraction.

Comments:The company reported no serious or material environmental harm, no abnormal radiation exposure to the workforce, no ingestion or inhalation exposure, no injuries and no impact to members of the public as a result of this spill. The slurry spill was collected and disposed of in accordance with site procedures. An investigation of the incident resulted in a number of actions which have since been implemented to minimise the risk of recurrence.


Date of incident: 15 February 2011
Date reported: 15 February 2011
Quantity: 120 m3

Description of incident:Failure of a butt weld joint in the high-density polyethylene (HDPE) evaporation pond return liquor pipeline (EPRL) west of the Solvent Extraction Area resulting in leakage of acidic liquor. The spill was fully contained within the Tailings Retention System (TRS) pipeline corridor. The pipeline was shut down and arrangements made to clean up the spill and repair the pipe joint.

Comments:
There was no radiation exposure to the workforce and no impact on members of the public. There was no serious or material environmental harm caused or threatened and no impact to native vegetation.


Date of incident: 14 February 2011
Date reported: 14 February 2011
Quantity: 150 grams

Description of incident:
Ammonium diuranate was dislodged during maintenanace activities of structural shell and cladding in the Precipitation Area of the processing plant. Small amounts were noted on the footpath and roadway outside the bunded area.

Comments: All of the visible material was cleaned-up. Procedures have been amended to ensure no further potential for similar incidents to occur. Radiation monitoring by BHP Billiton indicated no risk to human health or the environment.


Date of incident: 23 September 2010
Date reported: 23 September 2010
Quantity: to be determined

Description of incident:In evaporation pond 3 B a tear was found at the weld between the HDPE 'boot' that joins the liquour return outlet pipe from the tailings storage facility to the HDPE liner of the evaporation pond. Liquor is believed to have accumulated betweent he HDPE geomembrane liner ane the underlying compacted low permeability clay liner. Liquor that accumulated under the HDPE liner was observed to be re-entering the evaporation pond through a second tear located 1m above the first tear.

Comments:
There was no radiation exposure to the workforce during the spill and no impact to members of the public. No serious or material environmental harm caused or threatened. Liquor which has collected between the HDPE liner and the compacted clay liner will be pumped out and the liner repaired.


Date of incident: 1 September 2010
Date reported: 1 September 2010
Quantity: 86 m3

Description of incident:Failure of the butt weld joint in the HDPE evaporation pond return liquor pipeline (EPRL) along the East side of TSF cell 2/3 ramp resulting in leakage of acidic liquor. The spill was fully contained within the TRS pipeline corridor. No liquor discharged out of the bunded area. The pipeline was shut-down and arrangements made to clean-up the spill and repair the pipe joint.

Comments:There was no radiation exposure to the workforce and no impact on members of the public. There was no serious or material environmental harm caused or threatened and no impact to native vegetation.


Date of incident: 30 September 2009
Date reported: 30 September 2009
Quantity: <0.1 m3

Description of incident:A small leak developed in tailings line 1 adjacent to the northeast corner of Evaporation Pond 2 resulting in tailings slurry spray outside the pipeline corridor onto a nearby undisturbed dune. Less than 0.1m3 of slurry was discharged outside the bunded area. The tailings pipeline was shutdown and arrangements made to clean-up the spill.

Comments:
No personnel had any ingestion or inhalation exposure to the material and there were no injuries associated with the spill. There was no radiation exposure to the workforce during the spill. There was no radiation impact on members of the public. There was no serious or material environmental harm caused or threatened.


Date of incident: 3 February 2009
Date reported: 3 February 2009
Quantity: 250 m3

Description of incident:
A spill of approximately 250 m3 of tailings occurred when a tailings line failed causing tailings slurry to spray onto southern wall of Tailings Cell 4. The spilt tailings were contained within the bunded tailings pipeline corridor and associated drainage area.

Comments:
No personnel had any ingestion or inhalation exposure to the material and there were no injuries associated with the spill. No radiation exposure to the workforce during the spill. No radiation impact on members of the public. No serious or material environmental harm caused or threatened as the spill was wholly contained.


Date of incident: 7 January 2009
Date reported: 7 January 2009
Quantity: 300 grams

Description of incident:Whilst relocating pipework, a small amount of solid ammonium diurinate was spilt outside the bunded area resulting in a small amount of solids being deposited over several metres.

Comments:
No personnel were exposed to the material and there were no injuries associated with the spill. No radiation exposure to the workforce. No radiation impact on members of the public. No serious or material enviornmental harm caused or threatened as the spill was wholly contained.


Date of incident: 10 December 2008
Date reported: 10 December 2008
Quantity: 50 m3

Description of incident:
Approximately 80 m3 of tailings leach tank feed discharged into a bunded area causing 50m3 of material to overflow into the processing plant area.

Comments:
Cleanup consisted of returning the material inside the bund to the process and material outside the bund to the tailings system. There was no material harm to either the environment or the employees.


Date of incident: 8 October 2008
Date reported: 8 October 2008
Quantity:1-2 m3

Description of incident:Liquor containing ammonium diuranate (ADU) escaped from a pressurised precipitation tank. Released ADU was contained within the bunded area except for approximately 20 litres of liquor containing ADU which went outside the bund onto a compacted gravel area. All material was contained within the immediate area.

Comments:
The spilt material was cleaned up and either returned to the process or disposed of within the tailing storage facility. The incident did not cause any environmental harm or injury to personnel.


Date of incident: 25 August 2008
Date reported: 25 August 2008
Quantity:<1 m3

Description of incident:Ammonium diuranate (ADU) was detected in sub-potable water when ADU was noticed as a yellow coating on the dried surfaces of washed shipping containers. The ADU entered the sub-potable system following the connection of a hose to a pump within the precipitation area.

Comments:
The discharge was fully within the plant area and the operation’s tertiary containment system. The incident did not cause any environmental harm or injury to personnel. As the sub-potable water system is isolated from the potable water system, there was no radiological dose to any worker, member of the public or the environment.


Date of incident: 20 March 2008
Date reported: 20 March 2008
Quantity: 70 m3

Description of incident:Approximately 70 m3 of tailings escaped into the tailings pipeline corridor from a pipe failure. The process was shutdown and repairs carried out. No material escaped beyond the bunded area and there is no impact on the general environment or any personnel.

Comments:
All the material is being recovered and will be disposed of in the tailings retention system. No personnel had direct contact with the tailings and the incident did not cause any environmental harm or injury to personnel.


Date of incident: 18 February 2008
Date reported: 18 February 2008
Quantity: 270 m3

Description of incident:Approximately 270 m3 of tailings escaped into the tailings pipeline corridor from a pipe failure. The process was shutdown and repairs carried out. No material escaped beyond the bunded area and there is no impact on the general environment or any personnel.

Comments:
All the material was recovered and disposed of in the tailings retention system. No personnel had direct contact with the tailings and the incident did not cause any environmental harm or injury to personnel.


Date of incident: 1 January 2008
Date reported: 1 January 2008
Quantity: 30 m3

Description of incident:A flexible section of pipe failed causing some 30 m3 of tailings material to be discharged beyond the secondary containment area but remained within the tertiary containment. The fluid was essentially barren and no material entered the general environment. The pipe has now been replaced.

Comments:All available excess liquor was recovered. No personnel had direct contact with the liquor and the incident did not cause any environmental harm or injury to personnel.


Date of incident: 10 October 2007
Date reported: 11 October 2007
Quantity: 50 m3

Description of incident:Approximately 50 m3 of liquor from the solvent extraction area overflowed the HDPE lined scuttle pond into an adjoining unlined overflow pond. This pond was designed for temporary storage in the event of an unplanned incident.

Comments:
All excess liquor was recovered from the pond. No personnel had direct contact with the liquor and the incident did not cause any environmental harm or injury to personnel.


Date of incident: 29 September 2007
Date reported: 29 September 2007
Quantity: 70 m3

Description of incident:Approximately 70 m3 tailings leach overflowed a bund containing the Tails Leach Tank No. 4. The tank was being drained at the time. No material left the engineered controls of the plant perimeter.

Comments:
Work commenced immediately to recover the spilt liquor. No personnel had direct contact with the liquor and the incident did not cause any environmental harm or injury to personnel.


Date of incident: 9 February 2007
Date reported: 12 February 2007
Quantity: Approximatley 1 litre

Description of incident:A small quantity of uranium oxide was released into an unbunded area south of the Calciner building.  This occurred when a valve was left open on a diesel tank, which resulted in diesel overflowing the diesel tank bund and flowing towards the packing shed sump.  The spilled diesel caused the packing shed sump to overflow, mobilising the small quantity of uranium oxide beyond the bunded area. The volume of diesel which overflowed the bund was 1000 litres.

Comments:
All of the uranium concentrate was recovered and disposed of in the Tailings Storage Facility. It has been assessed that there was no significant environmental impact, nor was there any occupational health or safety impact.


Date of incident: 20 April 2005
Date reported: 20 April 2005
Quantity: 12 m3

Description of incident:28m3 of tailings slurry was released into an earthen bund containing valve station #4. A tailings line was recommissioned following a planned shutdown for maintenance on the tailings line. Approximately 12 m3 overflowed the bund into a previously disturbed area consisting largely of saltbush that had revegetated naturally.

Comments:
All of the tailings slurry was recovered and returned to the Tailings Storage Facility. It has been assessed that there was no significant environmental impact and no occupational health or safety impact. WMC will review standard operating procedures to prevent a reoccurrence.


Date of incident: 5 January 2005
Date reported: 6 January 2005
Quantity: 117 m3

Description of incident:Slurry feed escaped from a rubber-lined steel elbow on the feed line located at the SE corner of Cell 2 within the Tailing Retention System. The spill resulted from the failure of the rubber lining and subsequent corrosion of the steel pipe.

Comments:
All of the slurry feed was contained in a bunded area. All residual slurry was returned to the Tailing Storage Facility (TSF). There was no environmental harm or injury to personnel and no material escaped beyond the containment bund.


Date of incident: 8 September 2004
Date reported: 10 September 2004
Quantity: 250 m3

Description of incident:
Evaporation liquor back flowed through an isolation valve, a non-return valve and through a pump located at Evaporation Pond 1 (EP1). The pump had been drained for maintenance. This work was completed on 8/9. The back flow occurred when evaporation liquor was being pumped from EP 3 to EP 2. The leakage was detected on 10 September 2004 during a regular inspection of the area.

Comments:
The spill was contained within the containment bund surrounding the EP1 pump station. The liquor was cleaned up and returned to the Evaporation Pond. No environmental harm or injury to personnel. WMC will improve their daily inspection and monitoring procedures to ensure prompt detection of leaks. Pump start-up procedures will also be improved.


Date of incident: 21 May 2004
Date reported: 21 May 2004
Quantity: 460 m3

Description of incident:
A spill of pregnant liquor solution (PLS) containing 0.014% uranium occurred when a weld failed in a high density polythene pipe. The pipe was located in the Hydrometallurgical Process Plant area.

Comments:The spill was contained within the process plant area. The material was cleaned up and returned to either the process circuit or tailings storage facility. No environmental harm or injury to personnel.


Date of incident: 8 February 2004
Date reported: 8 February 2004
Quantity: 25 m3

Description of incident:Tailings leaked under pressure as a result of a small tear in a tailings delivery line located near SE corner of tailings retention system No. 1. 2 m3 sprayed beyond the bund surrounding the tailings pipeline corridor.

Comments:
No injury to personnel and minimal environmental impact. A small area of vegetation was affected by the sprayed tailings. The affected area will be cleaned up as per standard procedure.


Date of incident: 15 December 2003
Date reported: 15 December 2003
Quantity:145 m3

Description of incident:Raffinate containing 0.0043% uranium discharged to the ground in the process plant area due to failure of a fibreglass pipe in the hydrometallurgical area.

Comments:
The spill was contained within the process plant area. The material was cleaned up and returned to either the process circuit or tailings storage facility. No environmental harm or injury to personnel.


Date of incident: 19 October 2003
Date reported: 19 October 2003
Quantity:130 m3

Description of incident:Liquor containing 0.26% copper and 0.022% uranium overlapped the eastern wall of Evaporation Pond 4B as a result of wave action caused by strong winds.

Comments:
The escaped liquor was contained by an external bund. The material was cleaned up using vacuum trucks and returned to the tailings storage. No liquor escaped into the undisturbed environment.
Whilst the levels in the pond were within the specified freeboard limits, these limits will be reviewed. No environmental harm or injury to personnel.


Date of incident: 15 October 2003
Date reported: 15 October 2003
Quantity: 110 m3

Description of incident:Pregnant liquor solution (PLS) containing 0.029% uranium overflowed the bund surrounding #1 Clarifier system, following overflow of clarifier tanks.

Comments:
The spill was contained well within the process plant area and was contained within tertiary containment. The material was cleaned up and returned to the process circuit or tailings storage facility. Gamma dose measurements taken before clean up operations were completed recorded rates at background levels, i.e. no occupational or environmental hazard. No environmental harm or injury to personnel.


Date of incident: 20 August 2003
Date reported: 20 August 2003
Quantity: 63 m3

Description of incident:Tailings solids and liquor containing approx 0.03% uranium flowed into the bunded tailings pipeline corridor adjacent to Cell 1 of Tailings storage facility. Caused by failure to seal an isolation valve subsequent to routine maintenance.

Comments:
The spill was totally contained within existing bunds. No environmental harm or injury to personnel.


Date of incident: 18 February 2003
Date reported: 19 February 2003
Quantity: 210 m3

Description of incident:Spill of acidic raffinate liquor containing 172ppm uranium due to a pipe failure in the hydrometallurgical area.

Comments:
The spill was contained well within the process plant area within tertiary containment. The material has been cleaned up and returned to the process circuit. Gamma dose rate measurements taken before and after the clean up confirm no occupational or environmental hazard.