Incidents from 2004 are reported in accordance with the Bachmann Reporting Criteria as outlined in Standard criteria and procedure for recording and reporting incidents.

Date of incident: 18 October 2012

Date reported: 18 October 2012
Quantity: 20 litres

Description of incident: This incident occurred at 1:30 am on the 18 October 2012 in the precipitation and thickening area of the processing plant.

The spill occurred when an air valve was left in an open position feeding precipitation tank number 3. This resulted in material in the tank to foam. The control room operator ceased acidification of the precipitation tank when levels reached 95%. However, due to the release of CO2 and air already inside the tank, a release of foam out of the vent pipe inside and outside of the concrete bund occurred.  Approximately 20 litres of material (covering an area up to 16 m2) ended up outside the bund.

Comments: Soil samples in the impacted area outside the bund were collected for third party analysis.  Results will determine remediation measures which will be undertaken in accordance with Environment Protection Authority (EPA) requirements.

Investigations have determined that the air valve was left in an open position following trial and testing activities during a recent shutdown.  Supplied air is currently not utilised during normal operations.  Site personnel followed relevant Job Safety and Environmental Analysis (JSEA) procedures.  However, the instructions to close and verify that the manual valve was closed were not addressed in the JSEA.

If further trials and tests occur, the Process Manager will ensure that the revised JSEA has been fulfilled.  If supplied air valve is required during routine operations, the air valves will be automated and incorporated into the facilities control systems.  The vents on the precipitation tanks would also be redesigned to prevent a release leaving the concrete bund area.

Date of incident: 10 July 2012
Date reported: 10 July 2012
Quantity: Unknown volume of fumes

Description of incident: At 7:30am fumes were observed emanating from the dry hopper in the Drying and Packaging (D&P) controlled area. The process was shutdown and quarantined until further notice.

Later that day at 17:30 pm fumes and dust were seen to emanate from an open drum that was parked on the filling conveyor. The drum was the last drum filled prior to the earlier incident. All processing operations on site ceased while an investigation proceeds. The D&P area was cleaned.

No personnel were exposed to the fumes in either incident.

Comments: The composition of the fumes is unknown, however is likely to be of UOC origin – dust samples have been taken for analysis. The volume of fumes is also unknown.

An incident investigation has commenced to determine the probable cause of the releases.

The release for both incidents was contained within the controlled D&P area. This area has been quarantined until further notice, and the areas cleared.

The incident did not result in radiological exposure to personnel or any anticipated environmental harm.

Date of incident: 5 January 2012
Date reported: 17 January 2012 (this is an update to the previously reported spill of 6 January 2012)
Quantity: 441 m3

Description of incident: This is an update of the previously reported spill of 6 January 2012.

More details of this spill have been reported to DMITRE. The revised time of the incident is now between 18:54 and 23:44 on 5 January 2012 when the spill was discovered in Wellfield "A" filter skid unit when a part of one of sixteen canister lids failed under pressure causing the lid to strip the remaining threads and fly off. This caused barren leach solution (2mg/L U3O8).

The original estimate was based on a visual basis only, however since then an analysis of the process data trends have been made showing a sudden drop in pump pressure was noted in the control system records which have now been used to update the original spill duration and release volume.

The total spill covered an estimated area of 11,800 m2, the bund was breached with approximately two thirds of the barren solution discharged outside the bunded area. Personal have been excluded from this area, a radiological survey has been undertaken across the area which shows it is below regulatory levels.

The spill occurred as a result of a failure of a canister lid. Currently there is insufficient information to determine the root cause of the lid failure.

Existing monitoring and alarm systems failed to detect the spill due to not having adequate flow instrumentation to cover the flow rate to cover the operation of the wellfield.

Radiation levels appear to be marginally above background readings. The incident is currently being assessed for any environmental harm and site remediation will be undertaken following consultation with DMITRE and EPA.

There has been no injury to personal. Uranium One are currently undertaking a full investigation report.

Date of incident: 6 January 2012
Date reported: 6 January 2012
Quantity: 30 m3

Description of incident: The incident occurred at approximately 05:15 am within the Wellfield “A” area.

A filter canister lid failed in the wellhouse causing a spill of approximately 30 cubic metres of injection mining acidified barren leach solution (2mg/L U3O8) of about pH 2.5.

The night shift supervisor on his rounds noticed a spray of liquid from one of the wellfield filter skid canisters.

The solution has been contained within the wellfield, however approximately 10 m3 overtopped the bunded area. The solution has soaked into the ground; radiation measurements indicate 1-4 cps (counts per minute), just above background.

Personal are excluded from this area until it dries and is cleaned up.

The canister lid may have been over tightened thus inducing cracks to the lid. All other filter canister lids are being checked for any visual cracks.

Radiation levels appear to be in line with background readings. This incident did not result in any environmental harm or injury to personal.

Date of incident: 25 October 2011
Date reported: 25 October 2011
Quantity: 4 m3 uranium oxide concentrate slurry (approximately 30% solids)

Description of incident:
Product in the yellowcake storage tank (a tank located in the drying and packing plant which contains slurry from the uranium thickener) was accidentally released while diluting contents of the tank with water, and then transferring material from the uranium thickener. The valve at the bottom of the tank had been left open from the previous day's attempts to flush solids in the tank and reduce the strain on the tank agitator.

The spill was fully contained by a concrete containment bund, fitted with concrete sumps and automatic sump pumps that enable a direct transfer back to the uranium thickener.

Probable cause of the incident has been attributed to operator error - the valve on the yellowcake storage tank was not checked by maintenance staff prior to adding water and transferring uranium oxide.

Remedial actions included the cessation of all work in the drying and packing plant. The uranium thickener underflow pump which feeds the yellowcake storage tank was isolated. Cleanup of the residues in the bund sump was then undertaken.

The incident did not cause any environmental harm or injury to personnel, an investigation into the incident is underway.

For more information

For inquiries relating to the mining operation please contact the Mining Regulation Branch
Phone: + 61 8 8463 3484