Environment & Safety

Smoke underground

Once the area was declared safe, electricians confirmed the source of the smoke as a 600V cable that appears to have shorted to ground. Federal and provincial regulators were notified. An investigation to determine the cause of the short is ongoing.

Reportable Discharge

The pond was taken offline and drained. It will remain offline until an inspection and repairs can be completed. The cause is being investigated. Provincial and federal regulators were notified.

Smoke underground

During an attempt to reset power to the underground, two employees reported smoke on the 640 level of the mine. The area was evacuated and the emergency response team (ERT) responded in accordance with emergency procedures. The ERT investigated, confirmed that there was no active fire and identified the source of the smoke as being two damaged electrical cables that feed the 640 level substation. 

Electricians isolated damaged electrical lines and restored power to the underground. Federal and provincial regulators were notified.  An investigation to determine the cause of the damaged cables is ongoing.

Release of treated water

Approximately 800 cubic metres of treated water was released from a possible liner tear in pond 3 from January 29 to February 2, 2019. Lab analysis shows the treated water was of good quality and met regulatory limits for release.

The pond was taken offline and drained. It will remain offline until an inspection and repairs can be completed. It is expected that surface ice and changing water levels caused the tear. Provincial and federal regulators were notified.

Reportable release

A liquid propane leak at the propane vapourizer building was observed by employees, and following monitoring by the safety officer, the plumber initiated work to repair the valve. The supply line was isolated and underground work was not started while the heating was inoperable.

It is expected that the incident was caused by a rapid change in extreme temperatures. Repairs were completed by the site plumber. Provincial and federal regulators have been notified.

Equipment recertification

On November 20th, an employee identified that required paperwork for extending the use of hoist ropes had not been submitted to the Ministry of Labour Relations and Workplace Safety. The necessary inspections had been completed but were not submitted on time for recertification.

The applicable equipment has been taken out of service until approval from the Ministry is received. The oversight is under investigation. Provincial and federal regulators were notified.

Release of treated water

Inspection of recent liner repairs in the storage ponds that are part of the water treatment system at the McArthur River operation led to the discovery of water leakage. Approximately 1,200 cubic metres of treated water was released from this pond.

The storage pond was taken out of service, drained and repairs initiated. Provincial and federal regulators were notified.

Ammonia release

A refrigeration mechanic entered the Module 1 freeze plant at about 2:15 p.m. and noticed the smell of ammonia. The mechanic identified that a small amount of ammonia had leaked from a cracked sight glass on a vessel. None of the ammonia detectors in the plant were in alarm.

The vessel has been taken out of service pending repair, and the cause is being investigated. Provincial and federal regulators were notified.

Release of treated water

Inspection of the storage ponds that are part of the water treatment system at the McArthur River operation led to the discovery that approximately 8,000 cubic metres of treated water had been discharged from these ponds.

The storage ponds were taken out of service, drained and repairs initiated. Provincial and federal regulators were notified.

Reportable Release

A fitting failure on the hot water heating system caused the release of approximately 600 litres of an ethylene glycol and water mixture into the basement floor of the main camp. The release was contained within the foundation of the building.

The cause of the incident and cleanup options are being investigated. Provincial and federal regulators have been notified.

Sprinkler system alarm

The sprinkler system water pumps in the batch plant began to operate at approximately 1:00 a.m., triggering activation of the emergency response team (ERT).

The ERT responded in accordance with emergency procedures and verified that there was no fire or smoke. The incident is being investigated and provincial and federal regulators have been notified.

Electrical equipment malfunction

At approximately 12:25 a.m., smoke was reported at a surface facility at the McArthur River mine. McArthur River’s emergency response team (ERT) responded, secured the area and ventilated the facility.

Electrical service has been restored. We are investigating the cause of the outage, as well as a similar incident on March 10th. Provincial and federal regulators have been notified.

Transformer malfunction

At approximately 6:20 p.m., smoke was reported at a surface facility at the McArthur River mine. McArthur River’s emergency response team (ERT) responded, secured the area and ventilated the facility. 

Early investigation determined that the smoke resulted from an electrical equipment malfunction.  Electrical service has been restored and the cause of the outage is being investigated. Provincial and federal regulators have been notified.

Action Level Exceedance

The McArthur River operation has identified a discrepancy between test results on samples of treated water from its own lab and results from other labs. Test results from other labs show that an action level for radium in effluent was exceeded during February.

Cameco is investigating to determine the cause of the discrepancy. Until the issue is resolved,  testing for radium in effluent will be done at the Key Lake lab. Test results for all other contaminants in effluent are being reviewed, as are lab procedures at McArthur River. The CNSC and Saskatchewan Ministry of Environment have been notified.

Ammonia release

A refrigeration mechanic entered the main freeze plant at about 3:00 p.m. and noticed the smell of ammonia. The mechanic identified that a small amount of ammonia had leaked from a worn shaft seal coupling. There was no effect on the environment or the health and safety of personnel. None of the ammonia detectors in the plant displayed elevated concentrations of ammonia.

The compressor was shut down and the seal replaced in accordance with standard practice.

Ammonia release

At about 4:00 p.m. personnel reported the smell of ammonia in a freeze plant. Following up the report, refrigeration mechanics identified two small leaks on pipe fittings. There was no effect on the environment or the health and safety of personnel. Monitoring showed ammonia levels in the plant remained at safe levels well below regulatory limits.

One of the sources was repaired immediately. The second required equipment be taken out of service pending repair.

Workplace injury

A worker suffered an injury to his hand while installing piping underground at the McArthur River mine.

The worker received first aid treatment at the clinic at site. The piping work was halted and the equipment involved was taken out of service pending completion of an investigation.

Reportable release

At 9:30 am a liquid propane distribution hose at the Acid Plant Propane Tank Farm was visually inspected and found to be leaking. Release volume is considered negligible as consumption of propane remained consistent with routine operation during the period.

It is expected that the line deteriorated over time. Repairs were completed by the site plumber. Provincial and federal regulators have been notified.

Ammonia release

A minor leak was discovered on an ammonia storage tank by the solvent extraction facility at approximately 3:00 pm. The area was isolated and maintenance staff notified.

It is expected that a valve on the tank has deteriorated as it was due to be replaced in 2019. Provincial and federal regulators were notified.

Reportable release

During a review of groundwater monitoring data it was noted that a sampling well adjacent to the mill building was showing an increasing trend in uranium concentration. Following further sampling, early indications show that a nearby sump area within the mill has released an estimated 50 m³ of water over the course of the year.

Further investigation is underway and the area will be pumped dry and inspected. Provincial and federal regulators have been notified.

Reportable release

An employee noticed the smell of propane at 10:40 am on November 22nd and the source was determined to be the reverse osmosis propane tank. Tank levels did not indicate any change, so it is expected that the release volume was very small. Corrective Action: Repairs were completed by the site plumber. Provincial and federal regulators have been notified.

Repairs were completed by the site plumber. Provincial and federal regulators have been notified.

Reportable release

At 8:00 a.m., automated monitoring in the reverse osmosis facility at the Key Lake Operation measured high pH readings. In accordance with the facility’s design, the flow of treated water was redirected. Approximately 10 cubic metres of water that was above the high pH regulatory limit was released from the reverse osmosis facility into Horsefly Lake.

Treated water from the reverse osmosis facility was redirected until the pH was back to normal operating range. The incident is being investigated to prevent recurrence. Provincial and federal regulators were notified.

Fire alarm system activation

The Key Lake permanent camp fire alarm system was activated at approximately 6:00 a.m.. The emergency response team (ERT) responded in accordance with emergency procedures and verified that it was a false alarm.

The cause of the false alarm is under investigation and the CNSC was notified.

Ventilation Ducting Support Failure

A clean-air supply ventilation duct in the Key Lake mill separated at one location causing a section of duct to drop and rest on pipes below. 

The area was restricted and the incident is being investigated. Provincial and federal regulators were notified.

Reportable release

Approximately 170 kg of C02 was released from a tank in the solvent extraction valve room. The area has been secured and ventilated and the tank will be inspected and tested before being put back in service.

The cause of the release is being investigated. Provincial and federal regulators have been notified.

Reportable release

A small amount of ammonia was released from valves on the No. 1 ammonia storage tank vapour line, located outside the Key Lake mill facility. 

The area was isolated and repairs have been completed. Provincial and federal regulators have been notified.

Reportable release​

A small amount of ammonia was released from valves on the No. 2 ammonia storage tank vapour line, located outside the Key Lake mill facility. 

The area was isolated and repairs have been completed. Provincial and federal regulators have been notified.

Ammonia release​

The smell of ammonia was detected in the tank farm area near the mill during a routine inspection. Follow-up investigation identified a release of ammonia vapour from a valve. 

The area was secured and the leaking valve was isolated and then repaired. An investigation is under way to determine the cause of the leak.

Sulphur furnace ignition failure  

A small propane explosion occurred within a sulphur furnace in the acid plant at the Key Lake mill during initial start-up procedures. Key Lake’s emergency response team was activated.  No one was injured in the incident. 

An investigation is underway to determine the cause of the incident. Appropriate federal and provincial regulators were notified. 

Transportation incident

A tractor-trailer unit carrying drummed uranium concentrate entered the ditch on Highway 914 south of the Key Lake mill in northern Saskatchewan. No one was injured.  The tractor and trailer remained upright and the load was intact.

The tractor and trailer were removed from the ditch and returned to Key Lake for assessment to ensure the load was secure before continuing the shipment. The incident was reported to regulatory authorities and the cause is under investigation.  

Release of low-grade ore 

A small amount of mineralized waste rock  was released to a site road and to a parking area on the Key Lake mill site from the bucket of a front-end loader. 

The loader was secured to prevent further release and the mineralized waste rock  was collected from the road and parking area and transported back to the ore stockpile. After the material was cleaned up, scans of the two areas confirmed the cleanup was effective. 

Reportable discharge

Manhole overflowed releasing approximately 15 m³ of untreated water.

Sand surrounding the area was removed and actions to repair and test the line were initiated.