Cigar Leach Hydrogen Mitigation Project
Process Hazard Analysis, Feasibility Study, Basic and Detailed Engineering, Commissioning
Orano Canada Inc. (AREVA Resources Canada Inc.)
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Saskatchewan, Canada
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May 2013 – September 2014
15-month condensed schedule from initial PHA to commissioning.
Leaching circuit upgraded to process high-grade uranium ore.
Project completed on-schedule and on budget with excellent safety record.
Challenges
- Orano’s McClean Lake facility is an existing uranium processing plant located in Northern Saskatchewan, Canada.
- As a result of changing the uranium ore feed to a high-grade material, Orano’s laboratory testing program identified in the potential risk hydrogen evolution during leaching.
- As a consequence, to hydrogen evolution, Orano became concerned that the existing leaching equipment may not be equipped with adequate safeguards to manage the hydrogen, which posed a safety risk.
Solutions
- Orano approached Hatch to assist with evaluating the design modifications for the McClean Lake leach circuit to ensure that it would be able to safely process the Cigar Lake high-grade uranium ores.
- Hatch’s High Pressure Metallurgy (HPM) practice commenced support with a process hazard assessment (PHA) review with the McClean Lake operations team, including process, operations, maintenance and engineering members.
- The project required several trade-off studies to determine the best solutions to repurposing the existing process equipment and resolving the hydrogen concern.
Highlights
- The results of the PHA resulted in HPM completing a feasibility study (FEL3) and immediately progressing to basic engineering and detailed engineering (FEL4) for the proposed circuit upgrades.
- Commissioning of the upgraded leach circuit was achieved in September 2014.
- This was a brownfield, schedule driven project that included repurposing of existing process equipment, limited space for new process equipment, demolition of existing infrastructure, and effective design considerations to help optimize the overall schedule.
- The modifications to the process equipment included:
- Upgrading seven leach vessels with new agitators to provide adequate solid suspension and blending.
- Design enhancements to enable slurry feed forward control.
- Installation of hydrogen and oxygen analyzers.
- Installation of dilution air and vent gas exhaust systems.
- Installation of emergency back-up systems including repurposed diesel generators, uninterrupted power supply, and a passive nitrogen purge system.