Canadian Mining Journal

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URANIUM DEVELOPMENT – Update on Cigar Lake remediation

SASKATCHWAN - Saskatoon-based CAMECO reports progress on its phased plan to restore the Cigar Lake uranium project,...



SASKATCHWAN – Saskatoon-based CAMECO reports progress on its phased plan to restore the Cigar Lake uranium project, after a water inflow on October 23, 2006, flooded the underground development.

The project is a joint venture of Cameco (50%), AREVA RESOURCES CANADA (37%), IDEMITSU CANADA RESOURCES (8%) and TEPCO RESOURCES (5%), and is located in the eastern Athabasca Basin.

The first phase of the remediation plan involves drilling holes down to the source of the inflow and to a nearby tunnel where reinforcement is needed, pumping concrete through the drill holes, sealing off the inflow with grout and drilling dewatering holes. Reinforcement of the adjacent tunnel is now complete, and all of the holes required for pouring concrete to seal off the inflow have been drilled. Drilling of four larger-diameter holes required for dewatering is 90% complete.

Regulatory agencies have approved plans to flush sand and fine material away from the inflow area and to pour the concrete plug. The concrete mixture is designed to harden under water and will be poured in successive layers. If the concrete solidifies as planned, it should prevent or reduce water inflows sufficiently to enable mine dewatering. The effectiveness of the plug will not be known until dewatering is underway.

Subsequent phases for remediation will include dewatering the mine, ground freezing in the area of the inflow, restoring underground areas and resumption of mine development. Regulatory approval is required for each phase of the remediation plan.

To ensure a more conservative approach, Cameco and its partners are examining whether an alternative route out of the mine is required prior to beginning excavation in areas at elevated risk of water inflow, and whether the second shaft needs to be completed to provide additional underground ventilation. Completing the second shaft as a priority item, and the delay in completing phase two would set back the planned production startup date from late 2010 to 2011. The decision on the second shaft should be announced by year end, and a revised production forecast will be provided after that.

“In response to the third-party investigations into the water inflow events at Cigar Lake, the regulators have made it clear that we need to demonstrate improvements in our quality culture, said Tim Gitzel, Cameco’s chief operating officer. We agree and are taking concrete steps to address the underlying issues.”

About 285 people are working on site on remediation and construction of surface facilities including the access road, piping infrastructure, load-out building and water treatment facilities.