Cameco updates on Cigar and Rabbit Lakes

At Cigar Lake, Cameco says it is maintaining the previously announced expected production restart date. Construction was about 60% complete when the mine experienced a rockfall causing a flood of the underground development in October 2006. Site crews continue to make progress on the remediation plan and we believe that the water inflow has been essentially sealed off. The next major milestone is dewatering the mine.

The concrete barrier plug has been completed after pouring approximately 1,000 m3 of concrete in the tunnel in the vicinity of the original inflow and grouting around it to seal it off. Cameco poured an additional 1,000 m3 of concrete behind the concrete barrier plug and up into the area above the rockfall where the water inflow began. Crews are now in the final stages of grouting above the inflow area and filling the drill holes used in the remediation process.

A preliminary test of the effectiveness of the plug and sealed rockfall area is planned by drawing down the water level in the shaft to an intermediate stage and measuring the water inflow. The company expects to complete this test before the end of February. The plug and seal will be considered effective if the total mine water inflow is limited to a rate considered safe for mine re-entry. Dewatering is planned to proceed after the plug and seal are proven to be effective.

Prior to dewatering, Cameco will complete a geotechnical assessment to determine if depressurisation, reinforcement or other precautionary measures are necessary in two other areas of the mine. To ascertain this, a number of holes are being drilled to assess the pore water pressure, as well as rock quality and structure in these two areas. Five of six holes have been completed and results from this assessment are expected to be available in the first quarter of 2008. Cameco can then assess if any additional remediation is required in these areas.

In addition to the technical work, Cameco needs to complete the corrective actions it committed to do following the root cause investigation, as well as receive certain regulatory approvals. Cameco must have all these activities completed before applying for regulatory approval to dewater. Accordingly, the company is targeting completion of dewatering in the second half of 2008.

The Canadian Nuclear Safety Commission (CNSC) announced, on December 3, 2007, it had amended the construction licence for the Cigar Lake project. The licence will be valid for two years until December 31, 2009. Subsequent amendments to the construction licence will be required to complete remediation and resume pre-flood underground construction and development activities.

Construction activities currently underway at the site include mine ventilation fans installation on surface, the slurry load-out facilities and surface pipelines.

The expected production startup date continues to be 2011 at the earliest, as previously announced. Cameco says it “will be able to provide a firmer production startup date after the mine has been dewatered and the condition of the underground development has been assessed and the findings incorporated in the new mine development and production plans.”

As announced in late November 2007, Cameco’s Rabbit Lake underground mine experienced increased water inflow and mining was suspended. Currently the amount of water entering and leaving the mine is essentially in balance and site crews are in the process of permanently sealing off the affected area. They have only used a maximum of about 4% of the designated underground storage capacity. Planned upgrades to the water handling system were completed in the first week of December well ahead of schedule.

Crews have finished pouring four concrete barriers, or bulkheads to seal off the area from increased water inflow. Two bulkheads were built on the 90-m level and two on the 105-m level. Cameco expects it will take three to five weeks for the concrete in the bulkheads to cure and to complete the associated grouting of the seal and says it “will not start mining until [it has] sufficiently curtailed the water inflow, to re-establish an adequate margin of water handling capacity.”

The company has determined that the additional water is entering the area through a decades-old, exploration drill hole and is in the process of preparing to plug the drill hole.

In 2007, Cameco has produced 4 Mlb of uranium at Rabbit Lake which is the estimated annual production for the year. It will reassess 2008 production and provide an updated forecast when mining and milling plans are finalised.