Cigar Lake celebrates operations

Thursday, 24 September 2015

Cameco and Areva have officially marked the start of production at the Cigar Lake uranium mine and McClean Lake mill in northern Saskatchewan. The mine has been in commercial operation since May.

Tepco, Areva Resources, Cameco and Idemitsu join economy minister Bill Boyd in the ribbon-cutting ceremony (Image: Cameco)

Mining at Cigar Lake began in March 2014, nine years after construction began. The first packaged uranium concentrate from the mine was produced at the McClean Lake mill in October 2014 and the mine was declared in commercial operation in May.

Cigar Lake's high-grade uranium deposit - 234.9 million pounds U3O8 (90,400 tU) of proven and probable reserves averaging over 17% U3O8 - make it the world's second-largest high-grade uranium deposit after McArthur River, also in northern Saskatchewan. However, mining the ore has been technologically challenging. Located at depths of 410 metres to 450 metres below the surface, the orebody is at the boundary between dry basement rock and water-bearing sandstone. This means that the ore zone and surrounding ground must be frozen before mining to prevent water from entering the mine workings and to stabilize weak rock formations.

The ore is removed by jet boring, using a high-pressure water jet to mine out cavities in the frozen ore. The mixture of ore and water is then pumped to underground grinding and processing circuits. Thickened ore slurry is pumped to the surface and transported in tanker trucks 70 kilometres to the McClean Lake mill where it is processed into uranium concentrate.

Cameco president and CEO Tim Gitzel and Areva senior vice president for mining and front end business Olivier Wantz welcomed dignitaries including Saskatchewan's economy minister Bill Boyd and community leaders to a ribbon-cutting ceremony at the mine. Gitzel paid tribute to those who had worked to bring "this rich and challenging deposit" into production. "This achievement took 10 years, great perseverance and technical creativity, and I commend the many people who contributed," he said.

Production on target

So far this year, 6.1 million pounds U3O8 (2346 tU) has been processed and packaged from Cigar Lake ore. This means that Cigar Lake has already achieved the lower threshold of its 2015 production target of 6 million to 8 million pounds U3O8 (2308 to 3077 tU). Cameco said that it is now reviewing the target for the year and will provide an update in its next quarterly report.

The companies warned that volumes may not increase in a linear fashion as mine production ramps up to the full capacity of 18 million pounds U3O8 (7000 tU) by 2018. "To ensure the most efficient operation of the mine and mill throughout the year, we expect to continually manage ore supply and, therefore, may halt and resume mining several times during a quarter without impacting planned annual production," they said.

Cigar Lake is owned by Cameco (50.25%), Areva Resources Canada (37.1%), Idemitsu Canada Resources (7.875%) and Tepco Resources (5.0%) and is operated by Cameco.

The McClean Lake mill is owned by Areva (70%), Denison Mines (22.5%) and OURD Canada (7.5%) and is operated by Areva. The mill has been upgraded to enable it to process Cigar Lake's high-grade ore without dilution, and expansion and construction activities that will enable it to produce up to 24 million pounds U3O3 (9200 tU) per year are slated for completion in 2016.

Researched and written
by World Nuclear News