Cigar Lake mine, Canada

1st September 2017 By: Thabi Shomolekae - Creamer Media Senior Research Assistant and Reporter

Cigar Lake mine, Canada

Name: Cigar Lake mine.

Location: The mine is located in the Athabasca basin, north of Saskatchewan in Canada.

Holding and Controlling Company: Cigar Lake is owned by the Cigar Lake Joint Venture (CLJV) partners – Cameco Corporation (50.025%), Areva (37.1%), Idemitsu Canada Resources (7.875%) and TEPCO Resources (5%).

Brief Description: Cigar Lake is the world’s highest-grade uranium producing mine, with mineral reserve grades more than 100 times the world average for uranium deposits.

The mine site contains all the necessary services and facilities to operate a remote underground mine, including personnel accommodation, access to water, an airport, site roads and other necessary buildings and infrastructure.

Brief History: The Cigar Lake uranium deposit was discovered in 1981.
Full-scale construction began in 2005 with production originally planned for 2007, but development was suspended following water inflow in April and October 2006, which flooded the mine. A second inflow occurred in 2008 after sealing the initial inflow.

Remediation efforts continued and in October 2009 Cameco successfully sealed the August 2008 inflow, and the underground workings were dewatered in February 2010. Safe access to the 480 m and 500 m levels was restored and the refurbishment of underground mine systems and infrastructure was completed in 2011.

With the mine re-entry and remediation milestone achieved, construction of the permanent underground infrastructure began and was substantially completed in 2013. Staged commissioning of the jet boring system machine and supporting underground circuits began shortly thereafter, with the first commissioning cavity mined in barren rock in October 2013 and the first ore cavity mined in December 2013.

The first shipment of ore slurry to McClean Lake mill began in March 2014 and the first yellowcake was packaged in October 2014.
Commercial production was declared in May 2015, with operations now focused on achieving the production ramp-up to full nameplate capacity.

Products: Uranium.

Geology/Mineralisation: The Cigar Lake deposit is located west of the eastern margin of the Athabasca basin. It is an unconformity related uranium deposit, occurring at the unconformity contact between rock of the Athabasca Group and underlying lower Proterozoic Wollaston Group metasedimentary gneiss and plutonic rocks.

Cigar Lake shares many geological similarities with the Key Lake, McClean Lake, Collins Bay and McArthur River deposits, including general structural setting, mineralogy, geochemistry, host rock association and the age of the mineralisation. However, the Cigar Lake deposit is distinguished from other similar deposits by its size, high grade, the intensity of its alteration process, and the high degree of associated hydrothermal clay alteration.

The Cigar Lake deposit is similar to the McArthur River deposit in that sandstone overlies the basement rock and contains large volumes of the water at significant pressure, however unlike McArthur River, this deposit is flat lying.

The deposit is about 1.950 m long, 20 m to 100 m wide, and ranges up to 13.5 m thick, with an average thickness of about 5.4 m. It occurs at depths ranging between 410 m and 450 m below surface.

Two distinct styles of mineralisation occur within the Cigar Lake deposit: high-grade mineralisation at the unconformity mineralisation, which includes all of the mineral resources and mineral reserves, and fracture controlled, vein-like mineralisation, which is located either higher up in the sandstone (“perched” mineralisation) or in the basement rock mass.

The body of the high-grade mineralisation at the unconformity contains the bulk of the total uranium metal in the deposit, and currently represents the only economically viable style of mineralisation, in the context of the selected mining method and ground conditions. It is characterised by massive clays and high-grade uranium concentrations.

Reserves: Total proven and probable reserves as at December 31, 2015, were estimated at 601.8-million tonnes grading 16.70% uranium oxide (U3O8).

Resources: Total indicated resources as at December 31, 2015, were estimated at 20.3-million tonnes grading7.38% U3O8.

Total inferred resources as at December 31, 2015, were estimated at 284.7-million tonnes grading16.43% U3O8.

Mining Method: Cigar Lake uses a jet boring mining system (a non-entry mining method) because of the challenges associated with mining the deposit, including control of groundwater, weak rock formations, radiation protection, water inflow and relatively thin, flat-lying mineralisation.

Major Infrastructure and Equipment: Cigar Lake includes an underground mine with two shafts, underground tunnels; a surface and underground pumping system installation; freeze plants and brine distribution equipment; surface freeze pads; water supply, storage and distribution for industrial and potable water and fire suppression; as well as an electrical power substation, which is connected to the provincial electricity grid by a 138 kv overhead power line.

Cigar Lake also has generators on standby in case of power outages.

The mine also has waste-rock stockpiles and an ore load-out facility. Cigar Lake’s ore is processed at the McClean Lake mill, operated by Areva.

Prospects: The modification and expansion of the McClean Lake mill have been completed and the mill now has sufficient capacity to produce 18-million pounds a year of U3O8 from Cigar Lake.

Cameco is mining the eastern part of the Cigar Lake orebody (Phase 1). Meanwhile, surface delineation drilling is continuing for the western portion (Phase 2).

Contact: Cameco investor relations director Rachelle Girard

Contact Details:
Cameco
Tel +1 306 956-6403
Fax +1 306 956-6318
Website https://www.cameco.com