|Uranium ore from Cameco’s Cigar Lake underground mine, pictured here, will be processed at the existing McClean Lake mill, located about 70 km (44 miles) northeast of the new mine. (Photo courtesy of Cameco)|
Cameco reported in mid-March that ore production is under way at its Cigar Lake uranium mine in northern Saskatchewan. The mining system and underground processing circuits are operational, and ore is being transported to the McClean Lake mill operated by Areva Resources Canada 70 km northeast of the mine site. Uranium concentrate production from Cigar Lake ore at the McClean Lake mill is forecast to ramp up to design capacity of 18 million lb/y by 2018.
The Cigar Lake project is operated by Cameco and is owned by Cameco (50.025%), Areva (37.1%), Idemitsu Canada Resources (7.875%) and Tepco Resources (5%). Getting the project into production was a long and difficult process. Construction began in 2005, but all underground development areas were flooded in October 2006. The mine was not fully sealed, dewatered and secured until early 2010.
The Cigar Lake deposit occurs at depths ranging between 410 to 450 m below the surface, where water-saturated Athabasca sandstone meets the underlying basement rocks. Due to geological conditions, the deposit and surrounding rock must be frozen to improve the ground stability and prevent groundwater inflows to the mine.
A jet-boring mining method is operated from tunnels in the basement rock below the orebody, using high-pressure water jets to mine-out cavities in the ore. A mixture of ore and water is piped away from the cavities to underground processing circuits, where it is ground and thickened and pumped to the surface for transportation to the McClean Lake mill.
The McClean Lake mill is expected to begin processing the Cigar Lake ore to uranium concentrate by the end of the second quarter of 2014, producing between 2 million and 3 million lb of concentrate before the end of the year.
As of December 31, 2013, the total capital cost of the Cigar Lake project was estimated at $2.6 billion, up from an original 2004 estimate of $450 million.
Cameco’s share of Cigar Lake’s proven and probable reserves is 108.4 million lb of U3O8 at an average grade of 18.3%. Based on reserves as of February 2012, Cigar Lake mine life will be approximately 15 years, with estimated average annual production of 18 million lb/y of U3O8 recovered at the McClean Lake mill. The project will produce less than the average annual production in the early and late years of the planned mine life.