A temporary halt to jet boring at Cameco's Cigar Lake uranium mine in northern Saskatchewan has forced the company to revise its ore production target date.
Cameco said yesterday it is stopping some work at the mine after discovering that ground freezing used to prevent water from entering the mine has not advanced as quickly as expected in some areas.
"Based on early indications from our assessment we expect the production schedule could shift by a couple of months. Although a minor change to the schedule, it means ore that was expected to be milled at the end of the year, will shift into early 2015 thereby affecting our 2014 production target," the company said.
Cameco said it will provide an update to its 2014 production target in its second quarter results on 31 July when the assessment is complete.
Cameco is the majority owner and operator of Cigar Lake, with a 50.025% stake. Areva Resources Canada Inc, Idemitsu Canada Resources Ltd and Tepco Resources Inc own, respectively, 37.1%, 7.875% and 5%. Ore from Cigar Lake will be processed at the McClean Lake mill, which is majority owned and operated by Areva.
Ground freezing issues
Ore production started at Cigar Lake earlier this year after years of delays due to flooding at the mine. The deposit occurs at depths ranging from 410 to 450 metres below the surface where the water-saturated Athabasca sandstone meets the underlying basement rocks. To prevent water from entering the production areas of the mine and to help stabilize weak rock formations, the ore zone and surrounding ground is being frozen by circulating a brine solution through cased bores drilled from both surface and underground.
As part of the ongoing commissioning process, Cameco has been assessing the current state of ground freezing at Cigar Lake.
"We have determined that freezing has not advanced as quickly as expected in some localized areas of the mine. Given that the McClean Lake mill has not yet started processing Cigar Lake ore, we have decided to temporarily stop jet-boring at Cigar Lake to allow the ore body to freeze more thoroughly in these areas. The additional freezing will allow more continuous production at the mine once the mill is operational," Cameco said.
The company's long-term annual production target of 18 million pounds (8,164 tonnes) U3O8 by 2018 will not be impacted, it said.
Researched and written
by World Nuclear News