Cigar Lake Operation

Owner
Cameco Corp.
Client
Alan Auld Engineering
Cost
$50 million CAD
Timeframe
June 2012 — ongoing
Services performed
Site supervision services, consulting, monitoring and on-site design performed by senior engineer and two tunnel inspectors.
Description
Cameco Cigar Lake is the world's highest grade uranium deposit. It is considered one of the world's most technically challenging uranium deposits to mine. The ore body and the ground around has to be bulk frozen prior to extraction of the ore using high pressure water jets. Development of the freeze/production cross-cuts take place beneath the ore body in unstable, soil-like highly weathered and anisotropic rock. A flexible shotcrete lining with longitudinal slots of special yielding elements together with systematic rock bolting were utilized to cope with squeezing ground conditions.
Geology
Highly thermo hydraulically weathered metapelites in form of weak rock and clayey-silty-sandy soils, highly anisotropic, cut with slickensided graphitic planes.
Location
Saskatoon, Canada

Highlights

  • Squeezing ground conditions and highly anisotropic stress conditions
  • Artificial ground freezing
  • Heavily bolted flexible lining with yielding elements
Pocket excavation in unstable ground conditions

Pocket excavation in unstable ground conditions

Installed yielding elements prior to spraying shotcrete