The Cigar Lake uranium deposit, Saskatchewan, Canada

Abstract

The Cigar Lake uranium deposit is exceptional in terms of both tonnage and grade. Geological reserves are estimated at 154 600 t of uranium with an average grade of 7.9%. The richest zone, called the pod, contains 113 000 t of uranium at 12.2%. The surface projection of the orebody would cover an area equivalent to the Champs ElysCes. The Cigar Lake uranium deposit was discovered in May 1981 by Cogema Canada Limited, acting as operator of the Waterbury Lake Joint Venture. The discovery hole was the 13th and last hole of the 1981 drilling campaign. It is interesting to note that the first showing of uranium in the Athabasca Basin was discovered about 40 years ago. However, progress in the development of exploration models was slow and it was not until 1968 that a first uranium deposit, Rabbit Lake, was finally located at the eastern margin of the Athabasca Basin. This discovery was followed the same year by the Cluff Lake deposits in the Carswell structure and since then by several other discoveries. Cogema has encouraged the scientific study of the unconformity-type uranium deposits. Initial studies were compiled in the 1985 Geological Association of Canada Special Paper entitled f i e Carswell structure uranium deposits, Saskatchewan. Similar support was given for the study of the Cigar Lake deposit in both France and Canada. We now have eight manuscripts to present dealing with the main petrological, mineralogical, and geochemical aspects of this deposit. We would like to thank H. Baadsgaard, M. Bernat, G.N. Breit, M. Cuney, Ph. Holliger, T.K. Kyser, J. Leventhal, K.R. Ludwig, C. Hallenstein, A. Meunier, V. Ruzicka, J. Smellie, L. Turpin, B. Velde, E. von Pechmann, and I. Wendt for having reviewed these manuscripts. The contribution of John Clague, former Editor of the journal, is also greatly acknowledged. We also thank FrCdCric Tona, Mineral Exploration Manager at Cogema, and Michel Poissonet, President of Cogema Canada, for their encouragement in having these results published, as well as all the geologists (H. Knipping, P. Caumartin, J. Learn, S. Lavoie, M. Fowler, and J.P. Fouques) whose work provided a solid geological framework. Their assistance and guidance in the choice of study sample material are appreciated. Finally, we would like to thank our joint venture partners: Cameco, Idemitsu, and Kepco for supporting the publication of these manuscripts.