Characterization of the Kintyre uranium ore and optimization of the leaching process

Cameco's Kintyre uranium project, located in the Eastern Pilbara region of Western Australia, is currently in the final stages of the prefeasibility study. This study is being led from Cameco Australia's Perth office, with assistance from the Cameco Technology and Innovation (CTI) and Major Projects groups. Cameco teams have supported the development of this project on all activities including geology, mineral resource classification, mining, metallurgy, geo-environmental, and design engineering. This paper focuses on the ore properties of this deposit, and how it has influenced the process flow sheet option selection. The Kintyre deposit mineralisation is defined as basement hosted vein type uraninite/coffinite, which is primarily comprised of dolomite, magnesite and calcite. The carbonate content of the ore is high relative to the uranium content (U/CO3 < 5%, and as such, poses challenges with regards to conventional acid leaching, as demonstrated by test work performed by the Cameco Technology and Innovation - Research Centre (CTI - RC) in Port Hope, Canada. Extensive test work has been completed by the CTI - RC and others in efforts to pre-concentrate uranium and to simultaneously reduce carbonate content by means of gravimetric, flotation and radiometric sorting methods. It has become apparent from these metallurgical campaigns that the uranium and carbonate mineralisation's are closely interlinked, and that carbonate is only effectively removed on a mass basis. As a result, acid consumption across all Kintyre zones remains very high, such that it has a significant economic impact on the project. For this reason, the alkali leach path has been investigated as a viable alternative by the Cameco project team. This paper will present the outcomes of this trade-off study in terms of technical, operability and relative economic standpoints. (author)