The In-Place Leaching of Uranium at Denison Mines

Abstract

AbstractAbstractWith to day's soft uranium market and the mining of high-grade open-pit deposits, a new technology to reduce the operating cost to recover relatively low-grade underground reserves of uranium was required.The biological aspects of bacterial leaching of pyritic uranium ore was well known. Blasting technology has advanced to a stage where relatively predictable results as to fragmentation and sizing of ore were possible. Based on this knowledge and the layout and disposition of the Denison orebody, a feasibility study was undertaken to determine the viability of in-place underground leaching of vast deposits of low-grade reserves which were not economically recoverable. In addition to these low-grade deposits, chloric ore not conventionally recoverable because of problems created in the hydrometallurgical plant such as high acid consumption and blinding of the drum filters, was also studied as to bacterial leaching amenability. Encouraging test results have led to a large-scale demonstration using known technology. This technology, developed initially by government labs and refined in practice, has allowed Denison to recover 80 tonnes of uranium from in-place leaching in 1983. Improvements on present methods are being investigated and will continue to be studied in the future. An ambitious research program is planned to optimize fragmentation technology, recovery potential and environmental problems. Acknowledgment is given to the many authors and investigators who have contributed to the development of bacterial leaching as a recovery method for uranium ores.