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TitleGeophysical logging methods for uranium geology and exploration
AuthorMwenifumbo, C J; Mwenifumbo, A L
SourceGeological Survey of Canada, Technical Note no. 4, 2013, 47 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf
Subjectsgeophysics; economic geology; mineral deposits; mineral occurrences; uranium; mineralization; exploration methods; exploration; seismic exploration; geophysical logging; gamma ray logging; gamma-ray surveying; gamma-ray spectrometers; boreholes; geophysical surveys
Illustrationstables; models; schematic diagrams; spectra; logs
ProgramGEM: Geo-mapping for Energy and Minerals, Uranium
Released2013 11 19
AbstractIn the uranium mining industry, borehole logging is a basic tool in the exploration and delineation of uranium deposits. Whereras gamma-ray logging is recognized as one of the most effective techniques for delineating uranium mineralization and estimating uranium ore grade, there are several other methods that provide additional information on the stratigraphy, lithology, structures, and alteration associated with mineralization. These include resistivity, induced polarization, sonic P-wave velocity, density, and temperature.
This technical note provides a brief overview of uranium deposit types and describes at a very basic level the physical principles underlying various borehole-logging methods, equipment, data-acquisition procedures, and log interpretation. A few field case examples are presented. It also provides information on the calibration protocols for gamma-ray logging systems and calibration facilities that ensure reliable logging and interpretation are achieved.
Radioactivity occurs when particles and gamma rays are emitted as a nucleus spontaneously disintegrates. During radioactive decay, alpha particles, beta particles, and gamma rays are emitted. In uranium exploration the focus is on the gamma rays. Though there are three major naturally occurring uranium isotopes, 238U, 235U, and 234U, 99.3% of natural uranium is 238U. Therefore, assuming the parent product is 238U, it decays by emitting beta particles, alpha particles, and gamma rays to its final state of lead-206 (206Pb). The gamma rays that are detected in uranium exploration are from its daughter products, lead-214 (214Pb) and bismuth-214 (214Bi) and not from the parent 238U.