Study on the application of spectral γ logging in R?ssing uranium deposit
Domestically,gross gamma-ray well log,coupled with certain amount of core assay validation,is used as the basic method for the uranium resource estimation for years,which needs a variety of correction,such as iron,mud as well as disequilibrium of uranium-radium.Thorium as an'interference'to uranium measurement is mandatory to be deducted correctly from gross gamma.Rössing uranium deposit is a kind of leucogranite-type uranium deposit.Tons of history core assay results show that the Th/U ratio varies along with the ore body strike and dip,as well as with alteration and lithology.Either Th/U constant method or function fitting based on the statistics of core assay analysis is generally applied to deduct thorium from gross gamma log in Rössing deposit.However,spectral gamma-ray logging can be directly used to probe the concentration of radium and thorium of the mineralization section.This paper illustrated the spectral gamma-ray technique to be reliable and of credibility,in the aspects of instrument,field data probing,error analysis between uranium concentration of spectral gamma-ray logging and thorium-corrected uranium content of gross gamma-ray logging,and reconciliation between uranium concentration computed by spectral gamma-ray log and core assay.It was believed that the spectral gamma-ray well logging is more fast and effective than that of gross gamma-ray logging,particularly applicable to the hydrothermal hard-rock uranium prospecting.
uranium explorationhydrothermal hard-rock uranium depositspectral gamma-ray well loggingcore assay reconciliation
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