Efficacy of Hyper-Core-Logging in Uranium Exploration: An Investigation From Kaladgi Prospect, India

摘要

Given its importance as an energy resource, uranium is, globally, one of the most sought after natural resources.. Search for uranium deposit is often complex due to the very specific conditions for its enrichment. Identifying pathfinder minerals and elements that can be used as a proxy for U enrichment is one of the critical aspects of uranium exploration. Typically, prospecting is carried out by tedious and time consuming techniques of mineral identification and geochemistry.. In this study, a spectroscopy-based approach involving analysis of electronic transitions (of U, Nd) and molecular vibrations (Al/Fe/Mg-OH) in reflectance spectra of core samples is attempted to identify mineralization. The hyperspectral image cube of cores was used to map the spatial distribution of U-mineralized zones. It is evident from the results that sericite and Mg-chlorite are the main alteration minerals with spectral absorptions at 2348, 2205, 233 nm respectively that are correlated with U enrichment. U absorption (690 nm) and Nd absorption (746, 801 nm) are very sharp and have narrow bandwidth (20-30nm). It is observed that there is positive, linear correlation $(mathrm{R}^{2} =0.83)$ between the uranium concentrations and depth of absorption at $0.690 mu mathrm{m}$. Similarly, the absorption depths of U and Nd also correlate positively $(mathrm{R}^{2} =0.85)$ thereby indicating a possible genetic relationship. Finally, the spatial mapping of uranium in core samples points to localization around fracture-controlled fluid migration pathways. It is concluded that the proposed methodology can be used as a rapid exploration technique for some epigenetic uranium deposits that exhibit similar geochemical environment.