Mapping of carnallite along with semi-quantitative estimation of potassium content of drill cores using hyperspectral imagery

Abstract

ABSTRACTReflectance spectra and hyperspectral images of carnallite, halite, and anhydrite samples from the Mboukoumassi sylvite deposit, Congo, were obtained using an ASDTM spectrometer and a HySpexTM imager, respectively. The spectral absorption features of the ore mineral, carnallite, at 999, 1076, 1206, 1232, 1763, and 1970 nm are highly reproducible and distinct from absorption features of the gangue minerals, halite and anhydrite. The intensity of the approximately 1200 nm absorption feature can be used to map the spatial distribution of carnallite in drill core. We also established an empirical relationship between potassium content estimated through X-ray fluorescence (XRF) measurements and absorption intensity at approximately 1200 nm. Based on this empirical relationship, the potassium content of a core surface was mapped. This technique provides more detailed estimates of potassium content and its spatial distribution in core samples than possible by point sampling, and this is beneficial in assessing the resource potential sylvite deposits.