Hyperspectral Radiometry to Estimate the Grades of Iron Ores of Noamundi, India – a Preliminary Study

This paper present the results of a preliminary study to assess the potential of the visible, NIR and SWIR energy of the EMR in differing iron ores of different grades in a rapid manner using hyperspectral radiometry. Using different iron ore samples from Noamundi mines, Jharkhand, India, certain spectro-radiometric measurements and geochemical analysis were carried out and the results have been presented. It was observed that the primary spectral characteristics of iron ores lie in the 850 to 900nm region. Various methods to evaluate the parameters for each curve such as: the radius of curvature of the maximum absorption trough, position of the trough with respect to wavelength in the NIR region and distance of the trough from a reference line, were adopted. Comparison of the spectral parameters and the geochemistry of the samples indicates that the depth of absorption (distance of trough from a reference line) in the NIR region for a sample has a strong positive correlation with the iron oxide content in the sample, while the radius of curvature of the absorption trough has a strong negative correlation with the iron oxide content. Such strong correlations indicate that hyperspectral radiometry in the visible and NIR regions can give a better estimate of the grade of iron ore. This study has demonstrated that generation of empirical models using hyperspectral radiometric techniques is helpful to quantify the grade of iron ores with limited geochemical analysis.