Work

XCT scanning coupled to mineralogy and chemistry on drill cores from LCT-type granitic pegmatites at Bergby, central Sweden

Year: 2026

Type: article

Abstract: Rapid characterisation of Li-ore minerals in hard-rock deposits can be hampered due to their similarity to common rock-forming minerals. At the Bergby lithium-caesium-tantalum (LCT) type granitic pegmatite field in central Sweden, the main potential Li-ore minerals are spodumene, petalite, and spodumene–quartz intergrowths (SQUI), of which the latter two can be particularly inconspicuous. In this study we test and evaluate the capacity of a novel drill core scanner system to provide rapid, non-destructive mineralogical and geochemical information through X-ray computed tomography (XCT) imaging combined with X-ray fluorescence (XRF) data and traditional mineralogical/geochemical characterisation. A total of 56.79 m of drill core from two pegmatite dykes were scanned. Optical microscopy, laser Raman spectroscopy, and powder X-ray diffraction were used for detailed mineral characterisation and to define five principal Li assemblage types. From this mineralogical characterisation, a customised XCT attenuation model was designed, in which thirteen attenuation intervals were established, enabling the distinction of major and accessory phases. XCT-derived volumes of spodumene and petalite were obtained and employed to calculate Li 2 O concentrations. XCT-based Li 2 O weight percent estimates show strong agreement with inductively coupled plasma mass spectrometry (ICP-MS) geochemical assay data for the most common assemblage types and grades. Discrepancies occur in lithologies with coarse and heterogeneous distribution of ore minerals or in zones containing additional non-ore Li-bearing minerals. The methodology provides robust petalite–spodumene ratios, offering critical input for metallurgical process design. The results demonstrate that the XCT scanning procedure can be a powerful tool for rapid characterisation of pegmatite-hosted Li-ores, as well as additional critical raw materials, delivering volumetric mineral quantification, mineralogical and textural insights, and reliable Li 2 O estimates to complement conventional logging, sampling and assays. This can be applied both during exploration and production stages and also benefits the potential valorisation of additional pegmatite-hosted critical raw materials present in the deposit.

Source: Journal of Geochemical Exploration

DOI: 10.1016/j.gexplo.2026.108122