Mineralogical imaging of kimberlites using SEM-based techniques

Abstract

Rapid mineralogical identification via energy dispersive spectrometer (EDS) equipped scanning electron microscope (SEM) techniques, is usually used to derive mineralogical images of finely comminuted particles of metalliferous ores. EDS-SEM techniques are shown below to also be suitable to the detailed mineralogical imaging of primary diamonds ores, i.e. kimberlites. However, certain characteristics of kimberlite such as the heterogeneity of the deposit, the relatively large particle size of the ore streams, the fine-grained silicate mineralogy, and the extreme rarity of diamond, present challenges to the imaging of these ores using such techniques. The estimation of standard process mineralogical parameters such as association, liberation, and grade, are therefore also complicated substantially. Potential solutions to these challenges include the presentation of larger samples to the instrument and the use of liberation and grade proxy minerals. Other uses of mineralogically classified images are also discussed.