Micro-analytical technologies for mineral mapping and trace element deportment

Abstract

Quantifying the texture, mineralogy and mineral chemistry of rocks in the mine environment is required to predict the value of a deposit and maximize extraction efficiency. Scanning electron microscopy supported by recognition of minerals by characteristic X-ray emissions is the preferred mineral mapping method in the mining industry at present. This system is fully mature and supported by highly optimized software. Laser Raman mapping may compete for some of this space in the future. Very coarse scale mineral maps are possible from drill core images but these cannot be used to measure the key parameters required for most mine planning. Trace elements can be highly concentrated in rare minerals so that they are easy to detect but very difficult to accurately measure due to sampling problems, or they may be very dispersed and difficult to detect at all. There are a range of tools available to support trace element deportment and most studies will need to use more than one methodology. The key new development of the last decade is the emergence of laser ablation inductively coupled plasma mass spectrometry for the measurement of most elements at sub-ppm level. There are still many trace and minor elements for which accurate models of deportment are extremely difficult.