SJS recently attended a workshop demonstrating the capabilities of the HyLogger™, a tool designed for rapidly capturing detailed mineralogical information from drill core using reflectance spectroscopy.
The workshop was hosted by GSWA, CSIRO and kindly supported by FLSmidth, responsible for developing, promoting and distributing HyLogger™
The HyLogger™ system comprises of integrated visible and near-infrared (VNIR), shortwave infrared (SWIR), thermal infrared (TIR) spectrometers, and a high-resolution camera. It is designed to improve knowledge and understanding of the mineralogy of drilled targets, and to obtain an objective, rather than a subjective, view of the mineralisation. This in turn increases the value of drill core, and can be cost effective in the long term, by pinpointing mineralised sections of core to be assayed, and potentially reducing costs associated with further drilling.
The course introduced the HyLogger™ and the process of logging, data extraction and interpretation, using “The Spectral Geologist” (TSG™) software (available from The Spectral Geologist website). HyLogger™ samples the core at cm scale, resulting in a large dataset and high sample density. Assay data can be added to TSG™ and compared to mineral abundance.
TSG™ software compares the measured spectra with a library, which the operator constrains by location. Once quality assurance and control procedures are verified, data is available to view alongside high quality photographs of the core, automatically stitched together. The depth of the absorption or reflection feature within the spectra relates to the abundance of that particular mineral in the core.
During the day we looked at some case studies of core from three Western Australian deposits, and compared our logging to the data from the HyLogger™. All delegates agreed that viewing the data prior to logging would have been hugely beneficial in determining the mineralised domains, especially as the HyLogger™ can pick up on minerals not visible to the logging geologist with hand lens. For example, we all found it hard to distinguish apatite in the core, which is the major host mineral for REE’s in that particular example. The HyLogger™ was also able to pick up on alteration in black shales, and muscovite and serecite in clay zones, which are not visible.
In conclusion, the HyLogger™ is a useful tool in the “geologists toolbox” and there is a place for it alongside geochemical analysis and traditional logging. Delegates discussed the fact that it probably creates too much data for an exploration environment, and a hand held spectrometer such as the Portable Infrared Mineral Analyser (PIMA) or ASD’s TerraSpec® Halo Mineral Identifier would be more useful in such a case. However, utilizing the HyLogger™ on large drilling programmes could be useful in domaining mineralisation, and would ultimately increase knowledge and save money in the long term.