One of the biggest problems in generating realistic geological and alteration models is the lack of consistency in the logging data.
Mine site drill hole data bases typically contain logging data collected over a period of many years. In most cases the logging will have been completed by tens of different geologists. Consistent logging requires a significant level of skill and experience, but this task is generally assigned to the most junior geologists. As a result, there is a large degree of subjectivity in the recognition of basic rock types, and an even greater lack of consistency in correctly identifying alteration mineralogy, particularly when it involves logging RC chips.
Recent advances in analytical techniques and the application of portable analytical devices and spectrometers makes it possible to collect systematic, quantitative geochemical and mineralogical data that is independent of operator bias.
The industry standard for portable short wavelength infrared spectrometers is the Terra Spec 4 Hi-Res, manufactured by Analytical Spectral Devices (ASD). With these instruments it is possible to measure >1000 meters of RC chips or drill core per day. The data are rapidly interpreted using the CSIRO spectral software “The Spectral Geologist”. This takes a lot of the guess work out of logging. Solid solution variations in sericite and chlorite are easily mapped; things that could never be recognised visually. Spectral logging adds a completely new dimension to your mapping and understanding of mineral systems.
Mineral Mapping has a Terra Spec 4 Hi-Res instrument available for hire at very reasonable rates.