HyLogging systems, and the PIMA and ASD field spectrometers (Terraspec, Labspec and Fieldspec), are a generation of analysis instruments which provide rapid and cost effective data on sample mineralogy and on mineral characteristics. Spectral analysis has applications in: - Delineating alteration systems; - Understanding alteration - mineralisation relationships; - Target generation; - Tackling grade control problems; - Identifying overburden/bedrock boundaries. IR technology is ideally suited to alteration mapping, and over recent years spectral analysis has been effectively applied worldwide to mineral exploration and the characterisation of rock alteration mineralogy suites. The important characteristics of field spectrometers include: - Laboratory quality spectral data of minerals, permitting the determination of fine spectral details, such as crystallinity variations and elemental substitution. - An internal light source in most cases, no restrictions on location or time of day; - Each measurement requires no sample preparation (although samples need to be dry); - Spectra are acquired in ~3-60 seconds, allowing the rapid collection of a large number of analyses in a short time frame; - Instant display of spectra on PC/palmtop screen; - Measurements can be made of all types of samples, including diamond drill core, RC and RAB chips, and outcrop and soil samples, and selective measurements may be made of in situ veins, breccia fragments and small-scale alteration zoning (provided that samples are dry).