Mid-infrared reflectance measurements using a DPSS OPO for on-line determination of mineralogy for ore sorting and characterisation

Efficient ore sorting depends critically on the level of discrimination offered by the sensor. Photometric sensors at visible wavelengths often require the use of at least two wavelength bands to provide adequate discrimination particularly if there is similarity between the ore and gangue or if there is a range of ore components. Mid-infrared reflectance bands can increase selectivity and enhance sorting of complex ores. In particular, weak absorption features in remission spectra are valuable for discriminating ore and gangue. CSIRO is developing a broadly tunable OPO as a source of mid-infrared light to facilitate the development of new sensors for ore sorting and mineral characterization.