Lithium (Li) is sourced from three major deposit types, being: brines and evaporites, pegmatites and sedimentary rocks.
Brines are saline waters with high concentrations of dissolved salts. Lithium in brines is derived from the erosion of surrounding rocks and hot springs into playas, lakes and salars. However, due to the high altitude of salar deposits, it can take months to years to evaporate and concentrate lithium from brines.
Pegmatites, also one of the sources of lithium brine deposits, are coarse-grained intrusive rock units formed by the crystallisation of magma deep within the Earth’s crust. Lithium is generally concentrated in two main minerals being spodumene and lepidolite. Extraction of lithium from hard rock sources has the advantage over evaporites in that mining process takes days to weeks and therefore can therefore take advantage of increasing market demand more rapidly.
Lithium-bearing minerals have distinct spectral signatures that can be mapped by the HyMap spectrometer. The HyMap spectrometer can survey more than 500km² per day and map sub 1m wide pegmatites. Processed HyMap data has located several new lithium bearing hard rock sources in the Northern Territory and Western Australia, in both arid and vegetated terrains.