The South Junction deposit of St Barbara Mines Limited was discovered in 1989 by the geologists of Ross Atkins Mining.
The deposit occurs in the lower part of the Gabanintha Formation of the Lukes Creek Group in the Mt Magnet - Meekatharra greenstone belt. Country rock is predominantly talc-chlorite schist. Gold mineralisation is associated with north-south shear zones, quartz-carbonate-fuchsite alteration of the ultramafic rocks and in particular close to deeply weathered quartz-albite porphyry. For a detailed description of the geology of the South Junction Deposit see Fiala (1992).