Tweefontein Hill is situated in the northern limb of the Bushveld Complex where there is a significant change in strike of the Platreef and Transvaal Supergroup footwall rocks. Discontinuous massive sulphide mineralisation attributed to gravitational settling of a magmatic sulphide liquid occurs within this structure. Detailed mapping and structural investigations show that there are two pre-Bushveld ductile deformation events which have resulted in a major south-west plunging fold at Tweefontein Hill. This fold structure is a primary control on the distribution of massive sulphide mineralisation. Subsequent brittle deformation can be correlated with regional structures and has resulted in focusing hydrothermal mineralisation with remobilised platinum group elements into north-south and north-north-east trending faults.
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