The Tharisa Mine is situated on the southwestern limb of the Bushveld Complex and is underlain by the Middle Group (‘MG’) and Upper Group (‘UG’) Chromitite Layers straddling the boundary between the Marikana and Rustenburg facies. The MG Chromitite Layers outcrop is on the property, striking roughly east to west with a gentle change in strike to northwest-southeast in the far west. The layers dip at between 9° and 15° to the north. Towards the western extent of the outcrop, the dip is steeper. The stratigraphy typically narrows to the west and the dip steepens. The dip typically shallows out at depth across the extent of the mine area.
The MG Chromitite Layer package consists of five groups of Chromitite Layers, being the MG0 Chromitite Layer at the bottom, followed by the MG1 Chromitite Layer, the MG2 Chromitite Layer (sub-divided into C, B and A Chromitite Layers), the MG3 Chromitite Layer and the MG4 Chromitite Layer (sub-divided into 4(0), 4 and 4A Chromitite Layers). The layers between the Chromitite Layers frequently include stringers or disseminations of chromite. The MG Chromitite Layers at the Tharisa Mine are a typical stack of tabular deposits.