Sulphide and chromite mineralisation occurs within the Uitkomst Complex, a Bushveld-age, layered, mafic-ultramafic intrusion, which concordantly intrudes dolomite/chert of the Malmani Subgroup and shales/quartzites of the Timeball Hill Formation. The Uitkomst Complex, which lies unconformably on an Archaean basement, is a north-west/south-east tubular shaped body which outcrops in the Slaaihoek Valley for approximately 9 kilometres before dipping at 4º below an escarpment where it has been drilled down-dip for another 4 kilometres and is still open-ended to the north west.
From the base to top, the stratigraphy of the Uitkomst Complex comprises the Basal Gabbro Unit (up to 15 metres thick), the Lower Pyroxenite Unit (average 35 metres), the Chromititic Peridotite Unit (30 to 60 metres), the Massive Chromitite Unit (up to 10 metres), the Peridotite Unit (330 metres), the Upper Pyroxenite Unit (65 metres), the Gabbronorite Unit (250 metres), and the Upper Gabbro Unit (50 metres). The complex and surrounding sediments are intruded by numerous diabase sills up to 30 metres in thickness.
Apart from the now mined-out Massive Sulphide Body (MSB), situated at and below the base of the Uitkomst Complex, there are three main economic sulphide mineralised zones:
-The Basal Mineralised Zone (BMZ) within the Basal Gabbro;
-The Main Mineralised Zone (MMZ) occurring within the Lower Pyroxenite Unit;
-The Chromititic Peridotite Mineralised Zone (PCMZ) wh ........
