Strategic position on Eastern Bushveld
- Current Resource Defined43.69 Moz 3PGE+Au
- Geology very well understood (lithology, structure, mineralogy)
- Reefs dipping between 8° and 10° westwards
- 3 adjacent operating PGM mines
- Large scale resource
The Garatau Project is in the central sector of the eastern limb, Bushveld Complex. The mining right area is host to PGE mineralisation hosted primarily in two sub-horizontal layers: the UG2 Chromitite (UG2) and the Merensky Reef (MER).
The geology of the project area is well understood as informed by data from an extensive field mapping, diamond drilling, aeromagnetic surveys, geotechnical studies complemented by expert interpretation and modelling.
The MR is present at depths between 280 meters and 1500 meters below surface, with the UG2 reef located between 290 meters and 370 meters below the MR. Bot reefs dip gently at 8 – 10 degrees towards the West.
The MR is a brownish grey, medium-crystalline feldspathic pyroxenite, generally bounded by two chromitite stringers, with the chromitite stringers defining the top and bottom reef contacts. This is considered the normal “wide facies” reef and the thickness typically ranges from 1.8 – 2.2 m. The top chromitite stringer is laterally persistent but the bottom chromitite is more irregular and may be locally absent. The MR is generally overlain by a medium crystalline, locally pegmatoidal, feldspathic pyroxenite (MR hanging wall pyroxenite). The MR footwall is commonly a pegmatoidal feldspathic pyroxenite typically 10 cm thick.
The UG2 is a chromitite layer and varies in thickness from 60 – 80 cm with a sharp top contact and irregular bottom contact. It is a dense cumulate of chromite crystals intergrown with fine interstitial orthopyroxene and/or plagioclase that occur as mottles up to 1.5 cm in diameter. The UG2 normally has up to three thin chromitite stringers (leaders) with widths ranging from 0.1 – 1 cm located within the hangingwall pyroxenite, about 10 – 5 cm above the UG2 chromitite layer proper. They have important geotechnical implications as they form zones of weakness during mining, resulting in ore dilution. The immediate footwall to the UG2 chromitite consist of a pegmatoidal feldspathic pyroxenite which may be absent in places and is in turn underlain by medium crystalline feldspathic pyroxenite. In places, the UG2 may have cm-scale feldspathic pyroxenite or noritic bands referred to as internal waste which results in grade dilution.