Resources
The Bushy Park resource totals 10.9 Mt of Indicated and Inferred resources at 3.78% Zn and 0.15% Pb. The Mineral Resource Statement for the Bushy Park Project declared in terms of JORC Code (2012) is presented in Table 2 and is reported using a 1.5% Zn cut-off grade.
The Resources remain open at depth.
Figure 16: Regional geology of the Griquatown area
Geological Setting and Mineralisation
The Bushy Park deposit is an epigenetic Pb-Zn deposit, hosted by Late Archean stromatolitic carbonates of the Transvaal Supergroup (Figure 16). It is the second largest carbonate-hosted Pb-Zn deposit in the Griqualand West region and is widely regarded as being one of the oldest Mississippi Valley-Type (MVT) Pb-Zn deposits in the world.
The mineralisation is intimately associated and genetically linked to intensive hydrothermal dissolution and collapse brecciation of the host dolomites by metalliferous brines that entered the carbonate platform from below. The brecciation extends from surface to a current drill limit of 400 mbs, and remains open at depth. Sphalerite and galena are the dominant sulphides and occur as coarse crystalline randomly distributed open space fill in the dolomite spar matrix.
Outcrop of the deposit can be traced over an area of 1,600m by 600m that can best be described as an inverted bowl that widens with increasing depth (Figure 16). Drilling has outlined five discreet mineralised zones in the "inverted teacup" shaped structure, namely the Upper East Zone, Lower East Zone, West Zone, North Zone and Central Zone. Oxide mineralisation is present near surface (20 mbs to 30 mbs), particularly in the Upper East Zone. Individual mineralised breccias dip steeply outwards with an indicated depth in the order of 300 mbs in the Eastern Zone and 250 mbs in the Western Zone that remains open at depth, while the Central and Northern Zones do not extend to the same depth. The individual zones are continuous, although the Northern Zone is narrow and more irregular.
