Abstract
M.Sc. (Geology)
The Klipwal gold deposit is a low temperature, hydrothermal vein
type deposit. Mineralization is associated with the Klipwal shear zone,
which is in the sedimentary rocks of the upper Mozaan group, of the
Pongola Sequence.
A close correlation was found between the presence of gold and
arsenopyrite. The sulphides in the shear zone are associated with
the iron-poor type of chlorite.
The range in temperature estimated for the Klipwal ore deposit is
approximately 350°C to 400°C. The lower temperature was estimated
from the arsenopyrite-pyrite-pyrrhotite geothermometer and the upper
from the pyrrhotite-pyrite analyses.
The original hydrothermal fluids were probably of a reducing nature,
and some minor sericitic alteration was thought to have taken place.
It was found that 74 percent by volume of the native gold was in
fact associated with, or enclosed in the coarse-grained sulphides,
pyrite and arsenopyrite. 19 percent by volume of the gold was either
in the form of free gold or attached to the edge of a sulphide and
7 percent by volume of the gold is associated with cracks in the
sulphides. These statistics, as well as the information concerning the size of
the gold grains is of utmost importance as far as the recovery and
beneficiation of the ore is concerned.