A thesis submitted for the degree of Doctor of Philosophy in the Faculty of Science
at the University of the Witwatersrand. / The present thesis is divided into three parts. The study described
in Part I arose out of a request by the Chamber of Mines Mining Research
Laboratory to the National Institute for Metallurgy to undertake a preliminary
study of whether it would be feasible, in Witwatersrand conglomerates, to carry
out rapid delimitation of areas rich in gold and/or uranium at the rock face, a
procedure which would permit areas of rich ore to be removed selectively by
means of the "rock-cutter". The approach adopted in this study was essentially
geochemical, while conventional mineralogical techniques (macro-auto radiographs ,
thin section and polished section analyses) provided a control. The samples were
drawn from the Vaal Reef at Hartebeestfontein and Zandpan and from the Ventersdorp
Contact Reef at Venterspost, and were analysed quantitatively for gold, silver,
uranium, pyrite, muscovite, pyrophyllite, chlorite, quartz, iron, potassium,
nickel, titanium, zirconium and chromium. The intensity of the interrelationships
between the elements and minerals analysed for was examined statistically
by means of correlation covariance and factor analysis programmes written for
an IBM 360/50 digital computer. A sympathetic relationship -- defined as significant
positive correlation (with a correlation coefficient r> 0. 7) -- was found to
exist between gold and uranium in both the Vaal Reef and Ventersdorp Contact
Reef samples. These findings suggest that gold and uranium can be removed
Simultaneously by means of the rock-cutter, and that radioactivity can be used as
an indicator for on-site delimitation of areas rich in gold.
In the course of the study described in Part I, it became evident
that little detailed mineralogical work had ever been done on the phyllosilicates
occurring in the Witwatersrand System. Accordingly, certain phyllosilicates
from Witwatersrand conglomerate bands and other sources were examined in detail,
this study being described in Part II of the present thesis. This study called
for detailed chemical, optical, X-ray crystallographic, infra-red, differential
thermal and thermogravimetric analyses, the results of which are presented. The
findings were examined in the light of variolls classification schemes that have
bep proposed for the phyllosilicates. This investigation revealed the need for a
universally acceptable system of classification for the phyllosilicates, which
should preferably be drawn up under the auspices of the International Mineralogical
Association to avoid the confusion that exists at present.
Part III of the present thesis is devoted to a discussion and description
of various analytical techniques that had to be modified or developed to meet
th8 requirements of the studies described in Parts I and II. The techniques described
include:
(1) An X-ray diffraction method which was developed for the quantitative
analysis of pyrite, muscovite, pyrophyllite, chlorite and quartz in crushed ore
from Witwatersrand conglomerates. This method makes use of novacul iie as an
external standard and of binary mixtures as analytical standards, and had a mean
absolute error of 1. 1 %. This method may be expanded to permit analysis of an
n-component mixture.
(2) A whole rock pressed powder technique of X-ray fluorescence
analysis which was used for the quantitative determination of iron, potassium,
nickel, titanium, zirconium and chromium. This method makes use of internstional
rock standards as external standards.
Six computer programmes used for the computation of the analytical
results and in the statistical and crystallographic calculations are also
presented in Part III. / AC2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/22042 |
| Date | January 1970 |
| Creators | Von Rahden, Herbert, Valentin, Richard |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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