A SUMMARISED MINERAL PROFILE OF THE PROVINCES
IN SOUTH AFRICA
Co-ordinated by
C.J. VORSTER
Edited by
E.C.I. HAMMERBECK and M.G.C. WILSON
COUNCIL FOR GEOSCIENCE
1
INTRODUCTION
This is a brief presentation on the mineral potential of the Provinces in South Africa as
part of the Regional Industrial Location Strategy (RILS) study. This document is not
considered a planning document but a mere summary of what is available and statistics
contained in it are now dated as it was compiled in the mid 1990s. For more updated
production statistics, the interested reader is referred to the South African Minerals
Industry book which is published annually by the Minerals Bureau of the Department of
Minerals and Energy. For more detail on the mines and deposits, refer to the Council for
Geoscience’s Handbook 16 entitled The Mineral Resources of South Africa which was
published in 1998. Comments in italics have been added recently.
The geology underlying the Provinces determines the location, types and economic
potential of the various mineral deposits, whilst the exploitation of these deposits relies
on the local availability of water, infrastructure, and political stability, as much as it
relies upon local and overseas investments and markets. The accompanying maps
indicate the location of the most important minerals currently being exploited in the
Provinces.
Mineral production and sales figures in the text were provided by the Minerals Bureau of
the Department of Minerals and Energy.
For planning purposes, more detail is available from the Council of Geoscience in the
form of some standard- and special, geological, metallogenic and mineral maps (1:1 000
000, 1:250 000), as well as comprehensive reports and profiles on mineral deposits.
These can be generated in the form of special- and custom made maps and reports on
demand from the Council's modern, comprehensive databases, e.g. SAMINDABA (the
South African Minerals Deposits Database), COAL (the South African Coal Database),
COREDATA (the South African Borehole Database) and SAGEOGIS (South African
Geological Geographic Information System).
2
A SUMMARISED MINERAL PROFILE OF GAUTENG
By JH Strydom, Council for Geoscience
1. INTRODUCTION
The information on the mining activities undertaken in Gauteng and given in this
document were obtained from: 1. SAMINDABA mineral deposits database of the Council
for Geoscience, 2. The Regional Office Gauteng - Minerals and Energy, 3. The Mineral
Economic Directorate (Minerals Bureau), 4. The Diamond Board and 5. The Chamber of
Mines.
Issues that have been addressed include: 1. Commodities currently being mined in
Gauteng, 2. Number of working mines, 3. Associated geology and 4. Unexplored
resources.
2. GOLD, SILVER, PGM's, URANIUM OXIDE AND SULPHUR
The silver, platinum group minerals (PGM's), uranium oxide and sulphur minerals
exploited in Gauteng are associated with the Witwatersrand gold deposits and they are
thus discussed together.
Although gold has been mined continuously in Gauteng for the last 116 years it still
contributes overwhelmingly towards the mining activity of the province. Gold occurs in
the sediments of the Witwatersrand Supergroup. These sediments were deposited in a
large basin and mining is taking place in a number of distinct goldfields, stretching from
the East Rand Goldfield in the east, through the Central Rand Goldfield, the West Rand
Goldfield and most of the West Wits Line Goldfield towards Carletonville in the west. The
basin extends into the North West Province where the remaining part of the West Wits
Line Goldfield and the Klerksdorp Goldfield were developed as well as into the Free State
where the Free State Goldfield developed. Most of the gold mines in Gauteng are in
advanced stages of declining gold production. Production costs are generally very high
and many of the mines operate at marginal profitability. Nevertheless, gold continues to
be produced from 38 mines within the province. Silver from 37, Platinum Group Metals
from 10, uranium oxide from 7 and pyrite (for sulphur) from 5 of these mines.
Important in contributing towards gold production in Gauteng today is the reworking and
extraction of economic minerals from the slimes dams and mine sand dumps which are
spread over large areas of Gauteng. For example, the East Rand Gold and Uranium
Company Limited (ERGO) is at present involved in the extraction of low concentrations of
gold, silver, uranium oxide and pyrite (for sulphur) from slimes dams and mine dumps
all over the East Rand Goldfield. The chances of finding any more major gold deposits in
Gauteng is rather slim and future contributions are most likely to come from:
a.
the reworking of existing slimes dams and mine dumps occuring all over the
Witwatersrand,
b.
the re-engineering and re-structuring of large, marginal mines into smaller, much
leaner operations,
c.
the scavenging of abandoned stopes where the pillar structures are mined, the
stopes sweeped and vacuum cleaned, and even the wood structures recovered
from the stopes are burned and any gold trapped in it recovered,
3
d.
‘as in the case of the proposed Argonaut project, to extend workings further down
dip’.
3. DIAMONDS
Gauteng is blessed with one large operating kimberlite-diamond mine, the Premier Mine
north-east of Pretoria, which produces an unusually high proportion of large gems.
4. DOLOMITE AND LIMESTONE
Dolomite and limestone are mined in Gauteng from carbonate rocks belonging to the
Malmani Subgroup of the Transvaal Supergroup. Both are important industrial
commodities and they have numerous applications in industry. There are at present 4
dolomite and limestone mines in Gauteng of which two belong to Kumba Resources
(Iscor) and one to Samancor.
5. SILICA
Silica of metallurgical grade is being mined at two localities in Gauteng from
Magaliesberg quartzites, the companies involved being Iscor and Ecca Minerals.
6. REFRACTORY CLAYS
Refractory clays are extensively used in industry and are mined at a number of localities
in Gauteng, with operations belonging to Vereeniging Refractories, Iscor Refractories,
Ecca Minerals, Ndebele Mining Co., Ecca Minerals and Leolorde Mining Co. These clays
are closely associated with shales of the Vryheid Formation of the Karoo Supergroup and
occur mostly in north and east Gauteng. The Council for Geoscience is at present
investigating these resources with a view to establishing more accurate figures on the
volumes and qualities of refractory clays in Gauteng, in an effort to optimise the
utilisation and to prevent the sterilization of this valuable resource by urbanisation.
7. BRICK-MAKING CLAYS
Brick-making clay resources in Gauteng should become increasingly important as the
Rural Development Programme (RDP) housing projects escalate. The most important
brick-making clay resources in Gauteng have been documented by the Council for
Geoscience (CGS) and their geographical localities as well as their relation to existing
development and infrastructure are indicated on a clay distribution map which can be
optained from the CGS’s publications shop. The map will be useful in town planning to
ensure that this vital commodity is not sterilised. At present there are some 40 brickclay
producers in the Gauteng province.
8. AGGREGATE AND SAND
These commodities are also becoming increasingly sought after and important for future
development. According to statistics there are 55 operating quarries in the province.
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9. UNEXPLORED RESOURCES
It is believed that gold will remain the main contributer to Gauteng's income for some
time to come. It is unlikely that any more big gold deposits will be found in this province
as exploration has been conducted extensively in the past. ‘However, remnants of known
reefs and portions that have been faulted may well be extracted as is proposed at the
new Skukuza project in the East-Rand’.
5
A SUMMARISED MINERAL PROFILE OF THE NORTH-WEST PROVINCE
by MC du Toit, Council for Geoscience.
1. INTRODUCTION
This summary is subdivided into three categories of mining activity viz. the larger mining
operations as found in the platinum and gold mining industries, followed by some
remarks under the heading Smaller producing mines, which in no way diminishes their
importance to the Province. Finally the category other includes some commodities with
potential for increased production.
2. LARGER PRODUCING MINES
‘Nine of the 14' producing Platinum group metal mines in South Africa are situated in the
western limb of the Bushveld Complex in the northeastern part of the Province. These
mines have, for several decades, yielded the bulk of the total platinum group metal
output from the world famous Merensky Reef and UG2 chromitite layer of the Bushveld
Complex, though the eastern limb and platreef are growing rapidly in importance.
Substantial earnings also come from copper and nickel by products.
The Klerksdorp goldfield, constituting seven producing mines, is part of the larger
Witwatersrand goldfield. It is an important contributor to the South African gold,
uranium and pyrite (sulphur) production. These mines still have a substantial reserve
base of gold-bearing reef which, at the current rate of exploitation, is likely to last for
many years to come.
Chromite production takes place in the lower portion of the Bushveld Complex in the
Rustenburg area and immediately west of Pilanesberg in an area known as the Mankwe
area.
3. SMALLER PRODUCING MINES AND QUARRIES
Although the mines described under this heading are all appreciably smaller in
production output, capital outlay and so forth, their contribution to the welfare of the
region must not be considered as of lesser importance. While some of them, such as the
chrome mines, have the ability to expand into slightly bigger concerns, others may
remain operating at a relatively smaller scale for many years to come, supplying
important products for local consumption and\or export. However, these mines are all
labour intensive while profit margins vary from one commodity to the next.
3.1. The Bushveld Complex
The RSA's production of chromium comes from the mineral chromite, produced from
some 12 mines sited on chromitite seams south and west of the platiniferous Merensky
Reef of the western Bushveld Complex in the Rustenburg area and west of Pilanesberg
(Mankwe area). About one half of South Arica's chromite production comes from the
Province. Ferrochrome is produced by 4 plants, two of which are located in Rustenburg
and two elsewhere in the district.
Vanadium pentoxide is produced from magnetitite layers well north of the Merensky Reef
in the area northeast and northwest of the town of Brits.
6
There are more than 20 operations which quarry gabbro-norite of the Bushveld Complex,
in the area northeast of Rustenburg, producing what is known in the trade as black
granite which is used extensively as cladding material for prestigious buildings and for
tombstones.
3.2. The Transvaal Supergroup
The production of zinc and lead concentrates from the Pering Mine southwest of
Vryburg, will come to an end in 2002, because the orebody has been mined out. The
hostrock is dolomite of the Transvaal Supergroup.
Acid and metallurgical grade fluorspar is currently produced from two mines hosted in
dolomites in the vicinity of Zeerust and Marico, while limestone and dolomite are
produced from two quarries in the Lichtenburg District and two in the Zeerust District.
Manganese dioxide is exploited as surficial manganiferous earth accumulations on
dolomite in the Lichtenburg district.
Iron ore (specularite) is produced on a small scale from ferruginous shales of the
Pretoria Group some 40 km northwest of Rustenburg while refractory andalusite is
exploited from only one quarry in the Marico District.
Blue asbestos (crocidolite) exploitation, from operations located at Pomfret on the
northern border of the Province was terminated in 1998.
Quarrying of slate (for floor tiles) takes place from 9 active operations in the districts of
Swartruggens, Marico and Koster, while wonderstone (dimension stone) is being
exploited near Ottosdal. Andalusite is produced from the weathered shales in the vicinity
of Marico while talc and pyrophyllite are quarried in the Lichtenburg district.
Limestone is quarried at several sites for the use in both the cement industry and for
agricultural purposes while shale is mined for cement manufacture. As far as could be
acertained, clay is mostly mined for use in the brickmaking industry near every larger
growth centre in several districts.
Pure silica sand is produced from the slopes of the Magaliesberg in the Brits and
Rustenburg Districts and used in the process of glass manufacture.
3.3. Other
Diamonds are mined from kimberlite fissures north of Swartruggens and from alluvial
materials in the Lichtenburg-Ventersdorp and Schwizer Reneke areas, as well as along
the Vaal river. ‘There has been a signifisant increase in the number of alluvial diamond
operations recently and potential still exists’.
‘Gold is being successfully exploited at the Kalgold (Goldridge prospect) operation north
of Kraaipan and is intermittently produced near Amalia. Gold exploration in the Kraaipan
area has also led to the discovery of low grade platinum mineralisation in the area’.
Saltworks are found in the Vryburg and Delareyville Districts as well as along the Vaal
river.
The construction industry is supplied with aggregate derived from norite waste at
dimension stone quarries as well as quartzite obtained from the Magalieberg Formation,
while building sand is also derived by weatering of the latter formation.
7
A SUMMARISED MINERAL PROFILE OF MPUMALANGA
by J H W Ward, Council for Geoscience
1. INTRODUCTION
According to Minerals Bureau statistics, mineral production sales for Mpumalanga
Province during 1994 totalled R 9 280 million (‘in 2000 R 19 295 million’) of which
precious metals accounted for R 1 305 million, base metals amounted to R 143 million,
and coal accounted for
R 7 644 million. Sales of industrial minerals and miscellaneous production amounted to
R 189 million.
2. PRECIOUS METALS
Extensions to the Witwatersrand basin underlie the southwest portion of Mpumalanga.
These include the dormant South Rand goldfield and the producing Evander goldfield.
From 1958 to date, the latter has yielded over 1000 t of gold from four mines - Bracken,
Leslie, Kinross and Winkelhaak. The increased tempo of exploration for gold in South
Africa during the 1980s will have included a re-assessment of the South Rand and
Evander goldfields, but no significant discovery leading to the potential development of
new gold mining projects in these goldfields has been announced by the mining houses
involved. Mineral rights in the area with any potential for gold of economic interest will
be securely held by the mining companies which have vested interests in these
goldfields.
The search for small additional reserves of gold in Mpumalanga Province will include a
re-examination of deposits in the Transvaal Drakensberg and Barberton goldfields. In
the former case, Transvaal Gold Mining Estates (Randgold) hold the mineral rights for
the majority of the significant former gold producers in the goldfield, and have recently
sold 51% of the holdings to an Australian mining house, Beachcove. In the case of the
Barberton goldfield, the mineral rights to significant former, present or potential gold
producers are mainly held by South African mining houses. In addition to the mineral
rights being tightly controlled, the oxidised or non-refractory gold ore has long since
been exploited. What may remain in some former gold workings is refractory ore that,
following some form of tribute agreement with the mineral rights holder, could be mined,
milled and concentrated for sale, at a modest profit, to a beneficiation plant capable of
extracting gold from refractory concentrates.
‘Intensive exploration of the Critical zone of the Bushveld Complex is underway on the
eastern limbs of the Complex lying within Mpumalanga. Within the next few years
significant Platinum Group Metals (PGM) mines will be operating within the province,
exploiting the UG2 in most cases. There is significant potential for further exploration,
particularly in the area south of Groblersdal’.
Platinum group metals have been
produced as a by-product from the Nkomati nickel mine since 1997.
3. BASE METALS
Mpumalanga Province includes important ferrochrome, ferromanganese, ferrosilicon, and
ferrovanadium production facilities. Some of the feedstock for these metallurgical plants
is mined from silica, chromite and vanadiferous magnetite deposits in the Steelpoort
area. The scope for down-scaling these operations to the level of small mining is
8
minimal, and the development of small to medium business enterprises might be better
focused on the provision of services to the ferroalloy producers in the area. The
commissioning of the comparatively low-grade Nkomati PGE-nickel mine west of
Barberton has been a boost to base metal production in the province.
A small deposit of argentiferous zinc at Bien Venue in the Barberton greenstone belt
could be amenable to exploitation on a scale similar to that of the Maranda zinc mine in
the Murchison schist belt. In the past, very small operations were established on minor
antimony, cobalt, copper, iron, manganese and tin occurrences in the province.
4. COAL
All or part of the Witbank, Highveld, Eastern Transvaal, South Rand and KaNgwane
coalfields are included in Mpumalanga Province. A number of significant coal seams
possessing diverse characteristics are present and have a variety of potential markets in
the power generation, export, domestic, metallurgical, liquefaction and chemical sectors.
This is the most important coal-producing area in South Africa and supports some 65
collieries working several seams in the Ecca coal measures. The Witbank coalfield
contains a large and very important resource of high yield export quality steam coal,
especially in the No. 4 seam. In the adjacent Highveld coalfield the equivalent or No. 2
seam contains low-grade bituminous coal which is better suited to synfuel and power
production. As a rule, close to surface the coal seams are highly weathered to dross and
are not amenable to coal recovery from small-scale surface pig-rooting. In some cases,
accidents of topography may permit the recovery of limited quantities of coal from lowcost adit mining, but generally the scope for small-scale operations is restricted to the
value that may be recovered from the hand sorting of waste tips at operating collieries.
About eight farms in the Ermelo district are underlain by substantial resources of peat,
which could have potential value for the horticultural industry.
5. INDUSTRIAL MINERALS
The following industrial minerals are being, or, in recent years, have been produced from
mining operations in Mpumalanga: andalusite, chrysotile asbestos, clay, kieselguhr,
limestone, magnesite, talc, shale, silica, sand, stone aggregate, dimension stone and
ornamental stone. Commercial and industrial demand for these commodities stems from
a variety of applications in the following general categories: abrasives, ceramics,
chemicals, construction, fertilizers, glass, insulation, paint paper, plastics, refractories
and synthetic fibres. In the industrial minerals field, and in addition to the normal
provision of sand and aggregate to the construction industry, the province is particularly
known for the production of chrysotile asbestos, magnesite, verdite and the popular
dimension stone known as black granite. At the smallest scale of production there may
always be scope for potential entrepreneurs in the industrial minerals field to form
alliances with existing producers and to supply raw material from nearby small surface
pitting operations, provided that the mineral rights can be accessed. By the sporadic
nature of such potential operations, maintenance of safety standards and proper
rehabilitation of the workings would be problematical.
9
A SUMMARISED MINERAL PROFILE OF THE FREE STATE
By CJ Vorster, Council for Geoscience
1. INTRODUCTION
A total of 9 commodities are currently being exploited in the Free State, of which gold
and its by-products (uranium, silver, platinum group metals and sulphuric acid) are by
far the most important, followed by diamonds and coal. Ferrous and base metals are not
exploited at all, while industrial minerals, play an important role. Revenue from the Free
State Province's mineral products are the fourth highest within South Africa (after
Gauteng-, North-West- and Mpumalanga's Province), with total sales for 1994 being
valued at R 7 418 million (‘in 2000 R 7 037 million’).
2. GEOLOGY
Most of the Free State Province is underlain by sedimentary rocks belonging to the
Beaufort and Ecca Groups of the Karoo Supergroup. These constitute sandstone, shale
and mudstone, whitch have been intruded by dolerite sills and dykes. These rocks are
part of the vast Karoo basin, that covers almost two-thirds of South Africa, and were
deposited between 200 and 300 million years ago. Thy are known to host major coal and
clay deposits. The former generally occur as fairly thick, flat, shallow-lying coal seams.
Of the country's 18 principal coalfields, two occur in the Free State Province, these being
the Vereeniging-Sasolburg and Free State fields.
In the northwest of the Province the Karoo Sequence overlies rocks of the Witwatersrand
and Ventersdorp Supergroups. In the vicinity of Vredefort and Parys, the well-known
Vredefort Dome crops out, revealing Witwatersrand sequence rocks on surface.
The most important occurrences of gold, both in the Province and South Africa, are
found in conglomerates of the upper division of the Witwatersrand Supergroup and the
basal formation of the overlying Ventersdorp Supergroup. The gold is preserved in fan
and delta deposits where it was deposited by fluvial systems. This great basin stretched
over 300 kilometres from the Welkom area to the Klerksdorp area, and from there
eastwards to the present Springs-Nigel region, east of Johannesburg. The Witwatersrand
was deposited over a time span of some 250 million years, commencing about 3 000
million years ago and is up to 7 500 metres thick.
South Africa's gold production dropped from 672,9 tonnes in 1985 to 579,9 in 1994
(‘and 428,2 tonnes in 2000').
There are currently seven gold fields exploited in the Witwatersrand Basin of which the
Free State gold field is the second most important, having produced 157,37 tonnes in
1994 (‘98,6 tonnes in 2000') valued at R 6,768 billion. Total sales of silver amounted to
45 021 kg (R 5 937 570).
3. LARGER PRODUCING MINES
3.1 Gold
The Free State gold field falls entirely within the Free State Province. Many big mines,
some of them also producing uranium, are active here. Though a substantial quantity of
gold remains in the field, the generally lower grades and weak gold prices, combined
10
with increasing production costs in real terms, as the deposits are mined at ever-deeper
levels, means that some of the gold mines have become marginal to sub-economic and
face closure in the near future.
A total of 16 gold mines are still active in the Free State goldfield, namely the
Beatrix,Matjhabeng, Free State Saaiplaas, HJ Joel, Harmony, Loraine, Oryx, President
Steyn, ARM, Tshepong, Masimong, Target, Jeanette, President Steyn, St Helena and
Unisel mines. Although exploration confirmed gold reefs in the area between Bothaville
and Odendaalsrus, development has been delayed because of structural problems and
low gold values.
3.2 Coal
The Vereeniging-Sasolburg coalfield ranks third in South Africa in order of importance,
while the Free State supplied a saleable output of 10,5 per cent of the national coal
output. Two mines are producing, namely the New Vaal Colliery and Sigma Mine, both
exploiting bituminous coal. Sixteen years ago some 5 000 Mt of low grade coal, suitable
for power generation and the possible production of liquid fuel, was proven by
exploration.
Total coal (bituminous) produced during 1994 amounted to 18 717 604 Mt with total
sales of 18 987 621 Mt valued at R 556 079 120.
3.3 Diamonds
Diamond production has been important in the Free State Province for decades. The well
known Jagersfontein, and Monastery mines have been closed, but 4 mines are currently
producing diamonds from Kimberlite rock, namely the Samada, Koffiefontein, Salene
(Star) and Sonnenberg (Loxton).
Total diamond production during 1994 amounted to 198 564 carats with total sales 101
727 carats valued at R 31 155 986.
4. SMALLER PRODUCING MINES
4.1 Clay
Bentonite occurs in the Koppies District of the Free State. The deposits are flat-lying and
lenticular, occupying embayments in pre-Karoo metasediments and are overlain by Ecca
shales. The clay consists of a very pure montmorillonite with only small amounts of
quartz, and is probably formed through the in situ weathering of volcanic ash.
Well known here is the Oceaan deposit in the Koppies District, which, in 1980 produced
80 per cent of South Africa's production. At that stage reserves were more than 700 000
t and were sufficient for two decades at these production levels.
4.2 Limestone
Calcrete is present in the western parts of the Free State Province and limestone
reserves are substantial. Agricultural- and dolomitic limestone is being produced in
opencast workings in the Henneman and Viljoenskroon Districts.
4.3 Salt
Salt is produced from salt pans in the Western Free State where it has been precipitated
11
by the evaporation of brines. Production is concentrated around the Florisbad salt pan,
north-northwest of Bloemfontein. Salt is being produced from some 20 localities.
During 1994 a total of 31 433 mt salt was produced and 32 822 t sold valued at
R3 990 672.
4.4 Gypsum
Gypsum is produced from an opencast working in the Boshof district.
4.5 Granite
Rough granite blocks are extracted in the Parys district for use as dimension stone.
4.6 Sand and Stone Aggregate
Sand and stone aggregate are produced from various quarries in the Province. A
quantity of 3 622 065 t aggregate and sand was sold during 1994, with a value of R 41
997 109.
5. COMMODITIES WITH POTENTIAL FOR FUTURE MINING
Titanium, zircon, rare earths and thorium are known to occur in fossil beach sands north
of Bothaville. Reserves were estimated at 82 Mt ore, including 18,3 Mt ilmenite and 1,9
Mt zircon. Development is hindered by high recovery costs and the fact that the deposit
lies in high-potential agricultural soil.
Uranium mineralisation occurs in the Beaufort Group in the south western part of the
Province, and also in the Elliot Formation near Ficksburg. The deposit on Mooifontein,
near Edenburg, is the only occurrence with possible economic potential.
12
A SUMMARISED MINERAL PROFILE OF LIMPOPO (NORTHERN PROVINCE)
By M.G.C. Wilson, Council for Geoscience
1. INTRODUCTION
South Africa is a land blessed with a staggering array of mineral resources, this variety
reflecting its long and diverse geological history that goes back 3,7 billion years.
Limpopo is well endowed with a wide variety of minerals, some of the more important of
which are mentioned below. The Minerals Bureau has records of just over 70 operating
mines in the province, 50 of which are small to medium scale mines. The larger mining
operations in the province include the Venetia diamond mine, the Grootegeluk and
Tshikondeni collieries, the Amandelbult, Northam, Potgietersrust, Messina, Lebowa,
Marula and Modikwa platinum mines and the copper and phosphate operations at
Phalaborwa. Between them, these deposits accounted for some 80% of the provinces
mineral revenue. The province's primary minerals income made up 10.3% of South
Africa’s total primary mineral sales in 2001. Within Limpopo, the mining sector paid in
excess of R 2.5 bn in remuneration in 2001.
2. LARGER MINES
Dark, basic rocks of the Bushveld Complex sub-outcrop in an arcuate zone within the
province, from Steelpoort in the east, through Grasvally, south of Mokopane
(Potgietersrus), to Swartklip in the west. There is an appendage of Bushveld rocks,
which runs northward from Grasvally, through Mokopane, almost to the Blouberg
mountains. The platinum group element (PGE), nickel, copper and cobalt bearing
Platreef, which occurs in this northern limb, is presently exploited on the farm Sandsloot,
by Potgietersrust Platinums. The famous platinum and chromium bearing, Merensky Reef
and chromite bearing horizons such as the UG2 (significant host of PGE's) and LG6,
occur within these mafic rocks and are mined at the Modikwa, Marula, Lebowa, Messina,
Northam and Amandelbult platinum mines and at the Dilokong and Montrose chromite
mines. Intensive exploration for PGE’s is underway on both the Eastern and the northern
Platreef Limbs of the Bushveld Complex, whilst the Twickenham platinum mine, as well
as a large PGE smelter are currently being constructed.The Phalaborwa Complex, which
is one of the world's great mineral repositories, contains large deposits of copper,
magnetite (iron ore) and apatite (phosphates), as well as the world's largest deposit of
vermiculite (an expanding mica used in horticulture, agriculture and construction). It
also hosts important concentrations of zirconium (in the form of baddeleyite),
uranothorianite, nickel and precious metals. These deposits are successfully mined by
the Palabora Mining Company and Foskor.High-grade hematite is mined from the Penge
Formation at Kumba Resources' Thabazimbi Iron Ore Mine in the southwest of the
province, for shipment to the Vanderbijlpark and Newcastle steelworks. Vanadiferous
and titaniferous magnetites are being mined in the east of the province at Mapoch’s and
Magneethoogte.
The Karoo sediments include carbonaceous shales and coal. The coal deposits have been
preserved in four downfaulted basins in the Limpopo Province, known as the Waterberg,
in the vicinity of Lephalale (Ellisras), Soutpansberg (along the northern flank of the
Soutpansberg mountains), Limpopo (along the southern bank of the Limpopo river, west
of Musina) and Springbok Flats coalfields. These coalfields contain large reserves of coal,
with the Waterberg coalfield reckoned to hold more than 40% of South Africa's in situ
mineable coal reserves. These vast resources are presently being mined at the large
Grootegeluk coal mine. The small Tshikondeni mine is the only currently operating coal
13
mine in the smaller Soutpansberg coalfield and yields high-grade coking coal for Iscor's
steel mills.
The Murchison greenstone belt has yielded some 20% of the world's antimony and
almost 30 t of gold, from the Consolidated Murchison Mines, as well as significant
amounts of zinc and copper (the Maranda and Ramotshidi mines currently operating),
mercury, gold (from non-antimonial deposits), paving and cladding stones (La Mei) and
emeralds.
The intrusive Venetia kimberlite, west of Musina is currently South Africa's largest
diamond producer and contributes the largest portion of the Limpopo province's mineral
revenue.
3. SMALLER MINES
The Pietersburg greenstone belt contains the Eersteling, Mt. Maré, Mt. Robert and
Roodepoort goldfields, with the first two having been exploited until recently at the
Eersteling and Zandrivier mines. The Witkop silica deposit, just south of Polokwane, is a
greenstone hosted quartz vein, mined by Silicon Smelters and used to produce silicon
metal. As this deposit is almost exhausted, other silica deposits are increasingly used to
supply raw material for this plant. Two significant silica deposits are known in the east of
the province, near Gravelotte and Phalaborwa.
The smaller Giyani (Sutherland) greenstone belt, in the east of the province, has yielded
at least 10 t of gold from numerous small and six larger deposits (all closed at present),
namely the Klein Letaba, Franke, Birthday, Fumani, Golden Osprey and Louis Moore
mines. Large magnesite deposits were exploited here in the past. It is believed there is
further potential for gold in this belt.
The sediments of the Pretoria Group which, though not widely mineralised, do host large
andalusite deposits, the Havercroft, Annesley and Hoogenoeg deposits, south east of
Chuniespoort, being three of these, whilst the Rhino deposit, near Thabazimbi in the
west of the province, is the largest producer in the country. Southwest of Rhino is the
new Maroelafontein andalusite mine.
The small Oaks diamond mine, in the west of the province, is operated by De Beers and
the Klipspringer kimberlite fissure mine, east of Mokopane, is operated by Southern Era.
In 1993, regional heavy mineral sampling to the east of Klipspringer revealed a potential
diamond anomally. During the next four years follow-up work established a small
mineable reserve at Marsfontein and the kimberlitic blow was mined from August 1998
until the end of 2000. This deposit, though small, repaid all capital outlay with its first
3.4 days of production and turned out to be one of the richest kimberlites ever exploited
with the 970 347 t extracted having yielded 1.826 Mct valued at US$ 246.3 million. It is
believed that potential exists for further diamond exploitation within the province and
active diamond exploration is being conducted in several areas.
Near Dwaalboom in the southwest of the province, a large calcrete deposit is being
exploited for use in cement manufacture. There are other similar calcrete deposits in the
area.
The granite pegmatites south of the Murchison Range, in the Mica area, have yielded
abundant silica, feldspar and mica in the past and the Pegmin, Freddies and Gelletich
operations still produce.
14
The quartz and feldspar rich granitic rocks associated with the Bushveld Complex are
being exploited as dimension stone, west of the Potgietersrust Platinum mine, at the
Ketter, Lebowa Granite and Destaf quarries.
More recent surficial deposits include important resources of sand (12 deposits) and clay
(nine deposits) which are used largely for the making of bricks and in local construction.
4. AREAS WITH POTENTIAL FOR MINING
Providing there is continued demand for both platinum group metals and chromite and
the price of these commodities remains good, other platinum and chromite deposits are
likely to be mined in the future, from rocks of the Bushveld Complex. As mentioned
above, active exploration is in progress for PGE’s, particularly north and south of
Mokopane. The basic intrusive rocks of the Bushveld Complex also have the potential to
be quarried as dimension and monumental stone, where they outcrop and are joint free.
The potential also exists, particularly in the east of the province, for the exploitation of
titaniferous and vanadiferous magnetites.
There is a strong likelihood that more coal will be mined from the province's coalfields in
future, though high transportation costs have prevented their export to date. In the
deeper parts of these coal basins, there is a potential for extracting coal-bed methane
gas, as an energy source.
Just to the north of Polokwane (Pietersburg), the Zandrivierspoort greenstone outlier
contains a large, low-grade, iron ore deposit. Another deposit of titaniferous iron ore
occurs in the Rooiwater Complex, adjacent to the Murchison greenstone belt. The alluvial
deposits emanating from this have been evaluated by Kumba Resources (Iscor) and
there is a chance that they may be exploited.
Gold is also known in the metamorphosed greenstone remnants of the Bandelierkop
Formation (the Venda and Overschot gold deposits, north of Soekmekaar, being
examples), as well as within gneisses at deposits such as the defunct Harlequin and
Bochum mines. Some of these deposits hold promise for small scale mining ventures. In
the extreme southwest of the province gold is known in what were called the Batavia
goldfields as well as at the Mazuma and new Dwaalboom deposits.
Ancient rocks of the Beit Bridge Complex, in the north of the province, are known to host
flake graphite, ironstone and marble, as well as the much younger Messina copper
deposits, which though dormant, may yet offer scope for further development.
Great thicknesses of dolomite and limestone, exploited in places, represent a good
potential source of aggregate and lime, as well as hosting small manganese and lead
deposits in places.
The now closed tin mines at Rooiberg, Leeuwpoort, Union tin, and Grassvally, may yet
offer further potential in the future. The slimes dams at Zaaiplaats are currently being
reworked for their economic mineral potential as are the dumps at the defunct Buffalo
fluorspar mine, which was once the largest fluorspar producer in the world.
Fire clay, surficial limestone and magnesite deposits are also known in several localities
including the Springbok Flats and Soutpansberg and are exploited from time to time.
Lead, barite and copper mineralisation is known within the sediments that form the
Blouberg and Soutpansberg mountains and the potential exists for as yet undiscovered
deposits of these metals.
15
16
A SUMMARISED MINERAL PROFILE OF THE NORTHERN CAPE PROVINCE
By M.C. du Toit, Council for Geoscience.
1. INTRODUCTION
The Northern Cape Province is the largest of the 9 Provinces, with most of the mineral
deposits concentrated along its northern sector, which has been stripped of its Karoo
cover. As the climate tends to be arid, the availability of water becomes a major factor in
the establishment of mining ventures at any scale. However, the Orange River traverse
part of the mineral-rich area, whilst the infrastructure has been steadily developed since
the 1950's, when the Sishen Iron Ore Mine came into production, and was further
stimulated in the early 1970's, by the discovery of substantial base metal orebodies and
the construction of the Sishen-Saldanha rail link. The mineral potential of the Province is
briefly discussed under three headings viz. that of Larger producing mines, Smaller
producing mines and quarries and lastly, deposits with mining potential.
2. LARGER PRODUCING MINES
The Sishen Iron Ore Mine in the Postmasburg district produces 22 Mt of iron ore annually
of which 67% is exported, while the rest is consumed within South Africa. The Kalahari
manganese field is located some 65 km further to the north. Manganese ore is produced
from 5 operating mines. The entire manganese field is overlain by a sand cover, known
as the Kalahari Formation.
Lead-zinc-copper-silver ore is exploited at Aggeneys in Namaqualand, some 100 km
north-northeast of Springbok. Of the 4 orebodies, only one is presently being mined,
whilst a second is being prepared for future mining. The ore is concentrated on site as
copper, lead and zinc concentrates and transported first by road to the Sishen-Saldanha
rail, then by rail to Saldanha from where the concentrates are either exported or
distributed to local refineries.
Kimberlite-hosted diamonds have been produced from the cluster of diamond mines
around Kimberley, which once were the backbone of the South African diamond industry.
Current production still comes from the Finsch Mine some 40 km east of Postmasburg as
well as from the Dutoitspan and Wesselton Mines at Kimberley. Alluvial diamonds are
worked, mostly on a small scale, from ancient river-borne gravels intermittently
preserved from the Barkly West diamondfields (adjacent the Vaal River near Kimberley),
westwards through Bitterputs in Namaqualand to the lower Orange River, andnear the
West coast. Marine diamonds are exploited at irregular intervals along the West coast at
Koingnaas, Kleinzee and Alexander Bay, the latter being the oldest operation.
3. SMALLER PRODUCING MINES AND QUARRIES
Iron ore and mineral pigments, are mined on a smaller scale at the Beeshoek Mine west
of Postmasburg and at Rooinekke further to the south, while exploitation of the adjacent
Postmasburg manganese field was discontinued in favour of the larger Kalahari field.
Copper ore is mined at Nigramoep and concentrated and refined at Nababeep, some 14
km northwest of Springbok in Namaqualand. This mineralisation has been known since
1685, but regular exploitation started in 1852 and has continued till the present.
Limestone for the cement industry is mined at Ulco, Postmasburg and Barklay West,
17
while gypsum, also used for the cement industry, is mined at Warrenton. Gypsum is also
extracted from deposits at Grootlemoenkop in the Calvinia District as well as in the
Districts of Namaqualand and Prieska.
Limited quantities of Silicified asbestos, known as tiger's eye, is obtained from near
surface occurrences in the Niekerkshoop-Griquatown area and sold as a very popular
semiprecious stone.
Both sillimanite and wollastonite are exploited from small open workings in Namaqualand
whilst barite is produced from Gamsberg near Aggeneys.
Although the Namaqualand-Kenhardt pegmatite belt is very extensive and contains
thousands of pegmatite bodies, only a few have been exploited successfully in the past.
Attempts to mine several other pegmatites on a small scale have failed due either to a
lack of water or infrastructure as well as the limited size of the pegmatites. The odd
Kenhardt pegmatite is being exploited mainly for its feldspar which is used in the
ceramics industry, whilst the pegmatites in the vicinity of Blesberg in Namaqualand,
yield small quantities of tantalite, bismuth, mica and feldspar.
Salt is beneficiated from some 24 saltpans scattered over a large part of the Province;
there are 2 salt workings in the Britstown area, 2 near Calvinia, 3 near Herbert, 4 near
the Hopetown, 1 in the Jacobsdal, 1 in the Kimberley, 9 in the Gordonia, 1 in the
Douglas and 1 in the Vryburg Districts.
Granite and charnockite are extracted as dimension stone at Springbok and Garies in
Namaqualand. The Springbok operations require road transport to the nearest railhead
at Bitterfontein. Some marginal operations, such as that extracting the Lekkersing
quartzite in the Richtersveld, closed down due to a total lack in infrastructure and weak
demand.
Ceramic clay is produced in the Calvinia and Hopetown Districts, while kieselguhr, used
principally as a filtering agent, is exploited from pans in the Hay District.
4. DEPOSITS WITH MINING POTENTIAL
The Gamsberg zinc deposit near Aggeneys and the Black Mountain deposit at Aggeneys
have yet to be mined. At present the price of zinc metal is too low to allow for profitable
extraction from these deposits. The three small copper orebodies at Putsberg have no
potential for a larger operator, nevertheless, with the appropriate feasibility study, they
may sustain a small operator.
Although the Prieska Mine at Copperton has closed down and the Areachap orebody is
too small to be mined, the rocks of the Areachap Group constitute a sulphide-rich
province, the true potential of which has yet to be fully evaluated.
The pegmatite belt presents the small operator with many challenges and problems, but
for the dedicated and hard working operator, there may be some opportunity for
extracting feldspar, mica and rose quartz, in the Kenhardt and Namaqualand Districts.
18
A SUMMARISED MINERAL PROFILE OF KWAZULU/NATAL
by H.G.Hira, Council for Geoscience
1. GEOLOGY
The oldest rocks in Kwazulu/Natal can be subdivided into two major groups. In the
northern part of the province outcrops form part of the Archaean Kaapvaal Craton, which
was formed more than 2 500 million years ago and hosts numerous minor gold
occurrences. In the south, the oldest rocks forming the basement are about  1000
million years old and their poorly exposed outcrops cover some 10 000 km 2 of
Kwazulu/Natal. These rocks have been subdivided into three distinct Terranes based on
geological characteristics. It is noted that there is a decrease in the abundance of
mineral deposits from the Tugela Terrane in the north, to the central and southern
Mzumbe and Margate Terranes.
In the Tugela Valley, the rocks of the Tugela Terrane are in tectonic contact with the
Archaean rocks. Due to the rugged topography and inaccessible nature of the remote
parts of this northern Terrane, there has been systematic exploration for new deposits in
this area but there is potential for finding new orebodies. The basement is overlain by
the Ordovician-Silurian aged sandstones of the Natal Group in the east, as well as by the
younger Carboniferous to Jurassic sediments and volcanics of the Karoo Supergroup,
which host much of the industrial mineral deposits. Surficial sediments of various ages
form the most recent cover.
2. MINERALS CURRENTLY BEING EXPLOITED
2.1 Heavy Mineral Sands
Ilmenite, rutile and zircon are being mined on a large scale for their titanium and
zirconium contents, from aeolian beach dunes on the north coast of the Province. Large
ore-reserves are held by Richards Bay Minerals. A smaller deposit is currently exploited
by Ticor at Hillendale, east of Felixton. The ore is processed at Richards Bay, prior to
being exported. Heavy mineral sand deposits similar to those at Richards Bay also occur
south of Margate. Dune mining is a sensitive environmental issue and companies must
guarantee the rehabilitation of the areas prior to mining on these pristine coastlines.
2.2 Coal
In the northern interior part of the Province (Newcastle-Vryheid District) and in the
Nongoma area, the coal in the Karoo Supergroup (Vryheid Formation) consists mainly of
anthracite. Much of the anthracite is then washed and railed to the coal terminal at
Richards Bay, from where it is exported. Other types of coal from this area are utilised as
coking coal by Iscor. The pulp, paper and textile industries are the other major coal
users. A large amount of the reserves in the Province have been previously mined out.
At current rates of mining, most of the anthracite mines have potential reserves to last
another 15 to 20 years.
2.3 Marble
Calcitic marbles of the Marble Delta Formation in the Margate Terrane of the Natal
Metamorphic Province, 10 km northwest of Port Shepstone are mined in three large
quarries, which collectively are one of the most important producers of carbonates in
19
South Africa. High grade material from two of the quarries is used as a filler in high
quality paint and plastic, paper, toothpaste and bread, while the lower grade material is
used in the rubber, fibreglass, paint, agricultural and glass industries. Limestone from
the third quarry is used exclusively for cement manufacture. The carbonates produced
are largely for domestic use, with only  1% being exported, mainly to other African
countries.
At the present rate of mining, the three quarries have a life expectancy of over 100
years. Since the full extent of the Formation is unknown due to the complexity of the
geology, there is potential for locating new orebodies in this area.
2.4 Gold
The Klipwal gold mine was reopened in 1982 in the area known as the Pongola Goldfield
and is producing on a small scale. Other old mines in the area have been reinvestigated,
largely with negative results. A few of the old mines are now located in the Itala Game
Reserve.
2.5 Dimension Stone and Stone Aggregate
There are many granitoid rock types suitable for use as dimension stone in the Natal
Metamorphic Province, mainly from the Oribi Gorge Suite, which comprises ten large
bodies within the Mzumbe and Margate Terranes. Only one dimension stone quarry is
currently in operation in the Province. The Natal Granite Quarries, some 40 km NW of
Durban, extracts three hues of a coarse-grained, greenish-grey granite (charnockite),
the bulk of which is exported through Durban. The dimension stone industry is largely
market orientated and supply depends on fluctuating demand, mainly from overseas
markets.
Stone aggregate is produced from numerous small quarries throughout the Province and
is used locally for building material and road construction. The aggregates are produced
from Karoo Supergroup Dwyka tillite and dolerites, from sandstones of the Natal Group
and from various suitable granitic rocks, close to areas which require the material.
2.6 Brickclay/Shale
Karoo Supergroup clays derived from deeply weathered shale have, for many decades,
been exploited to produce bricks for the building industry and reserves are large. Shale
and slate from these areas have been informally mined by farmers as decorative
cladding stone.
2.7 Building sand
Coarse alluvial sand dredged from the many river mouths in the southern part of the
Province, is mixed with fine grained material from the Dwyka quarries to produce low
cost bricks for informal housing.
3. DEPOSITS WITH ECONOMIC POTENTIAL
3.1 Kaolin
Many deeply altered feldspar-rich granitic rocks of the basement, have considerable
potential as kaolin sources, with grades of up to 40% kaolinite recorded. Intermittent
small-scale mining operations have taken place in the past with only the purest, whitest
kaolin have being exploited. A kaolin processing plant was erected near Ndwedwe which
20
also produced high-quality silica as a valuable by-product, but political instability in the
area deterred potential investors.
3.2 Lithium
In the southern Terrane in the Port Shepstone District, significant quantities of
spodumene have been identified in a number of leucocratic pegmatoidal vein bodies.
Although further drilling is required to estimate the ore reserves, these pegmatites could
satisfy the lithium requirements of South Africa for a number of years. The pegmatite
also has potential to produce dimension stone and feldspar as useful by-products.
3.3 Mineral Fluxes
A possible source of nepheline-based mineral fluxes is situated in the northern margin of
the Tugela Terrane at Bulls Run. Pilot studies have indicated that, after beneficiation, the
composition of the nepheline syenite very closely approximates the specifications
required by the clear glass and whiteware ceramics industries.
3.4 Dolomite
Dolomites north of the Tugela River in the Ntshongweni District contain too much
magnesium for use in the lime and cement-making industries, however they are suitable
for use as agricultural lime. Reserves are estimated to be in excess of 100 million tons.
4. OCCURRENCES OF UNCERTAIN ECONOMIC POTENTIAL
4.1 Gold
While Kwazulu/Natal has never been a major gold producer, the province contains a host
of minor showings that have been mined on a small scale in the past. Since the early
part of the century some 400 kilograms of gold production has been recorded throughout
the province, mainly from the Archaean rocks and the Tugela Terrane. In the southern
part of the Mzumbe Terrane, the `Umzinto Goldfield' comprises about 16 gold
occurrences, prospects and old mines. An attempt was made to re-open the Dumisa
Mine in this area in early 1990.
4.2 Aluminium
Substantial resources of low-grade bauxite were identified in about 10 deposits and are
formed on weathered Karoo dolerites. Although these may not be a source of alumina,
they may be an important feedstock for a host of other aluminium-based industries. In
areas east of Kokstad and in the Vryheid District, reserves of 63 million tons of low grade
material have been proven, with sporadic occurrences throughout Natal. Unfortunately
many deposits are in environmentally sensitive locations. South Africa currently imports
its alumina requirements from Australia.
4.3 Chrome, Vanadium and Titanium
At Sithilo, south of Nkandla, high grade chrome concentrates were produced in the past.
However mineralisation is of limited extent and this has prevented viable exploitation.
Small, irregular chromite orebodies occur 10 km north of Kranskop but these are of low
grade.
Vanadium and titanium rich magnetite layers of unknown extent occur 20 km east of
Kranskop. The remote location and moderately low grades have reduced the economic
potential of the deposit.
21
4.4 Graphite
A graphite orebody with considerable reserves but very low grade, has been identified 8
km west of Southbroom on the south coast of the province, in the Margate Terrane.
4.5 Dimension Stone
In the southern part of the province there are many granitoids with considerable, but as
yet untested potential for use as dimension stone.
4.6 Talc
Five occurrences of talc have been investigated in the Tugela Valley between Kranskop
and Eshowe. However as the bodies were of irregular nature, reserves could not be
accurately estimated and the quality of the material was found to be marginal to poor.
22
A SUMMARISED MINERAL PROFILE OF THE WESTERN CAPE PROVINCE
By D.I. Cole, Council for Geoscience
1. INTRODUCTION
The predominant mineral resources in the Western Cape Province, as indicated on the
accompanying minerals map, are industrial, exploited by open cast mining, and in the
case of marine diamonds and heavy beach sands, by other appropriate methods. The
minerals profile is subdivided into three categories viz. Currently producing operations,
Presently unexploited deposits with potential and Resource areas.
2. CURRENTLY PRODUCING OPERATIONS
2.1 Limestone - Dolomite
‘Limestone is quarried for cement at De Hoek and Riebeek-Wes, for agricultural lime at
Vredendal, Saldanha, Bredasdorp and Rietgrove (Riversdal District), for feed lime at
Saldanha for limestone sand at Witsand, and for water treatment and chemicals at
Vredendal. Dolomite is exploited for agricultural purposes at Vredendal and Bridgetown,
for aggregate and refractories at Vredendal, for metallurgical flux at Bridgetown and for
building lime and chemicals at Langvlei (Robertson District). These commodities are
presently produced at 11 quarries’.
2.2 Clay minerals
In the Noordhoek Valley and Brackenfell-Somerset West region, good quality kaolin
deposits are present in weathered zones of the Cape Granite Suite. They are currently
exploited at Chaplin's Estate and are used in the ceramics and paper industries. The
Bottelfontein deposit, 35 km northeast of Cape Town, contains poor-quality kaolin in
weathered Klipheuwel Group sandstone and is quarried on a small scale for ceramics
manufacture.
Small isolated deposits of ball clay are present in palaeochannels excavated into bedrock
in the Kraaifontein and Albertinia areas. They are presently exploited for the ceramics
industry in the area south of Kraaifontein and east of Albertinia.
Bentonite is currently exploited at four quarries, three near Heidelberg and one east of
Knysna (Roode Fontein), mainly used in the oil refining and oil bleaching industry, as
drill muds in the deep drilling process, as pelletising agent for iron ore and as bonding
material for foundry moulds in the iron and steel industries.
Brick clay, for face and stock bricks, is produced from local clayey material near most
major towns in the Western Cape, since long-distance transport costs are prohibitive.
The best reserves have been delineated within 50 km of Cape Town, where they are
presently exploited at 17 sites.
Sedimentary plastic clay of Neogene age is present in small depressions and
palaeochannels between Stellenbosch and Atlantis and is exploited at six sites as a
plasticiser for brick-making by mixing with residual brickclay.
23
2.3 Dimension stone
Marble from the Widouw Formation occurs along a NW-trending zone centred on
Vanrhynsdorp, which merges with the limestone - dolomite field of the VredendalVanrhynsdorp area. It was exploited from several quarries since the 1920s, but the last
quarry, on the farm Widouw 309, closed in 1996. Isolated masses of charnockite, a dark
greenish-grey crystalline rock with indistinct porphyroblastic and granoblastic texture,
occur in the northern portion of the Vanrhynsdorp District and were quarried under the
name “Green Granite” near Bitterfontein and Kliprand. At Paarl, medium-grained granite
is being exploited for dimension stone at two quarries. On the farm Lambertshoek A 546,
southwest of Clanwilliam, sandstone of the Table Mountain Group is quarried for building
stone and dry stone walling, and on the farm Augsberg 197, outside Clanwilliam, thinbedded sandstone of the Bokkeveld Group is exploited for slasto.
2.4 Diamonds
Diamonds occur in marine placers on wave-cut platforms, along the coast in the
Vredendal District and continue northward into the Namaqualand District (Northern Cape
Province). They have been extensively exploited and are currently mined from the surf
zone at some 15 sites. Ancient diamondiferous marine placers, of lower grade, are also
present north of Vanrhynsdorp and are exploited at one site on the farm Bruintjes
Hoogte 40 in palaeogravel of the Swart Dorings River.
2.5 Heavy minerals
Heavy mineral-bearing beach and aeolian sands, containing the minerals ilmenite, rutile,
zircon and leucoxene, are currently exploited by Namaqua Sands, north of the Olifants
River. Ilmenite is being smelted into a titania slag, from which TiO 2 is produced for the
paint industry.
2.6 Glass and building sand
Glass sand is currently exploited on the Cape Flats near Philippi, at Consol's quarry. Sand
is also mined for foundry purposes on the farm Brakkefontyn 32, near Atlantis.
Building sand is found in the vicinity of most major towns in the Western Cape. In the
Greater Cape Town area, it is predominantly restricted to Aeolian dune sand near
Philippi and Macassar, and to hillwash sand south of Malmesbury. As a result of depletion
and urbanisation encroaching on deposits, a future shortage may occur.
2.7 Stone aggregate
Stone aggregate for the building industry is quarried close to its local market from any
suitable rock type, e.g. andesite north of Worcester and from hornfels adjacent to
plutons of the Cape Granite Suite. A total of 5 working quarries are exploiting the
hornfels in the Greater Cape Town area. Two working quarries near Saldanha and one
north of Malmesbury are exploiting granite of the Cape Granite Suite. Aggregate
quarries in sandstone of the Table Mountain Group occur at Caledon, Mossel Bay,
George, Knysna and Plettenberg Bay. Dolomite is quarried at Vredendal and limestone at
Robertson. Alluvial gravel from terraces of the Berg River is exploited at 4 sites south of
Paarl.
2.8 Mineral pigment and iron
Ferruginised shales of the Bokkeveld Group are mined as mineral pigment on Snymans
Kraal 358, 15 km northwest of Albertinia while a residual limonite (iron) deposit, grading
24
downwards into pyrite stringers, is currently being worked at Atties, northwest of
Vanrhynsdorp.
2.9 Gypsum and salt
Gypsum is currently being produced at Maskam, 5 km north of Vanrhynsdorp, and on
Yzerfontein Pan, while salt extraction is limited to sites north of Darlin, at Velddrif, and
on the farm Rietfontein Extension 151, 50 km northwest of Koekenaap. Many isolated
pans occur within 30 km of the coast and on the estuarine margins of the Berg and
Oliphants Rivers.
3. PRESENTLY UNEXPLOITED DEPOSITS WITH POTENTIAL
3.1 Rare earths and rare metals
The Steenkampskraal mine, 70 km north of Vanrhynsdorp, which in the past produced
rare earth elements and thorium from monazite concentrate extracted from a monaziteapatite-rich carbonatite breccia pipe vein, is to be re-opened shortly. The niobium and
thorium-bearing Salpeterkop in the Sutherland District is also under consideration, as
rare metals become more sought after with improved technology.
3.2 Tungsten-molybdenum
A substantial but subeconomic skarn deposit associated with a pluton of the Cape
Granite Suite is present in the subsurface at Riviera, 23 km north-northwest of
Piketberg.
3.3 Dimension stone
Substantial quantities of good quality limestone are present in the Cango Group, north of
Oudtshoorn but have not yet been exploited.
3.4 Phosphate
Numerous phosphate deposits occur in a 10 - 30 km wide zone within Neogene
sediments adjacent to the West Coast, from 35 km north of Cape Town to 40 km north
of Lambert's Bay. Calcium phosphate, the predominant ore, was formerly exploited for
fertilizer at Langebaanweg. Aluminium phosphate is present as vein-like deposits on
quartz porphyry of the Cape Granite Suite south and west of Saldanha and was
previously exploited. The larger phosphate deposits vary in size from 2,7 to 50 Mt of ore
grading at between 4 and 10 per cent P2O5. They are presently subeconomic, but one
mining company is prospecting two of the deposits. There are extensive low-grade, offshore deposits along the Cape coast.
4. RESOURCE AREAS
Isolated kaolin deposits occur in two areas northwest of Vredendal between Nuwerus and
the coast. Resources of good quality material were previously exploited for use in the
ceramics industry. North of Vredenburg, several small, good-quality, kaolin deposits are
present along fault zones in the Cape Granite Suite.
Limited resources in sub-economic, low-grade uranium-molybdenum deposits, occur in
sandstones of the Beaufort Group, northeast of Laingsburg, and continue into the
Northern and Eastern Cape Provinces.
25
Glass sand is present in the subsurface west of Hopefield, but further investigations are
needed in order to ascertain the potential of this deposit.
26
A SUMMARISED MINERAL PROFILE OF THE EASTERN CAPE PROVINCE
By A.G. Thamm, Council for Geoscience
1. INTRODUCTION
Unlike the mineral rich provinces in the rest of South Africa the Eastern Cape it not well
endowed with large, valuable mineral deposits. This is largely a function of the geology
of the province. In particular the age of the rocks and strata are much younger than in
provinces to the north. Not-withstanding, several mineral deposits are located in the
province, these remain largely undeveloped and unexploited. Most of these are not
precious metal deposits, rather they are industrial mineral related. Mineral deposits that
show promise are: stone quarrying (for export), industrial minerals related to the
building industry, such as sand, aggregate, limestone and heavy mineral sands.
2. COAL
Coal is formed when peat, or some other accumulation of partially decayed vegetable
matter, is compacted and slightly heated during burial. Coal is currently the principal
energy source in this country and likely to remain so for the foreseeable future. At
present there are no industrial applications for the low grade coal in the province.
Four coal seams are recognized in the Molteno Formation, which is the coal-bearing
horizon in the Eastern Cape Province. All seams cap upward-fining fluvial sequences and
they are named (from the base) the Indwe, Guba, Molteno and Gubenxa seams. The
Indwe seam is widely, though sporadically distributed throughout the western and
southern areas of the coalfield. The seam contains many mudrock partings and the coal
is predominantly dull; thicknesses range up to 4,3 m north of Indwe (including mudrock
partings). The Guba seam is best developed southwest of Indwe where as much as 1,8
m of clean coal occurs. The higher quality coal is located in the lower part of the seam.
The Molteno seam varies in thickness but is generally thin; widths in excess of 0,6 m are
only sporadically encountered. The Gubenxa seam attains its optimum development
about 30 km southeast of Elliot, with a maximum thickness of about 1,8 m. It lies some
30-40 m above the Molteno seam and is shaly, containing no more than 40% of clean
coal at most localities.
Dolerite intrusives are common, forming ~30% of the surface area in the Molteno Dordrecht -Indwe region. Dykes are typically 5-10 m in width and rarely exceed 10 km
along strike; dips are vertical to sub-vertical. Dolerite sills and sheets are extensive and
may approach 200 m in thickness, causing updoming of the strata in some localities. An
indication of the characteristics of coals in the Molento, Dordrecht and Indwe districts of
the Molento Coalfield are given below, washed at relative density (RD) of 1,8 (air dry).
Seam
CV(%)
H²O(%)
Ash(%)
VM(%)
F.C.(%)
Sulphur(%)
Gubenxa
22,7
1,46
40,03
18,46
56,44
0,56
Indwe
23,25
1,65
30,06
14,89
53,40
0,45
Guba
21,25
2,22
32,45
8,87
40,03
0,64
Table 1. Generalised coal qualities in the Eastern Cape Province.
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SECTOR
RAW
SITU
IN
SALEABLE
DEMONSTRATED
RESERVES
Wodehouse
13,9
1,6
Molteno
68.9
8,0
Gub
a
180.
2
24,0
Ind
w
112.
7
13,3
Tot
al
375
,7
46,9
Table 2. Resources for the Molteno coalfield.
The high ash content of the coals is a major disadvantage; washing at low RD to reduce
the ash content is not feasible since yields are very poor. The rank of coals in the
Molteno coalfield generally increases from west to east and also fluctuates on a local
scale according to proximity to igneous intrusions. High volatile bituminous coals are
present in the west, but the coals are mostly low volatile bituminous to anthracitic in the
east.
Probably the most practical application of the coal would be for domestic purposes; even
then, beneficiation would be required to reduce the ash contents.
The coal resources in this province are indicated in Table 2 (Mt). Most recently coal has
been mined at Cypergat near Molteno and on a very small scale from the Magubeni Mine
in the Magubeni valley. Neither operation is still formally in operation.
3. LIMESTONE
The farms “Schelm Hoek” and “The Downs”, near Port Elizabeth, have recently been
prospected with respect to their limestone resources. Limestone is a critical feedstock
material in the production of cement. Fossil calcretised beach horizons are the target
horizons here. Prospecting and evaluation is in progress. Limestone has been mined
from the farms Coegas Kop 316 and Limebank 173. Further development is likely.
Limestone is present in the Gamtoos Group of the Gamtoos valley, and in the EastLondon area. There are large reserves in the Alexandra area, but these are currently too
far away from markets to be viable. ‘Specialised’ limestone exists as travertine in the
Port St. Johns area. This may have an application in the manufacture of ornaments, tiles,
etc.
4. MINERAL SANDS
Numerous heavy mineral sands deposits have been reported and proved along the
Eastern cape Coastline, in particular along the coastline of the former Transkei. The
major zones of occurrence are the Wavecrest coastal area, Xolobeni, Mgazana river
Mouth and Port St Johns. The indicated resource is:
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TONNES
770 Mt
3-11%
ILMENITE
0,16-0,23%
RUTILE
0,21-0,39%
ZIRCON
A further 50 Mt is estimated to occur offshore with estimated grades of 3% ilmenite,
0,155 rutile and 0,15% zircon.
5. BASE AND PRECIOUS METALS
The well documented Nsizwa deposit contains subeconomic grades of Ni-Cu and Platinum
group metals hosted as disseminated sulphides in the basal olivine gabbro onthe Nsizwa
layered igneous complex. Although extensively prospected in the past without success,
this deposit continues to attract the attention of explorationists, mainly because of its
favourable geologic setting.
6. INDUSTRIAL MINERALS
Both brick and ceramic clays are important resources in this region. Brick clay is quarried
at several localities from weathered shales in the lower part of the Dwyka Formation.
Marine and estuarine clays in the Port Elizabeth region are extracted from the Sundays
River Formation and is of marginal quality.
Extensive kaolin deposits in the
Grahamstown area are derived from the weathering of the Dwyka Formation, Witteberg
shales and from the Prince Albert shale. This material is used in the production of wall
tiles, pottery ceramics and sanitary ware.
7. BUILDING STONE
Dolerite sills extensively intrude the sediments of the Karoo basin and where thick have
formed a medium grained melano-gabbro. This product is referred to as “black granite”
in the dimension stone trade and further potential should exist in this province. The
close proximity to the sea and coastal ports will be a favourable factor. The best known
‘black granite’ is present at Willowvale in the Transkei. Numerous small quarries have
mined stone aggregate for construction purposes in the Port Elizabeth, Cradock, Aliwal
North, Cathcart, Humansdorp, Stutterheim and Cambridge areas. The source of material
is usually either dolerite intrusives or quartzites.
29