EXCLUSIVE PROSPECTING LICENCE EPL 5133 Elandsdraai...2.1.2. Arus Formation The stand-alone, Arus...
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EXCLUSIVE PROSPECTING LICENCE EPL 5133
Elandsdraai Lead-Silver, Sedimentary Hosted Uranium & Tin
Karas Region (Warmbad Area)
Compiled & Edited by:
JUNE 2013
Proponent (Owner of Licence): PO Box 4418 Windhoek NAMIBIA; Mobile: +264811497777; Fax: +264 61 2848362; Fax2Email: 0865045683 ;
Email: [email protected]; Skype: charlienamibia ; Twitter: charlienamibia ; Website: http://www.science-development.com
Benjamin Mapani (Ph.D, Melbourne) Associate Professor Geology
University of Namibia, Private Bag 13301, 340 Mandume Ndemufayo Ave, Pionierspark, Windhoek, NAMIBIA
Faculty of Science, Data & Interpretation
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ABSTRACT
The area is named after the well-known Elandsdraai Lead-Silver deposit (84%
Pb and 340 g/t silver) which falls within this EPL, and is similar to the
neighbouring Boskiesbank – Tantallite Valley REE rich (Tantalum & Niobium)
Region and also shares a similar 380 ppm Uranium signature.
In addition to known Tin occurrences, the area reveals Pegmatites hosted
Niobium-tantalum-lithium-beryllium and REE as well as what appears to be an
iron rich sedimentary unit or pyrrhotite rich sulphide layer, that is of
sedimentary origin. The alternating felsic and mafic gneiss may be attributed
to the observed signature. All the above occurrences are expected in this
renowned REE region, and futhermore, it is strongly believed that further
exploration would most likely improve the mineral abundance considering the
proximity & similarity to the neighbouring well-explored Tantallite Valley.
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Table of Contents
1. Introduction .................................................................................................................................... 3
1.1. Location and infrastructure .................................................................................................. 3
1.2. Farms overlain by the EPL 5133 .......................................................................................... 4
1.3. Climatic condition ................................................................................................................... 5
2. Geology ........................................................................................................................................... 6
2.1. General geological settings ................................................................................................... 6
2.1.1. The Namaqua Metamorphic Complex ............................................................................ 6
2.1.2. Arus Formation ............................................................................................................... 7
2.1.3. Granites ........................................................................................................................... 8
2.1.4. Nama Group .................................................................................................................... 9
2.1.5. Kuibis Subgroup ............................................................................................................ 10
2.1.6. Schwarzrand Subgroup ................................................................................................. 10
3. Mineral Economics ........................................................................................................................ 12
3.1. Mineral Potentials within the Warmbad/Bokiesbank vicinity .............................................. 12
3.2. Known mineral occurrences/deposits within the Warmbad/Bokiesbank vicinity ............... 13
3.3 Mineral occurrences/deposits within the EPL 5133 ............................................................. 15
3.3.1 Sediment-Hosted Uranium ............................................................................................... 15
3.3.2 Elandsdraai Lead-Silver ..................................................................................................... 15
4. Conclusion ..................................................................................................................................... 19
5. Recommendation .......................................................................................................................... 20
6. Reference ...................................................................................................................................... 21
List of Figures
Figure 1: Locality and Infrastructure map ............................................................................................... 3
Figure 2: Farm Map ................................................................................................................................. 5
Figure 3: Geological Map ...................................................................................................................... 12
Figure 4: Mineral Map (above) and Total magnetic Intensity (TMI) Map ............................................ 14
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1. Introduction
1.1. Location and infrastructure
The concession EPL 5133 is located in the southern-east part of Namibia, about 50 km
south-east of Karasburg Town and 55 km east of Warmbad Village.
The property can be accessed via the track/main road B3 from Karasburg Town and
access within the concession area can be made via the gravel road D237. Access to the
railway is available within the property as the railway runs through the property.
Figure 1: Locality and Infrastructure map
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The property is large enough to sustain the facilities required for a mining operation,
and tailings disposal facility. Sufficient water can be obtained for the exploration stage
by drilling water boreholes; however at this point it is not known whether sufficient
water to sustain a mining operation is available on the property. Keetmanshoop,
Karasburg and Warmbad are the nearby populated towns and can therefore be a source
of mainly unskilled labour. Equipment and supplies are more readily available locally,
and if specialized items are not available in Namibia, they can be outsourced regionally,
e.g. from South Africa.
1.2. Farms overlain by the EPL 5133
The EPL area overlies partially several commercial farms, notably: Ondermatjie,
Blyderverwacht, Bokkiesbank Ost, Elandsdraai, Kentucky, Austerlitz, Uheib, Tzamab-
Grundorn, Vlissingen, Heiragabis, Hogies, Duurdrift, and Nababis (figure 2.)
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Figure 2: Farm Map
1.3. Climatic condition
The area has a semi-arid climate and experience occasional thunderstorms during the
summer rainfall months; November to April, giving an annual rainfall ranging between
100 to 150 mm/year. The area can be described as Semi-desert land, characterized by
grasses and scattered shrubs. The average sunshine hours per day, ranging between 9-
10 hours, that results in an annual average temperature 20 - 21 oC. The high
temperature condition causes a high average annual evaporation between 3400 – 3600
mm per annum.
Table 1: Climate (Mandelsohn et al, 2003)
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Average annual rainfall (mm/a) 100-150
Variation in annual rainfall (%) 50-60
Average in annual evaporation (mm/a) 3400 - 3600
Water deficit (mm/a) 2301 - 2500
Average hours of sunshine per day 9 - 10
Average annual temperature (°C) 20 - 21
2. Geology
2.1. General geological settings
The area is composed of four main geological units, rocks of the Arus Formation of the
Mesoproterozoic Namaqua Metamorphic complex which are intruded by Eendoorn and
Naros Granites, sediments of the Ediacaran to early Cambrian Nama group, and
Quaternary and alluvial sediments. Two gneisseic units of the Arus Formation, namely
the Umeis and Hoogoor succession are exposed on the south-western part of the EPL.
The successions consist of magmatic and leucocratic gneisses respectively. Most parts of
the EPL are covered by sediments of the Kuibis subgroup (cratogenic and initial
orogenic siliclasitics with carbonates) and the Schwarzrand Subgroup (largely distal
flysch, carbonates, with the first molasse sediments) of the Nama Group. The
Quaternary sediments consist of sand, gravel, and calcrete.
2.1.1. The Namaqua Metamorphic Complex
The Namaqua Metamorphic Complex forms a belt of high-grade Mesoproterozoic
gneisses between 100 and 400 km wide and extends across the width of southern
Africa. This belt has been variously referred to as the Namaqua Belt or the Namaqua-
Natal Belt or the Namaqua Mobile Belt. The north-western end of the belt underlies
much of southern Namibia. Mesoproterozoic continental reconstructions show the
Namaqua Belt to have been continuous with very similar gneisses of the same age in the
Grenville Belt of Canada (Hoffman, 1992). The complex consists of various pretectonic
rocks as old as 2000 Ma and abundant syn-tectonic plutonic rocks, mainly granitic in
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composition, which were emplaced and deformed during the Namaqua high-grade
tectonothermal event at ~1200 Ma (Miller, 2008). In order to understand the province,
its distinctive domains and their structural, metamorphic, temporal and tectonic
evolution, it is necessary to distinguish pretectonic, early syn-tectonic, syn-tectonic, late
syn-tectonic and post-tectonic rock units throughout.
The Namaqua Belt is one of a series of orogenic belts, now deeply eroded, that formed
during the Kibaran Orogeny in Central and Southern Africa (Clifford, 1970). Age data
from the high-grade, pre-Damaran basement granitic gneisses in the Central Zone of the
Damara Orogen suggest that the NE trending Kibaran Belt of Central Africa extended
down into this region of Namibia. The Namaqua Metamorphic Complex sensu stricto is
made up of deeply eroded, high-grade metamorphic rocks, mainly various granitic
gneisses. The syntectonic rocks of the Namaqua Metamorphic Complex fall into the
same age bracket as the bulk of the Sinclair Supergroup volcanic successions and their
subvolcanic intrusives. The oldest Sinclair rocks, the Kairab Formation and its
associated subvolcanic intrusive rocks, are however, older than the oldest syntectonic
Namaqua rocks and record the earliest magmatic activity in the Namaqua belt (Miller,
2008).
2.1.2. Arus Formation
The stand-alone, Arus Formation is a slightly migmatised metapelite unit consisting
largely of garnet-sillimanite-cordierite-biotite gneiss and unfoliated, equigranular
granulite. Rocks occur in the cores of synforms and form gradational contacts to the
underlying Guadom Formation. Original mapping has illustrated the presence of three
rock gneisses i.e. the, Jerusalem Formation, Umeis Formation and Hoogoor Formation,
but the Jerusalem Formation is not exposed on the EPL 5133.
The gneiss is usually finely banded by alternating mafic bands and light coloured
quartz-feldspar-sillimanite bands. Garnet poikiloblasts can reach 5 cm in size in the
gneiss but only 1 cm in the granulite. The weather-resistant garnets give the latter rock
a knobby appearance. The garnet contains inclusions of sillimanite, biotite and green
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pleonaste spinel and is often enclosed in cordierite or surrounded by biotite. Sillimanite,
either in the form of fibrolite or short prismatic crystals, is commonly enclosed in biotite
or cordierite. Feldspar content is highly variable and microcline or plagioclase (An28-
42) can be entirely absent. Small inclusions of sillimanite, biotite and quartz are often
present in the groundmass microcline. Bent twin lamellae in the feldspars are common.
Rare diopside, where present, is enclosed in a corona of garnet. The chemical
composition of these rocks is very similar to that of various shales (Beukes, 1973).
2.1.3. Granites
2.1.3.1. Eendoorn Granite
This granite is tectonically foliated, coarsely porphyritic syenogranite to monzogranite
with numerous large microcline phenocrysts up to 20 cm in length and between 8 and
30 % biotite. The K-feldspar phenocrysts are commonly oval or occasionally rather well
rounded. Aggregates of microcline and quartz form drawn out augen enclosed in a
sheath of biotite in zones of more intense foliation. The phenocrysts are either white,
cream, grey or pale green in colour or pinkish near shear zones.
The granite intrudes the high-grade and granulite facies pretectonic rocks, contains
xenoliths of these rocks and has often caused a feldspar blastesis in adjoining
pretectonic rocks. The intrusions do not have chilled margins. In places, the foliation
becomes so intense that the granite is transformed into garnet-biotite gneiss (Beukes,
1973; Toogood, 1976).
2.1.3.2. Naros Granites
The Naros Granite is dark grey, late tectonic biotite-hornblende granite that weathers to
a pale brown colour. Typically the granite is studded with numerous small basic
inclusions. The Naros Granite intruded between the D2 and D3 deformational events
and contains an S3 foliation that is weak in the centre of the body but strongly
developed along its margins. NE- to NNE-trending shear zones of D3 age or younger
form the borders to the Granite.
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A few xenoliths of leucocratic rocks are present and the granite has weakly foliated
central parts but strongly foliated margins in which the xenoliths are markedly
flattened. Thin, white, leucocratic granitic veins ramify through parts of the more
massive granite or are parallel to the foliation in the margins of the granite.
Migmatization has resulted in the development of foliation axial planar to folded
migmatitic leucosomes (Toogood, 1976). This granite may be approximately time
equivalent to the Warmbad Granite.
2.1.4. Nama Group
The Ediacaran-early Cambrian Nama Group was deposited on an extensive peneplain on
the southern foreland of the Damara Orogen. The Nama Group represents a foreland
succession composed of initial cratogenic sandstones and shales derived largely from
eastern source terrains of the Kalahari craton. This initial veneer of a few tens of metre
thickness is overlain by over 1 kilometre of distal orogenic flysch and intercalated
shallow-marine carbonate that prograded basinward from the foreland peripheral
bulge. Siliciclastic sediments at this time were derived from the Damara and Gariep
Orogens to the north and west, demonstrated by thickening wedges of shales and sands
(DiBenedetto and Grotzinger, 2005). The final phase of foreland basin filling is marked
by deposition of over 1 kilometre of orogenic molasse, represented by fluvial and
shallow marine siliciclastic facies which terminated earlier carbonate deposition.
Most of the Nama strata dip at 1° or less to the east, but were affected by folding and
thrusting onto the foreland along the northern and western margins of the basin during
the final stages of Damara and Gariep orogenesis, including the youngest molasse
succession. Fine-grained white micas formed in all the Nama sedimentary rocks during
the final peak of Damaran regional metamorphism.
The Nama Group of the Warmbad area is divided into lower Kuibis Subgroup
(cratogenic and intial orogenic siliclasitics with carbonates), middle Schwarzrand
Subgroup (largely distal flysch, carbonates, with the first molasse sediments forming the
upper most part) and an upper Fish River Subgroup (molasse succession). Only the
Kuibis Subgroup and the Schwarzrand Subgroup are exposed on the the area (EPL
5133).
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2.1.5. Kuibis Subgroup
Lithostratigraphically the Kuibis Subgroup is divided into the Dabis and Zaris
Formations (undifferentiated on the map). It comprises at least four depositional
sequences. Kuibis Subgroup consists of conglomerate, sandstone, limestone and shale
interpreted as a westward prograding alluvial system. Grains of quartz and feldspar are
common in the carbonate and are partly replaced by carbonate. Although the Subgroup
is not subdivided on the 1:250 000 geological map, its formations are briefly described
in the following.
2.1.5.1. Dabis Formation
The Dabis Formation forms the base of the Kuibis Subgroup, which is subdivided in to
the lower Kanies Sandstone Member, the middle Mara Limestone Member and the
upper Kliphoek Sandstone Member, but no such distinction has been made in the map
area. The lower sandstone and middle limestone members form the first depositional
sequence, while the upper sandstone unit represents the base of the second sequence
(Saylor et al., 1995).
2.1.5.2. Zaris Formation
The Zaris Formation follows upon the Dabis Formation and consists of the Mooifontein
Limestone Member and the Urikos Shale Member (not distinguished on map). The
Mooifontein limestone forms the upper part of the K2 depositional sequence, whose top
is marked by an erosional unconformity, while the fine-grained sediments of the Urikos
Member represent the recessive periods between carbonate-dominated intervals.
2.1.6. Schwarzrand Subgroup
The green and red shale and sandstone with blue limestone of the Schwarzrand
Subgroup are seen as tidal flat, distal alluvial plain and fan delta complexes with a
carbonate platform. From the base up the Schwarzrand Subgroup consists of the
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Nudaus, Urusis and Nomtsas Formations (Germs, 1983; Saylor, 1996; Saylor et al.,
1995), which were laid down in at least five depositional sequences.
2.1.6.1. Nudaus Formation
This unit consists of the Niederhagen quartzites and shales, overlain by the Vingerbreek
shales, although on the 1: 250 000 map it is shown as undifferentiated. The Nudaus
Formation represents the first depositional sequence of the Schwarzrand Subgroup.
2.1.6.2. Urusis Formation
The Urusis Formation in the Witpütz Sub basins consists, from the base upwards, of the
Nasep Sandstone Member, the Huns Limestone Member, the Feldschuhhorn Shale
Member and the Spitskop Limestone Member.
2.1.6.3. Nomtsas Formation
The Nomtsas Formation forms the base of the molasse succession in the Nama Basin. It
comprises the earliest Cambrian strata recorded in Namibia (Grotzinger et al., 1995), as
well as contains the first Cambrian trace fossils. A volcanic ash in the lowermost
Nomtsas Formation yields an age of 539.4 ± 1 Ma. The lower part of Nomtsas Formation
consists of conglomerate, grit and sandstone which pass upwards into marine siltstone,
pebbly siltstone and shale. The conglomerate in the Witpütz area is overlain by green
pebbly and pebble-free siltstone interpreted as well mixed gravity flow deposits. These
are followed by pebble-free siltstones that grade upwards into a shoaling succession of
interbedded siltstone and fine-grained, planar-bedded to low-angle cross-bedded and
ripple marked sandstone (Saylor et al., 1995), which originated as debris flows. Much of
the upper part of the formation is made up of well developed, trough cross-bedded
sandstone deposited in a braided fluvial environment. These sandstones thin and pinch
out into the Witpütz Sub basin. The uppermost unit consists of interbedded sandstone
and shale.
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Figure 3: Geological Map
3. Mineral Economics
3.1. Mineral Potentials within the Warmbad/Bokiesbank vicinity
- Tin associated with Cassiterite bearing pegmatite intrusion, REEs associated
with local alkaline complexes, dykes, plugs and pegmatites.
- Lead – Fluorite: Hosted in Umeis succession porphyroblastic biotite gneiss of
the Namaqua Metamorphic Complex.
- Tungsten: Is known to occur at several localities in the Namaqua Metamorphic
Complex.
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- Copper/Nickel hosted in Kum-Kum mafic units and associated with
clinopyroxene.
- Niobium-tantalum-lithium-beryllium and REEs occurs in pegmatites found on
the farms Sandfontein 131.
3.2. Known mineral occurrences/deposits within the
Warmbad/Bokiesbank vicinity
- Tantalite Valley Complex: Hosts several mineral deposits, including Tantalite-
Columbite, Niobium, Tin, Tungsten, Copper and Nickel. Resources calculation
include 60 000t lepidolite containing 2 to 3 % Li2O. Tantalite-Columbite has
assayed at 67.85 % Ta2O5, 15.73 % Nb2O5, 1.09 % TiO2, and 0.16 % SnO2.
- Bokkiesbank Tin: An isolated cassiterite bearing pegmatite, intrude in to rocks
of the Namaqua Metamorphic Complex.
- Kumkum Copper-Nickel: Copper-Nickel mineralisation associated with mafic
intrusives. Mineralisation is hosted in a shear controlled quartz vein of the Umeis
Succession near a contact with the Eendoorn granite.
- Jerusalem Fluorite: A series of near vertical quartz-carbonate-fluorite veins
emplaced along northeast-trending shears. Surrounded by gneiss of Namaqua
Metamorphic Complex. Resources evaluation of 5445 tons fluorite mined, 800
tons shipped for testing, the rest stockpiled.
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Figure 4: Mineral Map (above) and Total magnetic Intensity (TMI) Map
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3.3 Mineral occurrences/deposits within the EPL 5133
The property has two main mineral occurrences of economic potential, and the deposits
are described below.
3.3.1 Sediment-Hosted Uranium
A sediment –hosted uranium anomaly occurs on the farms Bokkiesbank Ost 79. An
anomaly of 380 ppm and 390 ppm U+Th have been recorded. These require further
proving to ascertain tonnage.
3.3.2 Elandsdraai Lead-Silver
Thin veins containing barite, fluorspar, and galena with calcite cut through a sandstone-
conglomerate at the base of the Kuibis beds that lie unconformably on the Namaqua
Metamorphic Complex meta-sediments and granites. A galena sample contained 84%
Pb and 340% g/t silver.
Based on the existing regional geological data sets from the Geological Survey of
Namibia (GSN) as well as the known mineral occurrences within the vicinity, the
property has a potential to host Nuclear Fuel, base metals, precious metals, and
Industrial Minerals deposits.
The aero-magnetic data (Fig 4) of this area shows high magnetic responses in a form of
linear features from north east side of the EPL to south west side. A ring type structure
is observed within nearly the center of the EPL. High magnetic respond are associated
with magnetic minerals, it is therefore suggesting a great need to conduct exploration
investigation around this area as would enhance potential discovery of base metal and
precious metal deposits.
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Figure 5. 1st Vertical derivative Image.
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Figure 6. Digital Terrain Model.
Figure 7. Uranium radiometric data image.
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Figure 8. Thorium radiometric data.
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Figure 9. Potassium radiometric data.
Radiometric data shows that K, U and Th all match. This could mean an association of
granitic origin. Uranium in the area occurs and an occurrence of 390 ppm was
discovered by previous explorers.
4. Conclusion
Based on desktop study covering literature review of all available geological and
geophysical information and data sets pertaining to previous exploration activities in
the surroundings area, the EPL 5133 has a potential for the following.
- Sediment-Hosted Uranium deposit: A sediment –hosted uranium occurrence
is found on the EPL, occuring in the basal conglomerate. An anomaly of 380 ppm
and 390 ppm U+Th have been recorded. The TMI and the VD geophysical image
shows that there is a lower pluton intruding in the EPL which may not be
exposed at the surface. The prospectivity for uranium is much higher, and
weathering occurred from north towards south oft he EPL area.
- Lead-Silver deposit: Elandsdraai Lead-Silver occurrence that need to be
explored in details. Sample analysis of galena indicate 84% Pb and 340% g/t
silver.
- Tin associated with Cassiterite hosted in pegmatites that intrudes the Namaqua
Metamorphic Complex.
- Lead – Fluorite in Umeis succession porphyroblastic biotite gneiss of the
Namaqua Metamorphic Complex;
- Pegmatites hosted Niobium-tantalum-lithium-beryllium and REE.
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5. Recommendation
A list of recommendations to be undertaken during the exploration phase;
Data set gathering;
- Acquire all geological, geochemical and geophysical data set from the Geological
Survey of Namibia (GSN). The data set include all geological maps, Aerial
photographs, satellite images, geochem plots and geophysical filters.
Data set Interpretation;
- An integrated Geological, Geochemical and Geophysical data interpretation
should be carried out to delineate exploration targets.
Ground Truthing Exploration;
- Reconnaissance and field based mapping is recommended to map out all
geological units on local scale since the area was only mapped on regional scale
by the (GSN). Focus on Elandsdraai lead-silver occurrence and sediment hosted
uranium occurrence found within the EPL area.
Soil/Rock chips/Trench sampling;
- Soil & Rock chips sampling should be carried on the delineated exploration
targets and all existing trenches that were dug by previous exploration work
should be sampled for analysis.
Ground Geophysics;
- A ground geophysical survey should be carried out on the anomalies delineated
from airborne survey data. Mainly ground radiometric survey on the sediment
hosted uranium anomalies.
Total Magnetic Intensity Anomaly Explanation
By B.S. Mapani
The TMI image given above, show a roughly NW-SE trend. This trend mimics the trend
of poorly exposed basic rocks. However to the SE, the magnetic intensity is much more
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intense. This may be a combination of either sulphide or Fe-ore type BIF mineralization.
However all TMI anomalies require further investigation, either with IP (Induced
polarization) or resistivity method. This is a requirement which would yield a result
and enable us to correctly interpret the anomalies.
Way Forward.
The current dataset reveals that sedimentary hosted uranium occurs in the area. The
second stage is a detailed geological mapping and trenching exercise with sampling to
obtain the anomalous zones from the surface as opposed to geophysics. After this stage,
some percussion drilling may be commenced.
The magnetic anomalies may be picked by geochemistry. This geochemical data may
yield zones of metallic affiliation in the EPL zone.
6. Reference
250 K map, Warmbad sheet no: 2818, Ministry of Mines and Energy, Geological Survey
of Namibia, Windhoek.
Air borne Magnetic data Warmbad sheet no: 2818, Ministry of Mines and Energy,
Geological Survey of Namibia, Windhoek.
Mendelsohn J. (2003), Atlas of Namibia.
Miller R. McG. (2008), Geology of Namibia, Ministry of Mines and Energy, Geological
Survey of Namibia, Windhoek.
Mineral Resource of Namibia (1992). Ministry of Mines and Energy, Geological Survey
of Namibia, Windhoek.