Uranium Ore Deposits

Topic 5: Uranium Ore Deposits
Hassan Z. Harraz
hharraz2006@yahoo.com
2012- 2013
This material is intended for use in lectures, presentations and as
handouts to students, and is provided in Power point format so as to
allow customization for the individual needs of course instructors.
Permission of the author and publisher is required for any other usage.
Please see hharraz2006@yahoo.com for contact details.
Prof. Dr. H.Z. Harraz Presentation

Outline of Topic 5:
We will explore all of the above in Topic 5.
 Uranium as an Element
 Radioactive Elements:
 Uranium Occurrences
 Uranium Minerals
 Uranium Ore Miner
 Uranium Geology
 Categories of Uranium Deposits:
1) Unconformity-related Deposits
2) Breccia complex deposits
3) Sandstone deposits
4) Quartz-pebble conglomerate deposits
5) Limestone deposits
6) Surficial deposits
7) Volcanic deposits
8) Intrusive deposits
9) Metasomatite deposits
10) Vein deposits
11) Phosphorite and Lignite deposits
 Uranium Resources
 Production from mines
 Known Recoverable Resources
 Types of Uranium Deposits in Egypt:
 Main Occurrences:
1) Gabal Gattar uranium
2) Uranium deposits of Um Ara area
 References

Uranium as an Element
 The heaviest naturally occurring element
(three main isotopes U-234, 235-0.71%, 238-99.28%)
 U+4 (reduced-insoluble) & U+6 (oxidized-soluble)
 Uranium (U) has a large atom that does not "fit" into most silicate
structures, and is therefore concentrated in the magmatic fluid after
most of the magma has crystallized, where it enters the structures of
zircon and sphene in granites and pegmatites. For economic deposits of
U minerals to form, U has to be leached out of its host rock, mobilized,
then re-deposited, as is the case with vein deposits. Alternatively, the
concentration of U has to reach a high enough level in the residual fluid
of magmatic crystallization, that U minerals can crystallize directly out
of the magmatic fluid and will occur disseminated in granites and
pegmatites.
 Uranium occurs in a number of different igneous, hydrothermal and
sedimentary geological environments.

Radioactive Elements
 In radioactive elements, the configuration of the nucleus is unstable, and breaks down, emitting radioactive “decay”
products:
alpha, beta and gamma radiation.
 Isotopes of an element have nuclei with the same number of protons but different numbers of neutrons.
 Some isotopes are stable, and others subject to radioactive decay.
 The natural radioactivity of rocks stems mainly from their contents of U, Th and K40 (K40 represents 0.0118% of total
potassium). Natural uranium consists mainly of the isotope U238 (99.3 %) with a small amount (~ 0.7 %) of U235, but U234 is
found in a minute quantity, formed as one of the steps in the decay of U238. Both U238 and U235 decay through a series of
short lived radioactive isotopes to end with stable isotopes of lead (Pb206 from U238 and Pb207 from U235).
 Uranium and thorium are members of the actinide family. Their ionic radii decrease with increasing atomic number. The
two elements can extensively substitute each other, which explain their geochemical coherence during magmatic
crystallization. U and Th are of high atomic numbers (92 and 90 respectively), have large ionic radii, high ionic charge and
relatively low concentration compared with the other natural elements. They are kept in the magma in a frozen state until
the late magmatic and hydrothermal stages. During these stages, they can compete with other elements for which they
can substitute such as Zr+4, Ce+4, Y+3 and Ca+2 and/or form minerals of their own (e.g. uraninite, thorite and thorianite).
Modified from http://en.wikipedia.org/wiki/Alpha_particle
Helium nucleus
Electron
Energy
(electromagnetic
radiation)
Alpha radiation is readily
stopped by a sheet of paper.
Beta radiation is halted by an
aluminium plate.
Gamma radiation is eventually
absorbed as it penetrates a
dense material. Lead, being
dense, is good at absorbing
gamma radiation – several
centimeters of thickness is
needed.
4Prof. Dr. H.Z. Harraz Presentation

Uranium Occurrences
 Uranium occurrence:
 Uranium present almost everywhere, but in low concentrations
 Natural concentrations in rocks: 0.0X (alkalic) – X (acidic) ppm
 Concentration of uranium in the environment
> URANIUM DEPOSIT
 Uranium is a naturally occurring element that has the highest atomic weight (~238 g/mole) and is slightly
radioactive.
 It can be found in minute quantities in most rocks, soils and waters (normally < 5 ppm), but the real
challenge is to find it in high enough concentrations to make it economically feasible to mine.
 Uranium is easily oxidized and forms a number of common uranium oxides and oxy-hydroxide like
uraninite (or pitchblende) and schoepite (including meta- and para-).
 Uranium can be found in soils and waters due to the breakdown (weathering) of rocks containing it. Once
it is in the soil and water, it can be taken up by plants and consumed by people or grazing animals, or it can
dissolve in the water to be consumed by any organism..
5
Table 1: Average uranium concentrations in ores, rocks and
waters (ppm - parts per million).
Material Concentration (ppm U)
High-grade orebody (>2% U) >20,000
Low-grade orebody (0.1% U) 1, 000
Average granite 4
Average volcanic rock 20 - 200
Average sedimentary rock 2
Average black shale 50 - 250
Average earth's crust 2.8
Seawater 0.003
Groundwater >0.001 - 8
Geiger Counter Readings at Eva - former uranium mine

Basic Geochemistry, Mineralogy
 Uranium normally occurs in 2 valence states: reduced +4 and oxidized +6
 Uranous ion: U+4 is quite insoluble
 Uraninite: UO2 [- U3O8 w/ 1%+ Th & REE]
 Pitchblende if fine-grained, massive
Density 6.5-8.5
 Coffinite: U(SiO4)1-X(OH)4X
 Brannerite: (U,Ca,Ce)(Ti,Fe)2O6
Density 4.5-5.4
 Uranyl ion: U+6 is quite soluble and forms many stable aqueous complexes and
then minerals when additional cations become available
 Carnotite: K2(UO2)2 (VO4)2 • 3H2O
 Tyuymunite: Ca(UO2)2 (VO4)2 • 5-8H2O
 Autunite: Ca(UO2)2 (PO4)2 • 10H2O
 Tobernite: Cu(UO2)2(PO4)2 • 12H2O
 Uranophane: Ca(UO2)2SiO3(OH)2 • 5H2O
 Complexes with: CO3 =, OH-, H-, PO4 =, F-, Cl
Pitchblende (black), or uraninite,

Uranium Minerals
Oxides: uraninite (crystalline UO2-2.6), pitchblende
(amorphous UO2-2.6)
Silicates: coffinite (U(SiO4)1-x(OH)4x)
Phosphates
Organic complexes & other forms
Uranium can be found in a large number of
minerals (WebMineral has an excellent listing of
them in order of uranium concentration).
The most common economic minerals are listed
below (click on the links to see photos and
additional information on these minerals):
Uraninite (crystalline UO2-2.6)
Pitchblende (amorphous UO2-2.6)
Uranophane (CaO, 2UO2 , 2SiO2, 6H2O)
Carnotite (K2O, 2UO2, 2VO4)
Coffinite(U(SiO4)1-x(OH)4x)
Autunite
torbernite
7
Autunite
Torbernite

Eh-pH and Uranium Solubility
8
Reduced
Oxidized
Now add: Cl, S, P, F, …

In Oxidizing Groundwater
9

Uranium Ore Minerals
 Primary ore mineral
 The major primary ore mineral is uraninite or pitchblende (UO2 + UO3, nominally U3O8),
though a range of other uranium minerals is found in particular deposits.
 These include
 Carnotite (uranium potassium vanadate),
 Davidite-brannerite-absite type uranium titanates, and
 Euxenite-fergusonite-samarskite group (niobates of uranium and rare earths).
 Secondary uranium minerals :
 A large variety of secondary uranium minerals is known, many are brilliantly coloured and
fluorescent.
 The commonest are:
 Gummite (a general term like limonite for mixtures of various secondary hydrated
uraniuim oxides with impurities);
 Hydrated uranium phosphates of the phosphuranylite type: including autunite (with
calcium), saleeite (magnesian) and torbernite (with copper); and
 Hydrated uranium silicates: such as coffinite, uranophane (with calcium) and
sklodowskite (magnesian).
10

Uranium Deposits
Through Time
11

Uranium Geology
Source rock of uranium (X ppm) > process of removal > concentration in
favorable conditions (X000 ppm) > ?URANIUM DEPOSIT
Uranium occurrence: A naturally occurring, anomalous concentration of
uranium
Uranium deposit: A mass of naturally occurring mineral from which uranium
could be exploited at present or in the future (under given economic
conditions)
12
 Types of Uranium Deposits
 Uranium deposits occur in many different rock types from sedimentary to
volcanic.
 One thing almost all economic uranium deposits have in common is that the
uranium is remobilized from one area (i.e., leached from a source rock
containing minute quantities of U or as mineral grains with elevated U
concentrations) and re-precipitated in a host rock where chemical
conditions (reducing) are conducive to concentrating the uranium in higher
concentrations or re-deposited due to water action (waves on beaches or
water flow in rivers) in placer deposits.

Types of U Deposits
 Unconformity type (39%)
 Sandstone or ‘Roll Front’ (29%)
 Metasomatic (10%)
 Hematite breccia type (9%)
 Volcanic (8%)
 Paleoplacers (2%)
 Igneous (1%)
 [percentages are production in 2004]
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U Ore Deposits
13

Categories of Uranium Deposits
 Uranium deposits world-wide can be grouped into 14 major categories of
deposit types based on the geological setting of the deposits (OECD/NEA &
IAEA, 1996). Australian uranium deposits can be grouped into 6 of these
categories, with some mineralization in two further ones. Most of Australia's
uranium resources are in two kinds of orebodies, unconformity-related and
breccia complex, while sedimentary deposits are less significant than
overseas.
1) Unconformity-related deposits (Canada, Australia)
2) Hematitic Breccia complex deposits (only Australia – Olympic Dam)
3) Sandstone deposits (all over the word)
4) Paleoplacer (Quartz-pebble conglomerate) deposits
6) Surficial deposits (USA, Australia, Canada and Namibia)
8) Intrusive deposits (Namibia)
10) Vein deposits (all over the word)
11) Phosphorite and Lignite deposits (USA)
14

 An unconformity is time gap in the rock record between two rock units where the lower unit may be
deformed, brecciated or altered and the overlying units are less deformed.
Uranium deposits can occur in the underlying or overlying units. In the underlying units, there may be a
weathering zone, fault zone or some other feature that increases the rocks porosity and permeability. In
the overlying units, it may be the sandstones or some other features that allows the concentration of
uranium.
 Unconformity-related deposits arise from geological changes occurring close to major unconformities.
Below the unconformity, the metasedimentary rocks which host the mineralisation are usually faulted
and brecciated. The overlying younger Proterozoic sandstones are usually undeformed.
 Deposits of this type are common in Australia, Canada and India
 Unconformity-related deposits constitute approximately 33% of the World Outside Centrally Planned
Economies Area (WOCA)'s uranium resources and they include some of the largest and richest deposits.
Minerals are uraninite and pitchblende. The main deposits occur in Canada (the Athabasca Basin,
Saskatchewan and Thelon Basin, Northwest Territories); and Australia (the Alligator Rivers region in the
Pine Creek Geosyncline, NT and Rudall River area, WA).
 Unconformity-related deposits- constitute a major proportion (22%) of Australia's total uranium
resources and more than 80% of Australia's total production since 1980 has been mined from two of
these deposits - Ranger #1 and Nabarlek (now mined out). Other major deposits in the Alligator Rivers
region are Ranger # 3, Jabiluka (North Ranger), Koongarra and Ranger 68.
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U Ore Deposits

 In 1996, more than 95% of Canada's total uranium production was from unconformity-related deposits -
Key Lake, Cluff Lake, and Rabbit Lake deposits. Other large, exceptionally high grade unconformity-
related deposits which are being developed for future mining include Cigar Lake (averaging 9.1% U3O8,
some zones over 50% U3O8); McArthur River (averaging 5.0% U3O8, some zones average 42% U3O8); Eagle
Point, Collins Bay A and D orebodies and McClean Lake.
 The deposits in the Athabasca Basin occur below, across and immediately above the unconformity, with
the highest grade deposits situated above (eg Cigar Lake) and across the unconformity (eg Key Lake).
 In the Alligator Rivers region, the known deposits are below the unconformity and are generally much
lower grade than the Canadian deposits. Uranium exploration in the Alligator Rivers region and Arnhem
Land has been restricted since the late 1970s because of political and environmental factors. Much of
the Alligator Rivers region and Arnhem Land have only been subjected to first pass exploration designed
to detect outcropping deposits and extensions of known deposits, eg Jabiluka 2 was found by drilling
along strike from Jabiluka 1.
 There has been very little exploration to locate deeply concealed deposits lying above the unconformity
similar to those in Canada. It is possible that very high grade deposits occur in the sandstones above the
unconformity in the Alligator Rivers/Arnhem Land area.
 The Kintyre deposit in the Rudall River area is similar to the deposits in the Alligator Rivers region.
Metallurgical tests have shown that Kintyre ore can be radiometrically sorted and upgraded prior to
milling and processing.
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U Ore Deposits

Unconformity-type Uranium
 A major portion of the world’s low cost U is in Proterozoic unconformity deposits
 This portion is increasing over time
 Typically at base of M.Proterozoic sandstone in unconformable contact with graphitic and/or pyritic L.Proterozoic
strata
 Structural control by faults or fractures
 U or U+(non-economic Ni, Co, As)
 U in basement or above unconformity
Global Distribution
 Recognized in early 1970’s almost simultaneously in:
 Athabasca Basin, Saskatchewan, Canada
 Pine Creek Basin, NT, Australia
 These 2 regions are only ones producing although there are some additional minor examples in Canada and Australia
Athabasca Basin - Setting
 Proterozoic supracrustal rocks on a crystalline basement - Trans-Hudson Orogen
 Western Craton: gneisses, granulites, local mylonites, migmatites, plutons; 2.3-1.8 Ga
 U contents: 0.05 to 14.3 ppm
 Cree Lake mobile zone: granitoid gneisses and shelf-type metasediments
 Multiple deformation stages, most highly deformed in the core zone
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U Ore Deposits
17

Unconformity-Type Deposit
Outwash sand and gravel
Till
Ore-bearing till (cobble ore horizon)
Ore body
Shear zone
Athabasca formation sandstone
Pegmatoid
Graphitic gneiss
Biotite gneiss
Block movement
-450
-500 m level
0 10 20 meters
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U Ore Deposits

Source: Natural Resource Canada
Fault and Unconformity-related Uranium Deposits
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U Ore Deposits

 Geological setting and host rocks: This type of deposit occurs as tabular to cigar - shaped bodies located
along unconformity surfaces between Middle Proterozoic or older basement (consisting of metamorphosed
marine or volcanic sediments, typically pelitic or marly in composition), and Mid - Proterozoic or younger
fluvio-deltaic coarse red sandstones and siltstones. The ore body, while concentrating along the
unconformity surface, occurs in both units, but is structurally controlled by faults and shear zones that post-
date the unconformity. In the case of the Athabasca deposit, ore bodies occur only where these faults cut
across graphite - bearing basement rocks.
 Ore minerals: Pitchblende and coffinite.
 Alteration: Chloritization, argillization, albitization and hematitization.
 Textures: predominantly open space textures.
 Temperatures: 120 - 220°C.
 Grades: typically 2% U.
 Source of U: Basement rocks.
 Origin of the deposit: These epigenetic deposits are believed to have formed when heated fluids travelling
up fault planes towards the unconformity surface become strongly reducing where the fault cuts across a
graphitic unit. The heat source is believed to be a thermal anomaly within the basement, possibly resulting
from a long period of radioactive decay. At the same time, oxidizing fluids moving along the unconformity
surface have a significant amount of U leached from the underlying basement and the overlying sediments,
which is carried in solution in the form U+6. As soon as both fluids meet and mix at the unconformity
surface, the U+6 is reduced to U+4, which then deposits as pitchblende (at the sites of the faults). Figure 5
shows a cartoon of this model.
Example: Athabasca- type U deposits:
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U Ore Deposits

Sandstone Uranium Deposit
In-Situ Recovery Well-Field, South Texas
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ATHABASCABASINHIGH-GRADE URANIUM
13 METERS 18.12% U3O8
UNCONFORMITY-STYLE URANIUM DEPOSIT
ATHABASCA BASIN, NE SASKATCHEWAN
U Ore Deposits

2) Breccia complex deposits
 Breccias are pre-existing rocks that have be broken-up into pieces by either weathering and collapse or
fracturing (hydraulic or tectonic).
 The blocks form a high porosity and permeability framework for U precipitation.
 Deposits of this type are common in Australia, United States and India.
 The Olympic Dam deposit is one of the world's largest deposits of uranium, and accounts for about 66% of
Australiaís reserves plus resources. The deposit occurs in a hematite-rich granite breccia complex in the
Gawler Craton. It is overlain by approximately 300 meters of flat-lying sedimentary rocks of the Stuart Shelf
geological province.
 The central core of the complex is barren hematite-quartz breccia, with several localised diatreme structures,
flanked to the east and west by zones of intermingled hematite-rich breccias and granitic breccias. These
zones are approximately one kilometer wide and extend almost 5 km in a northwest-southeast direction.
Virtually all the economic copper-uranium mineralisation is hosted by these hematite-rich breccias. This
broad zone is surrounded by granitic breccias extending up to 3 km beyond the outer limits of the hematite-
rich breccias.
 The deposit contains iron, copper, uranium, gold, silver, rare earth elements (mainly lanthanum and cerium)
and fluorine. Only copper, uranium, gold, and silver are recovered. Uranium grades average from 0.08 to
0.04% U3O8, the higher-grade mineralisation being pitchblende. Copper grades average 2.7% for proved
reserves, 2.0% for probable reserves, and 1.1% for indicated resources. Gold grades vary between 0.3-1.0 g/t.
 Details of the origin of the deposit are still uncertain. However the principal mechanisms which formed the
breccia complex are considered to have been hydraulic fracturing, tectonic faulting, chemical corrosion, and
gravity collapse. Much of the brecciation occurred in near surface eruptive environment of a crater complex
during eruptions caused by boiling and explosive interaction of water (from lake, sea or groundwater) with
magma.
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U Ore Deposits

Schematic Cross Section of a "Typical" Breccia Pipe
Source: The NAU Project, modified after Wenrich, Billingsley, and
Huntoon, 1986 http://northern-arizona-uranium-project.com/breccia_pipe_anatomy
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U Ore Deposits

3) Sandstone deposits Sandstone uranium deposits occur in medium to coarse-grained sandstones deposited in a continental fluvial or marginal marine sedimentary environment.
Impermeable shale/mudstone units are interbedded in the sedimentary sequence and often occur immediately above and below the mineralized
sandstone. Uranium precipitated under reducing conditions caused by a variety of reducing agents within the sandstone including: carbonaceous material
(detrital plant debris, amorphous humate, marine algae), sulphides (pyrite, H2S), hydrocarbons (petroleum), and interbedded basic volcanics with abundant
ferro-magnesian minerals (eg chlorite).
 Normally in the coarser fraction of sandstones, these units are typically deposited in marginal marine to terrestrial environments. The best deposits are
found between impermeable units and contain abundant organic debris or other material to promote the reducing conditions to cause the U to precipitate
out of solution. Deposits of this type are common in United States, Niger, Kazakhstan, Uzbekistan, Gabon, South Africa, Canada, India and Australia. Types of
deposits include:
 Three main types of sandstone deposits:
1) Roll-front deposits: arcuate bodies of mineralisation that crosscut sandstone bedding; Roll-front deposits cut across bedding. Uranium-bearing
ground waters precipitate uranium oxide minerals when they come in contact with reducing conditions in porous and permeable rocks.
2) Tabular or trend deposits : irregular, elongate lenticular bodies parallel to the depositional trend, deposits commonly occur in palaeochannels
incised into underlying basement rocks; Uranium deposits form tabular bodies that may or may not cross bedding. They are usually associated
with organic debris or pyrite. Some uranium deposits follow paleochannels or some other depositional trends. The ore can occur either as
reprecipitated deposits in reducing zones associated with pyrite or organic debris (like roll-front deposits) or as placer deposits (heavy mineral
deposits) concentrated in a beach, bar or channel due to water movement. Deposits found in USA, Japan, Niger and Canada.
3) Tectonic/lithologic deposits: occur in sandstones adjacent to a permeable fault zone. Uranium is remobilized and precipitates adjacent to
permeable fault and/or fracture zones. See figure in unconformity deposits which also shows mineralization adjacent to fault zones.
 Sandstone deposits constitute about 18% of world uranium resources. Orebodies of this type are commonly low to medium grade (0.05 - 0.4% U3O8) and
individual orebodies are small to medium in size (ranging up to a maximum of 50 000 t U3O8). The main primary uranium minerals are uraninite and
coffinite. Conventional mining/milling operations of sandstone deposits have been progressively undercut by cheaper in situ leach mining methods.
 The United States has large resources in sandstone deposits in the Western Cordillera region, and most of its uranium production in has been from these
deposits. Uranium is being recovered from in situ leach mining of sandstone deposits in the South Texas area (Texas Gulf Coast).
 Large uranium resources within sandstone deposits also occur in Niger, Kazakstan, Uzbekistan, Gabon (Franceville Basin), and South Africa (Karoo Basin).
Kazakstan has reported substantial reserves in sandstone deposits with average grades ranging from 0.02 to 0.07% U. In 1994, approximately 75% of
Uzbekistan's uranium production and 70% of Kazakstan's production was from in situ leach mining of sandstone deposits.
 Sandstone deposits represent only about 6% of Australia's total reserves plus resources of uranium .In the Westmoreland area, northwest Queensland, the
bulk of the resources are within five ore lenses in sandstones along the flanks of the Redtree joint zone. The mineralized sandstone is overlain by basic
volcanics.
 Within the Frome Embayment, six uranium deposits are known, the largest being Beverley and Honeymoon. Tests have shown that these two deposits are
amenable to in situ leach mining methods. At the Mulga Rock deposit, 230 km east-northeast of Kalgoorlie, uranium mineralisation is in peat layers
interbedded with sand and clay within a buried palaeochannel.
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U Ore Deposits

Source: Curnamona Energy
Roll-Front Sandstone Uranium Deposits
http://www.curnamona-energy.com.au/exploration.html
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U Ore Deposits

Sandstone Uranium Deposit
Open Pit, Central Wyoming
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Trend Sandstone Uranium Deposits
Source: Curnamona Energy
http://www.curnamona-energy.com.au/exploration.html
U Ore Deposits

Sandstone U in North America
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27

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U Ore Deposits
28
Grants NM Uranium Area Sandstone-Roll Front-Humate
 Pyrite-Organic-bearing, poorly sorted, fluvial or marginal
lacustrine/marine
 Colorado Plateau, Wyo, E.Texas
 U concentrates at oxidizing groundwater -reducing aquifer
interface
 Continued groundwater flow can oxidize and remobilize
precipitated minerals, only to deposit them again a few feet
down gradient - process repeats
Roll Front Development
Vertical cross section view)
Roll Front - Plan View

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U Ore Deposits
29
Cross Section or Plan View

4) Paleoplacer (Quartz-pebble conglomerate) deposits
 These deposits make up approximately 13% of the world's uranium
resources. Where uranium is recovered as a by-product of gold
mining, the grade may be as low as 0.01% U3O8. In deposits mined
exclusively for uranium, average grades range as high as 0.15% U3O8.
Individual deposits range in size from 6000-170 000 t contained
U3O8.
 Major examples are the Elliot Lake deposits in Canada and the
Witwatersrand gold-uranium deposits in South Africa. Mining
operations in the Elliot Lake area have closed in recent years
because these deposits are uneconomic under current uranium
market conditions.
 No such economic deposits are known in Australia, although quartz-
pebble conglomerate containing low-grade uraninite mineralization
exists in several Archaean-Palaeoproterozoic basins in Western
Australia. These are similar in lithology and age to the
Witwatersrand conglomerates.
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U Ore Deposits

4) Paleoplacer – (Qtz Pebble) Type
Basal portion of the Proterozoic where it directly overlies Archean basement
Quartz pebbles of variety of colors but only quartz.
Usually high in pyrite; well cemented
Uraninite, Brannerite, Monazite
 Down dip density variations support placer
 Significant remobilization obscures simple story - role of carbonaceous
material?
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31
South Africa - Witwatersrand

 Units that have high porosity and permeability (due to
tectonic or diagenetic alteration) as well as organic carbon
contents form good sites for uranium precipitation.
 Deposits of this type are rare, but can be found in United
States (Grants Mineral Belt, New Mexico).
Limestone Uranium Deposits
Source: Finch & McLemore (1989)
in McLemore (2007)
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U Ore Deposits

6) Surficial deposits
 The U is concentrated in young sediments or soils near the earth's surface. Uranium minerals precipitate out onto
the finer-grained particles or are transported particles. Associated with soil formation.
 Surficial uranium deposits are broadly defined as young (Tertiary to Recent) near-surface uranium concentrations in
sediments or soils. These deposits usually have secondary cementing minerals including calcite, gypsum, dolomite,
ferric oxide, and halite. Uranium deposits in calcrete are the largest of the surficial deposits. Uranium mineralisation
is in fine-grained surficial sand and clay, cemented by calcium and magnesium carbonates. Surficial uranium deposits
also occur in peat, bog, karst caverns and soils.
 Deposits of this type are found in United States, Australia, Canada and Namibia.
 Surficial deposits comprise approximately 4% of world uranium resources. Calcrete deposits represent 4% of
Australia's total reserves and resources of uranium. The Yeelirrie deposit in Western Australia is by far the world's
largest surficial deposit. Other significant deposits in Western Australia include Lake Way, Centipede, Thatcher Soak,
and Lake Maitland.
 In Western Australia, the calcrete uranium deposits occur in valley-fill sediments along Tertiary drainage channels,
and in playa lake sediments. These deposits overlie Archaean granite and greenstone basement of the northern
portion of the Yilgarn Craton. The uranium mineralisation is carnotite (hydrated potassium uranium vanadium
oxide).
 Calcrete uranium deposits also occur in the Central Namib Desert of Namibia.
23 November 2015 33
Granite-Pegmatite Hosted Uranium
West Central, Namibia
U Ore Deposits

 Deposits are associated with fault, fracture and shear zones in acidic
volcanic rocks.
 Uranium deposits of this type occur in acid volcanic rocks and are related to
faults and shear zones within the volcanics. Uranium is commonly
associated with molybdenum and fluorine.
 These deposits make up only a small proportion of the world's uranium
resources.
 Deposits of this type are found in China, Russia, Kazakhstan, Mexico,
Namibia, Greenland, South Africa, United States, Canada and Australia.
 Significant resources of this type occur in China, Kazakstan, Russian
Federation and Mexico.
 In Australia, volcanic deposits are quantitatively very minor - Ben Lomond
and Maureen are the most significant deposits.
23 November 2015 34
U Ore Deposits

8) Intrusive deposits
 Included in this type are those associated with intrusive rocks
including alaskite, granite, pegmatite, and monzonites.
 In intermediate to acidic igneous rocks and pegmatites, the uranium-
rich minerals are direct precipitates (no dissolution and
remobilization. Major world deposits include Rossing (Namibia),
Ilimaussaq (Greenland), USA, Canada, and Palabora (South Africa).
 In Australia, the only significant deposits are the large bodies of low
grade mineralisation at Crocker Well and Mount Victoria in the Olary
Province, South Africa.
23 November 2015 35
U Ore Deposits

 These occur in structurally-deformed rocks that were already altered by
metasomatic processes, usually associated with the introduction of
sodium, potassium or calcium into these rocks { i.e., Hydrothermal
alteration of deformed basement rocks}.
 Major examples of this type include Espinharas deposit (Brazil), Australia,
and the Zheltye Vody deposit (Ukraine).
 In Australia the largest of this type was Mary Kathleen uranium/rare earth
deposit, 60km east of Mount Isa, Qld, which was mined 1958-63 and 1976-
82. The orebody occurs in a zone of calcium-rich alteration within
Proterozoic metamorphic rocks.
23 November 2015 36
U Ore Deposits

10) Vein deposits
 Vein deposits constitute about 9% of world uranium resources.
 Not all Uranium veins are epithermal; the majority appear to form at higher Temperature (360 - 120°C)
and are therefore more appropriately considered hypo- or mesothermal…!
 Ore minerals: Uraninite or pitchblende, Uranothorianite, brannerite, coffinite, in addition to allanite,
sphene, monazite and zircon. These minerals are often associated with fluorite, hematite, pyrite,
calcite, quartz, galena and molybdenite.
 Host rocks: mostly two mica granites (S-type), but veins are also known to occur in I-type granites.
These host rocks are also considered the source of the metal.
 Geologic setting: In orogenic belts where anatexis took place leading to the formation of
peraluminous S-type granites.
 Origin: Epigenetic deposits formed by the leaching of U from the host granite by hydrothermal
solutions, and its deposition within the same bodies mainly in the form pitchblende.
 Major deposits include Jachymov (Czech Republic), Congo, Shinkolobwe (Zaire) and Radium Hill
(Southern Australia). The largest vein deposit in Australia was Radium Hill (Southern Australia) which
was mined from 1954-62. Mineralisation was mostly davidite.
 Deposits of this type are found in Australia, France, Czech Republic, Germany and Zaire.
23 November 2015 37
U Ore Deposits
Sunday-Uranium-Mine-Tour-veins-sm

11) Phosphorite and Lignite deposits
The uranium occurs with organic-rich marine-
deposited phosphorites (within the apatitie) or in
lignites (low-grade coal).
Fly ash, the result of burning coal, can increase the
U concentration by burning off the carbon.
Deposits of this type are found in the United States.
23 November 2015 38
U Ore Deposits

Uranium Resources
Identified (Reasonably Assured + Inferred) Resources
(in 1000 tonnes)
< US $ 40 / kgU < US $ 80 kgU < US $ 130 / kgU
World > 2746 3804 4743
Australia
Canada
Kazakhstan
Niger
Brazil
South Africa
Namibia
USA
Uzbekistan
Russia
701+343
287+85
279+130
173+0
140+0
89+55
62+61
NA
60+31
58+22
714+360
345+99
378+228
180+45
158+74
177+72
151+86
102+
60+31
132+41
747+396
345+99
514+302
180+45
158+121
256+85
183+100
342+
77+39
132+41
23 November 2015 39
U Ore Deposits

Production from mines (tonnes U)
Country 2003 2004 2005 2006 2007 2008 2009 2010
Kazakhstan 3300 3719 4357 5279 6637 8521 14020 17803
Canada 10457 11597 11628 9862 9476 9000 10173 9783
Australia 7572 8982 9516 7593 8611 8430 7982 5900
Namibia 2036 3038 3147 3067 2879 4366 4626 4496
Niger 3143 3282 3093 3434 3153 3032 3243 4198
Russia 3150 3200 3431 3262 3413 3521 3564 3562
Uzbekistan 1598 2016 2300 2260 2320 2338 2429 2400
USA 779 878 1039 1672 1654 1430 1453 1660
Ukraine (est) 800 800 800 800 846 800 840 850
China (est) 750 750 750 750 712 769 750 827
Malawi 104 670
South Africa 758 755 674 534 539 655 563 583
India (est) 230 230 230 177 270 271 290 400
Czech Repub. 452 412 408 359 306 263 258 254
Brazil 310 300 110 190 299 330 345 148
Romania (est) 90 90 90 90 77 77 75 77
Pakistan (est) 45 45 45 45 45 45 50 45
France 0 7 7 5 4 5 8 7
Germany 104 77 94 65 41 0 0 0
total world 35 574 40 178 41 719 39 444 41 282 43 853 50 772 53 663
tonnes U3O8 41 944 47 382 49 199 46 516 48 683 51 716 59 875 63 285
percentage of
world demand
65% 63% 64% 68% 78% 78%
World Nuclear Association Market Report data
23 November 2015 40
U Ore Deposits

Current Worldwide Uranium Production
• About 62 percent of the world's production of
uranium from mines is from Kazakhstan, Canada
and Australia.
• Kazakhstan produces the largest share of uranium
from mines (36% of world supply from mines),
followed by Canada (15%) and Australia (12%).
24 November 2015 41
U Ore Deposits

Primary Production - 2014
Uranium from Africa
• More than 15% of the world's mined uranium is
produced in Africa, and this percentage is expected
to increase in the future. As uranium mining is
associated with various negative externalities such
as environmental pollution and deterioration of
health, intensified uranium production in Africa can
lead to a wide variety of hazards. Preventing and
managing the multiple hazards is a complicated task
which requires specific knowledge, efforts, and
financial means available in all responsible
stakeholders. It can be questioned if all of these
factors are available in the African states which are
allowing uranium mining operations on their land.
24 November 2015
U Ore Deposits
42
http://www.wise-uranium.org/umaps.html?set=ures
Production vs. Consumption

Uranium Spot Prices: 1988-2010
23 November 2015
U Ore Deposits
43

 WNA expects 2011 production to be 56,050 tU. UxC predicts further
increase to about 63,600 tU in 2012.
 Mining methods have been changing.
 In 1990, 55% of world production came from underground mines, but this
shrunk dramatically to 1999, with 33% then. From 2000 the new
Canadian mines increased it again, and with Olympic Dam it is now one
third. In situ leach (ISL, or ISR) mining has been steadily increasing its
share of the total, mainly due to Kazakhstan.
 In 2010 production was as follows:
Method tonnes U %
Conventional underground 15,095 28%
Conventional open pit 13,541 25%
In situ leach (ISL) 22,108 41%
By-product 2920 5%
(considering Olympic Dam as by-product rather than in underground category)
23 November 2015 44
U Ore Deposits

In-situ Leaching

In-situ Leaching Uranium deposits
Uranium minerals are soluble in acidic or alkaline solutions.
The production (“pregnant”) fluid consisting of the water soluble uranyl
oxyanion (UO22+) is subject to further processing on surface to precipitate
the concentrated mineral product U3O8 or UO3(yellowcake).
23 November 2015 46
Acid leaching fluid
sulphuric acid + oxidant (nitric acid,
hydrogen peroxide or dissolved oxygen)
or
Alkali leaching fluid
ammonia, ammonium
carbonate/bicarbonate,
or sodium carbonate/bicarbonate
The hydrology of the acquifer is irreversibly
changed: its porosity, permeability and
water quality. It is regarded as being easier
to “restore” an acquifer after alkali
leaching. Figure from Hartman and Mutmansky, 2002.

Known Recoverable Resources* of Uranium 2007
tonnes U percentage of world
Australia 1,243,000 23%
Kazakhstan 817,000 15%
Russia 546,000 10%
South Africa 435,000 8%
Canada 423,000 8%
USA 342,000 6%
Brazil 278,000 5%
Namibia 275,000 5%
Niger 274,000 5%
Ukraine 200,000 4%
Jordan 112,000 2%
Uzbekistan 111,000 2%
India 73,000 1%
China 68,000 1%
Mongolia 62,000 1%
other 210,000 4%
World total 5,469,000
Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/07, from OECD NEA &
IAEA, Uranium 2007: Resources, Production and Demand ("Red Book").
Sources: World Nuclear Association
23 November 2015 47
U Ore Deposits

Good Uranium Deposits
• Shallow
• Open Pit or
• In-Situ Recovery
• SANDSTONE-HOSTED
• UNCONFORMITY-STYLE
• GRANITE-PEGMATITE HOSTED
GOOD U3O8 DEPOSITS

Uranium Fuel Cycle

Uranium Occurrence in the Egypt
 Most of these works were concentrated on the Eastern Desert terrains, particularly in granitic
rocks. Main discoveries are four uranium occurrences in Pan African younger granites, besides one
at the contact of bostonites and felsite dykes in metasediments and one in passamitic gneisses in
the Eastern Desert, as well as one in siltstone in a Paleozoic sedimentary basin within granitic rocks
in Sinai.
 Two new activities are now underway; namely: exploratory drilling programs at Atshan uranium
occurrences in the Eastern Desert and Sinai with newly acquired equipment, and experimental
heap leaching of the low grade uranium ores at Abu Zeinima in West Central Sinai.
 Exploration activities have been recently directed also to new target areas in sedimentary
formations and intracratonic sedimentary basins. The possibility of the occurrence of unconformity
related deposits are also considered.
 Western Desert: uranium in sedimentary host rocks of different ages (Carboniferous,
Oligocene) in Gabal Qatrani, Gabal Hafhuf (Bahariya Oases), as well as in sabkha.
 Eastern Desert: vein-type uranium associated with post-orogenic granitic magmatism of
Pan- African age at EI-Maghrabiya (El Erediya and El Missikat), Um Ara and Gabal Gattar.
 Sinai Peninsula: uranium mineralization in a karst environment in Carboniferous dolomites
at Abu Zeneima.
 The above occurrences have been investigated by surface methods, including topographic, geologic
and radiometric mapping, as well as by some trenching and tunneling.
51

Types of Uranium Deposits in Egypt
 Uranium mineralization is known in varied environments in Egypt. It is known in association with some Carboniferous and Cretaceous black shales, and in
phosphorite deposits. It was also discovered in the Oligocene sandstones and associated rocks at Gabal Qatrani, where uranium of up to 0.3% U3O8, is
concentrated in the intersitital spaces between sand grains (Said, 1962).
 Uranium - thorium exploration activity started in Egypt as early as 1956. These activities led to the discovery of several uranium anomalies and
occurrences, especially in the younger granites. In almost all of these occurrences, the U-mineralization is structurally controlled with preferable
development at the marginal zones of the enclosing granites or associated with wide scale alteration features. But, the question is why some Egyptian
younger granitic masses do not show any valuable U-anomalies, in spite of the presence of fracturing and large scale alteration.
 Thus, not only secondary processes (as fracturing or alteration) but also the magmatic processes may represent the main factors controlling U-
distribution. In other words, the composition of magma may introduce U-poor or U-rich granites. Alteration and fracturing of U-rich granites help
meteoric water and hydrothermal solutions to liberate labile uranium and precipitate their loads along microfractures, joints and fault planes.
 The uranium-bearing deposits of Egypt can be described as follows:
1) In black sands (in the northern coast from Rasheed to Rafah city).
2) In sabkha deposits (e.g., in Sitra, Nuweirnicya, Bahrein and El Arag lakes in the Western Desert).
3) In phosphate deposits (e.g., Abu Tartour, Hamarwain, Mahamid).
4) In shales and the carbonaceous sediments (e.g., Um Bogma, Um Kharit Qattrani, Bahariya oases)
5) In episyenites (e.g., Gabal Kab Ameri and Gabal Gattar).
6) In felsites (e.g., Atshan area, Wadi EI-Kareim).
7) In younger granites (e.g., Gattar, Missikat, El Erediya and Gabal Um Ara).
8) In siltstone of Hammamat deposits (e.g., Um Tawat, Wadi EI-Kareim).
 The Egyptian Shield rocks show very wide range due to lithologic variation, the younger granites show the highest radioactivity level followed by the
acidic volcanics but the other rock types display the lowest radioactivity levels.
 The distribution of uranium and thorium in the Egyptian Shield rocks, however, most of the attention is paid to the younger granites. It is thought that
younger granites could contribute more than the others and are abnormal. The uranium mineralization related to granite masses, where it occurs either
as disseminations in the autometasomatically altered parts (greisens and albitites), or where it forms veinlets and stringers across granite masses
(Hussein et al., 1986).
 Several plutons of these granites in the Eastern Desert, host a variety of rare metal mineralization including uranium. The Gattar granite pluton, at the
northern-part on the Eastern Desert, hosts vein-type uranium mineralization associated with molybdenite. Two younger granite plutons: namely El
Missikat and El Erediya (El Maghrabiya area), in the central part of the Eastern desert, host siliceous vein-type uranium mineralization, which is
structurally controlled by faults and their leather joints associated with NE and NNE trending shear zones. At the southern part of the Eastern Desert, Um
Ara granite hosts uranium as disseminated unconformity contact type. The estimation of the uranium potentiality of the four younger granite plutons is
14000 tons uranium as speculative resources.

Main Occurrences
In the following some lights will be given to the areas with more potentialities in Egypt.
 Gabal Gattar area, at the northern-part on the Eastern Desert, is bounded by the following coordinates: longitudes
33° 13/ 26// - 33° 25/ 47// E and latitudes 27° 02/ 00// - 27° 08/ 30// N. Gabal Gattar area, as a segment of the north
Eastern Desert of Egypt, is a part of the Arabian-Nubian shield. This area is dominantly covered with basement
rocks, mainly younger granites of late Proterozoic age.
 The Gattar granite pluton hosts vein-type uranium mineralization associated with molybdenite. The younger
granites of Gabal Gattar acquire their importance from hosting of uranium mineralization in eight uraniferous
occurrences namely G-l, G-ll to G-VIII. They are characterized by visible intense secondary U-minerals with their
characteristic yellow to greenish yellow colours. Only one occurrences (G-V) was confined to a strongly altered
contact zone between the northern border of Gabal Gattar granite and the closely adjacent Hammamat sediments
of Gabal Um Tawat along Wadi Bali. The locations and distributions of the recorded uraniferous sectors are
structurally controlled by the NNE, NS and ENE major fracture systems and shear zones.
 The Gattarian granite mass forms an elongated huge granite batholith trending by its long dimension (40 km) in a
NS direction. More than 80 publications and internal reports had been carried out on this granite mass. The early
studies which had been carried out before 1984 were mainly dealt with the geology, petrography, geochronology
and geochemistry of the normal Gattarian granites as well as the mining prospection for molybdenum deposit.
After discovering U-mineralization in Gabal Gattar granites (northern part of the Gattarian granite batholith) by
NMA during the field season 1984/1985. The pluton became an important target for various detailed field and
laboratory studies. Moreover, underground drilling and mining exploration aspects have been carried out on the
aim of developing the more promising U-occurrences recorded as well as to follow up U mineralization at deeper
levels.
 Structurally, The Gattarian granite batholith was subjected to more than one tectonic episode printed on the rock
surfaces, by joints, faults and shear zones of various attitudes and directions. The NNE, NS, NE and ENE directions
represent the most significant fracture systems and shear zones. Along these fractures, granites are highly sheared
and extensively subjected to various deuteric and post magmatic hydrothermal alterations. Hematitization
silicification, kaolinization and epidotization are the most pronounced alteration features encountered
Fluoritization, episyenitization and carbonatization are superimposed later. Among these alteration features, the
hematitization, episyenitization of the granites and fluoritization are the most significant ones, since they are
oftenly associated with most of the recorded U-mineralized sectors.

Geologic map
showing intra-
mountain basin,
NED, Egypt

 Nearly all the recorded U-mineralized sectors are found to be associated with strongly deformed and deeply hematitized
granite zones. Only one occurrence (G-V) was confined to a strongly altered contact zone between the northern border of
Gabal Gattar granite and the closely adjacent Hammamat sediments of Gabal Um Tawat along W. Bali. The locations and
distributions of the recorded uraniferous major fracture systems sectors are structurally controlled and shear zones.
 G-l, G-II, G-V and G-VI represent the most significant and more promising uraniferous occurrences. The visible secondary
U-minerals are encountered filling large and feather fractures with thickness ranging from a few mm to a~8 mm. They are
always accompanied with deep brown hematite and occasionally with dark violet fluorite.
 Radiometrically, the normal granites forming Gabal Gattar are considered as an uraniferous granite type, its specific
background gamma activity range is normally exceeding than that of the normal world granites (4 ppm U and 14 ppm Th).
It has U-contents ranging from 12 to 30 ppm with an average value of 18 ppm, whereas their Th-contents are within the
normal value (15 ppm).
 U and Th are concentrated mainly in the accessory minerals; more than 80 % of U is contained in accessory minerals while
only a maximum of 20 % U is associated with essential minerals. The secondary minerals (as hematite, fluorite and clay
minerals), which formed during post magmatic processes, concentrate much more U than Th indicating that U enrichment
is controlled mainly by post magmatic processes to a great extent.
 The main U-minerals in Gabal Gattar U-prospect identified are given below. These U-minerals are occasionally associated
with calcite, fluorite, hematite, and ilmenite. Biotite, zircon, wolfenite, and chlorite. Some of these gangue minerals,
especially hematite and ilmenite, play an important role in fixation of U-minerals from its beating circulating water.
Minerals Formulae
Uraninite 2UO2
Carnotite K2O, 2UO2, 2VO4
Umohoite UO2, MoO4, 4H2O
BeCquerelite 7UO3, H2O
Masuyite UO3. H2O
Uranophane CaO, 2UO2 , 2SiO2, 6H2O
-Uranophane CaO, 2UO2, 2SiO2. 6H2O
Kasolite Pb, 2UO2, 2SiO2, 2H2O
Zippeite 2UO3, 2SiO2. 2H2O
Soddyite 3UO2, 2SiO4, OH, 5H2O
The encountered U-minerals are usually associated with dark
brown hematite and occasionally with deep violet fluorite. The
latter is sometimes recorded without my trace of U-minerals
indicating presence of two generations of fluorite. Primary U-
minerals (uraninite) are occasionally identified in some
intensely uraniferous parts.

Origin of uranium mineralization in Gabal Gattar:-
 Uranium mineralization in Gabal Gattar uranium prospect could be controlling by the following factors (Shalaby, 1990):-
1) Mineralogical composition of the host granites.
2) High magmatic uranium background.
3) Presence of adequate structures which facilitate the circulation of hydrothermal-fluids.
 Moreover, the highest U and Th contents are displayed by hematitized granite. This feature supports the hydrothermal concept of mineralization at Gabal Gattar uranium prospect. The
probable source of uranium bearing fluids could originate be either from the granite at its late or post magmatic stage or from some deeper source (Roz, 1994).
 On the other hand, the hypogene enrichment in uranium in the G-l occurrence is mostly due to hydrothermal solutions rich with uranium which affected the Gattar granite and resulted in
their intense alteration and deposited their uranium in the structural network of the rocks. A supergene source of enrichment in uranium is mainly due to the leaching of some of the
magmatic uranium from the host rocks by meteoric fluids that were drained to the fractured and sheared zones, where they deposited their loads (Moharem, 1997).
 Gattar granite was affected by strong acidic changed later to strong alkaline hydrothermal solutions. These solutions played the most important role in the alteration of Gattar granite
along shear zones. Acidic solutions with low U, Th and Zr contents resulted in kaolinization of Gattar granite along shear zone. The acidic solutions were changed to alkaline solutions
rich in Fe, Th and U. In hematitized granite, U and Th replaced Zr especially along zircon rims while iron oxides adsorbed most U and precipitated along fractures or coated the
metamicted zircon crystals (Dardier, 2000).
 Thus, a positive correlation between the degree of hematitization and the intensity of uranium mineralization. The presence of quartz veinlets and deep violet fluorite in the mineralized
granites is a supporting evidence for hydrothermal vein type uranium mineralization (Salman et al., 1990 and Shalaby, 1995).
 Shalaby and Moharem (2001) suggested that the geochemical behavior of U and the genesis of U deposits in the G-V occurrence could have proceeded through the following
successive stages:
(1) Uranium was first mainly trapped in the crystal lattice of accessory minerals of the granites.
(2) The area was affected by tectonic events producing faults and shear zones which acted as good channels for the hydrothermal ascending fluids and the percolating meteoric
water to mix with the trapped residual magmatic fluids rich in U and Th, and generating a low temperature hydrothermal system. This released U from the essential and accessory
minerals of the hosting granites and redeposited it as uranium minerals in the shear zones. , and
(3) The supergene meteoric water and super-heated solutions could pass through the structural network. They leached some of the magmatic U from the younger granites and
reprecipitated their loads, in the shear and weak zones of the Hammamat sediments, by the effect of evaporation and adsorption on the surface of Fe oxides and clay minerals.
 The hydrothermal concept could be accepted for the local uranium mineralizations in the shear zone, but the surfacial enrichment of secondary uranium could, however, be considered
as due to the oxidation and mobilization of uranium and the adsorption of its minerals on the surface of clay minerals and iron oxides in granites.
 Therefore, magmatic differentiation plays a small part in uranium enrichment but secondary processes played the principal role in the uranium enrichment of the mineralized granites, as
following:
1)The fresh granite of Gabal Gattar could be classified as uraniferous granites. They are highly affected by faulting, jointing and fracturing due to the active role of the various
tectonic movements.
2)The planes of such structure provided easy channels for the passage of solutions.
3)These solutions affected the granites and resulted in their intense alteration. The types of alteration processes affect the uranium concentration and its redistribution.
4)The U-bearing solutions may be of hypogene origin and ascending through the structural network of fractures, and joints which form suitable structural traps for mineralization.,
5)The secondary source of uranium enrichment is the supergene fluids which percolate on the granite, and could leach some of their magmatic uranium.
6)The role of iron oxides in adsorbing uranium from its circulating solutions could not be neglected, and
7)The ascending alkaline hydrothermal solutions which caused hematitization are responsible for the U-mineralization along shear zones of Gattar pluton. Thus, U-concentrations
must probably increase with depth and the future subsurface works may explore primary U-mineralizations of economic potentialities.

2) Uranium deposits of Um Ara area
 Um Ara area bounded between latitudes 22° 30/and 22° 42/ N and longitude 33° 45/ and 33° 55/ E. The younger granitic pluton covers 30 km2 in the central
part. It is intruded into a tectonic mélange to the southeast, south and west. The mélange comprises metasedimentary matrix with the serpentinites making
up the rock fragments and blocks. The younger granites are faulted against the arc metavolcanics to the northern and faulted against the younger Dokhan
volcanics to the north.
 Um Ara granitic pluton was affected by faults having various trends. The major faults trend in the E-W, N-S, ENE, ESE, NE and NW directions. The earlier E-W
faults are sinistral faults with oblique slip. The N-S and ENE trending faults form conjugate set indicating crustal shortening in NE direction and extension in the
NW one. The later NW-faults are analogous to the NW-wrench faults of the Najd Fault System in Saudi Arabia and described in the Central Eastern Desert of
Egypt by Stem (1985).
• Um Ara granite pluton comprises three main rock varieties:
• a) Coarse grained monzogranitic phase covering about 90% of the pluton area.
• b) Fine grained alkali feldspar granitic phase covering the northern western corner. The fine-grained phase is intruded into earlier monzogranites and
exhibits the effects of intense mechanical deformation and shearing.
• c) Upper zinnwaldite albitized granite zone. The rock is fine grained, alkali feldspar granites and showing different of red, pink, buff, green and yellow
colours. They are essentially composed of quartz, K-feldspars and plagioclases. Biotite, phlogopite, muscovite and lepidolite are the main varieties. In
most cases, the micas are of secondary origin where they fill mariolitic vugs replacing the felsic components. The accessory minerals are mainly fluorite,
zircon, garnet and secondary uranium minerals.
 U-mineralization is dominated by uranophane and -uranophane (Fig. 7) and traces of Uraninite, topaz, monazite, zircon, apatite, rutile and fluorite. The
association of topaz and monazite with Li-rich mica indicates the enrichment of the late stage hydrothermal fluids in F and P (London, 1987).
• The U and Th contents of the fresh granites of Um Ara can be classified into:
low U (<16 ppm) low Th (<27 ppm) with Th/U ratios (1.4-2.2) and
high U (16-23 ppm) high Th (42-75 ppm) with Tb/U ratios (1.8-2.4).
 The U against Th/U ratios relationship shows a steep decreasing trend. They also suggest that most of the U is located in Th-rich accessory minerals such as
monazite and that the labile U is preferentially leached and adsorbed on the Fe-oxides until reacted later from secondary U-minerals by hydrothermal fluids.
• The hydrothermally altered or mineralized granites can be categorized into 3 groups according to their U and Th contents as follows:
low U (<100 ppm)-low Th (<60 ppm),
moderate U (100-300 ppm)-low Th (9-7 1 ppm), and
high U (>300 ppm)-moderate to high (56-455 ppm).
 The high variations of U-contents indicate the high mobility of U during the hydrothermal stage and concentration of U under highly oxidizing conditions. The
much higher mobility of U compared to Th indicates that the hydrothermal fluids were also enriched in Cl- which capable of mobilizing U only but not Th
(Keppler and Wyllie, 1990).
23 November 2015 57
U Ore Deposits

Regional
geologic map
for Wadi El
Kareem Area,
ED, Egypt

References
Mostly condensed from:
•Lambert,I., McKay, A., and Miezitis, Y. (1996) Australia's uranium resources: trends,
global comparisons and new developments, Bureau of Resource Sciences, Canberra,
with their earlier paper: Overview of Australian and World Uranium Resources, ANA
Conference Nov 1995.
•Minerals from: Aust IMM, Field Geologist's Manual, 1989.
For additional information on uranium deposits go to
•International Atomic Energy Agency (IAEA)
•World Nuclear Association.
•Uranium Minerals
•Uranium Deposits
•World Nuclear Assoc. - Geology of Uranium
•Australia Uranium Association
•Natural Resource Canada - Athabasca Uranium
•Uranium in New Mexico
•Wikipedia - Uranium
•World Nuclear Assoc. - Mining links
•Wise Uranium Project - Maps
•World Nuclear Assoc. - Production Figures
•Wyoming Geological Survey

Uranium Ore Deposits

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