TYPES OF URANIUM DEPOSITS

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TYPES OF URANIUM DEPOSITS
Virginia T. McLemore New Mexico Bureau of Geology
and Mineral Resources New Mexico Institute of
Mining and Technology, Socorro, NM
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Outline

• How do we classify mineral deposits?
• Formation of uranium deposits
• Parameters
• Types of deposits
• What are the major types in North America

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HOW DO WE CLASSIFY MINERAL DEPOSITS?
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HOW DO WE CLASSIFY MINERAL DEPOSITS?

• Tectonics
• Mineralogy
• Chemistry
• Host rock
• Commodity
• Form
• Mining method
• Orogenesis

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Foramtion of uranium deposits

• ore-element source
• mineralizing fluid source
• mobilization mechanism
• migration mechanism and form
• regional migration control
• local migration control

• internal environment (fluid character)
• at deposition site
• external environment (rock character) at
  deposition site
• concentration mechanism
• fixation mechanism
• preservation

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What important parameters to characterize uranium
deposits?

• location
• shape
• size
• depth
• orientation
• geotectonics
• mineralogy
• hydrology
• boundary conditions

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TYPES OF DEPOSITS

• Unconformity-related deposits
• Sandstone deposits
• Quartz-pebble conglomerate deposits
• Vein deposits
• Breccia complex deposits
• Intrusive deposits
• Phosphorite deposits

• Collapse breccia pipe deposits
• Volcanic deposits
• Surficial deposits
• Metasomatite deposits
• Metamorphic deposits
• Lignite
• Black shale deposits
• Other types of deposits

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Hitzman and Valenta, 2005, Economic Geology, v.
100, pp. 16571661
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Unconformity-associated uranium deposits
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Types of Unconformity-associated uranium deposits

• Clay-bound Proterozoic unconformity
• Strata-bound Proterozoic unconformity
• Strata-bound proterozoic unconformity
• Phanerozoic unconformity-related

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Unconformity-associated uranium deposits

• Massive pods, veins and/or disseminated uraninite
  associated with unconformities between
  Proterozoic siliciclastic red beds and
  metamorphic basement that includes graphitic
  metapelite and radiogenic granite.

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Unconformity-associated uranium deposits

• Pitchblende fills extensional features in
  reactivated fault zones and replaces matrix in
  sandstone
• One mining district in Canada the Athabasca
  Basin- gt30 deposits /prospects - most in
  eastern ¼ of basin- produces 1/3 of worlds U

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World Unconformity-associated U Deposits
590 Economic / potential U deposits all types
gt500 Tonnes U _at_ gt0.03 U (IAEA)
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Distribution and value of Unconformity U
deposits in Canada
CommoditiesU gtgt Ni gtgtAu,Cu,PGE Resources,
Athabasca Basin (A) 553,778 Tonnes U _at_ 1.922
U (average) Up to 25 U (P2) 30,237,488,300 (30
billion)18 deposits mined, all in
SaskatchewanCigar Lake (2007) Cluff Lake (7),
Collins Bay (3), Eagle Pt., Key Lake (2) McArthur
R (P2), McClean Lake (2), Rabbit Lake
E
H
T
A
Hw
O
S
C
Prospective basins
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One deposit type, two end-member fluid flows
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One deposit type, two extremes of alteration
Quartz dissolution, e.g. Cigar Lake
Early silicification, e.g. McArthur River
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Temporal Distribution of U Deposits
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Summary Unconformity-associated U Deposit
Empirical Geological Model
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Key Exploration Criteria for Unconformity-Associa
ted Uranium Deposits

• Tectonic settings Intra-cratonic late
  collisional far-field stresses

• Basin Repeated fault reactivation,
  paleo-valleys, hills
• Architecture Fluvial systems, 1780-1540 Ma,
  sources lt150 km

• Geophysics EM - graphitic basement metapelite
  need deep systems
• AMT new deep conductors,
  resistivity maps alteration
• Seismic maps unconformity and
  intersecting structures

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Key Exploration Criteria for Unconformity-Associa
ted Uranium Deposits

• Paleo-Environment Warm humid, intense
  weathering, red regolith

• Geology Drilling, structural models faults,
  intersections

• Modeling 1st hydrothermal fluids 1670, 2nd
  1450 Ma, remobilized
• Hydrocarbons and pyrobitumens
  post-U (controversy).

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Major unconformity type deposits in the world

• Athabasca Basin, Saskatchewan, Canada
• Pine Creek Geosyncline, Northern Territory,
  Australia

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SANDSTONE
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(No Transcript)
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Quartz-pebble conglomerate deposits
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Quartz-pebble conglomerate deposits

• Upper Archean to Lower Proterozoic age
• consist of detrital ore minerals of uranium and
  other metals
• pyrite
• Interbedded within siliciclastic sequences
  containing layers of quartzite and argillite
• mineralized conglomerates.
• Blind River, uranium and rare earth elements base
  of the stratigraphic sequence above the
  unconformity.
• In the Witwatersrand, uranium in multiple beds
  dispersed through a thick stratigraphic sequence
  and is recovered as a by-product of gold
  production.

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Quartz-pebble conglomerate deposits

• Blind River Elliot Lake, Ontario, Canada
• Witwatersrand, South Africa

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Veins
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Veins

• lenses or sheets in joints, fractures, breccias
  or stockworks.
• pitchblende and/or coffinite
• Size veins varies
• spatially related to granite
• transect metamorphic or sedimentary rocks
• Breccia complex uranium deposits

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Breccia complex depositsIron oxide-copper-gold
(IOCG) deposits
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Breccia complex depositsIron oxide-copper-gold
(IOCG) deposits

• Olympic Dam deposit
• hematite-rich granite breccia
• iron, copper, uranium, gold, silver, rare earth
  elements (mainly lanthanum and cerium) and
  fluorine
• hydraulic fracturing, tectonic faulting, chemical
  corrosion, and gravity collapse

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Hitzman and Valenta, 2005, Economic Geology, v.
100, pp. 16571661
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Olympic Dam deposit in Australia

• Measured resource of 650 million tons (Mt) of 500
  g/t U3O8 (425 ppm U), 1.5 percent Cu, and 0.5 g/t
  Au
• Total resource approximately 3.8 billion tons of
  400 g/t U3O8 (339 ppm U), 1.1 percent Cu, and 0.5
  g/t Au.

Hitzman and Valenta, 2005, Economic Geology, v.
100, pp. 16571661
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Barton et al, 2000
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Surficial deposits
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Surficial deposits

• young (Tertiary to Recent) near-surface uranium
  concentrations in sediments or soils
• secondary cementing minerals including calcite,
  gypsum, dolomite, ferric oxide, and halite
• uranyl minerals or adsorbed on other materials

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Calcrete deposits

• uranium-rich granites were deeply weathered in a
  semi-arid to arid climate
• valley-fill sediments along Tertiary drainage
  channels, and in playa lake sediments
• Lake Raeside, Australia

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Volcanic deposits
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Volcanic deposits

• acid volcanic rocks and are related to faults and
  shear zones within the volcanics
• commonly associated with molybdenum and fluorine

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Lakeview U District
225 t U3O8 production (1960s) unknown resource
remains Now an EPA Superfund site Withdrawn
from mining til 2013
Lucky Lass Mine
White King open pit
White King Mine
Dump samples as much as 0.3 U3O8 1.8 Pb 1 As
0.4 Hg also elevated Cs, Mo, Sb
Steve Castor, 2007
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Basalt flows
1 cm
1.3 U3O8
Debris flows
U Silico- phosphate
Peraluminous flow-banded rhyolite
Breccia ore
Volcanic sediment
Clay alteration
Galena
Steve Castor, 2007
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Uranium Mineralogy
Autunite filled fractures within volcanic
ignimbrites, Macusani Peru.
(Solex Resources Corp.)
(Strathmore Minerals Corp.)
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Intrusive deposits
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Intrusive deposits

• Alaskite
• Rössing, Namibia
• Granite, Monzonite
• Bingham Canyon, Utah, USA
• Pegmatite
• Bancroft area, Ontario, Canada
• Peralkaline syenite
• Kvanefjeld, Greenland
• Carbonatites
• Phalaborwa, South Africa

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Phosphorite
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Phosphorite

• fine-grained apatite in phosphorite horizons
  within interbedded marine muds, shales,
  carbonates and sandstones
• primary bedded (Phosphoria Formation, UtahIdaho)
• sedimentologically reworked (Florida) phosphorite

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Collapse breccia pipe
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Collapse breccia pipe

• Circular, vertical (up to 1000 metres in vertical
  extent) pipes filled with down-dropped coarse and
  fine fragments stopped from the overlying
  sediments
• Mineralized pipes range from 30 to 200 metres in
  diameter
• Orphan mine, Arizona, USA

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What are the major uranium deposit types in North
America?
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Major Uranium Deposit Types North America

• Unconformity
• Athabasca Basin, Saskatchewan and Thelon Basin,
  NWT
• Sandstone
• Intermountain basins of Wyoming Colorado
  Plateau Gulf Coast Plain of Texas Grants
  Mineral Belt, New Mexico
• Breccia Pipes
• Northern Arizona
• Quartz-pebble conglomerate
• Elliot Lake