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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
Outline
• How do we classify mineral deposits?
• Formation of uranium deposits• Parameters • Types of deposits• What are the major types in North
America
HOW DO WE CLASSIFY MINERAL DEPOSITS?• Tectonics• Mineralogy• Chemistry• Host rock• Commodity• Form• Mining method• Orogenesis
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
What important parameters to characterize uranium deposits?• location• shape• size• depth• orientation• geotectonics• mineralogy• hydrology• boundary conditions
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
Types of Unconformity-Types of Unconformity-associated associated uranium depositsuranium deposits
• Clay-bound Proterozoic unconformity
• Strata-bound Proterozoic unconformity
• Strata-bound proterozoic unconformity
• Phanerozoic unconformity-related
Unconformity-associated Unconformity-associated uranium depositsuranium depositsUnconformity-associated Unconformity-associated uranium depositsuranium 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.
Unconformity-associated Unconformity-associated uranium depositsuranium depositsUnconformity-associated Unconformity-associated uranium depositsuranium deposits
• Pitchblende fills extensional features in reactivated fault zones and replaces matrix in sandstone
• One mining district in Canada – the Athabasca Basin- >30 deposits /prospects - most in eastern ¼ of basin- produces 1/3 of world’s U
World Unconformity-associated U DepositsWorld Unconformity-associated U Deposits
590 Economic / potential U deposits all types >500 Tonnes U @ >0.03% U (IAEA)
Distribution and value Distribution and value of Unconformity U of Unconformity U deposits in Canadadeposits in Canada
Distribution and value Distribution and value of Unconformity U of Unconformity U deposits in Canadadeposits in Canada
CommoditiesU >> Ni >>Au,Cu,PGE
Resources, Athabasca Basin (A): 553,778 Tonnes U@ 1.922 % U (average)Up to 25% U (P2)$30,237,488,300($30 billion)
18 deposits mined, all in Saskatchewan:Cigar Lake (~2007)Cluff Lake (7), Collins Bay (3), Eagle Pt., Key Lake (2)McArthur R (P2), McClean Lake (2), Rabbit LakeProspective basins
AT
H
OS
Hw
C
E
One deposit type, two extremes of alterationOne deposit type, two extremes of alteration
Quartz dissolution, e.g. Cigar Lake
Early silicification, e.g. McArthur River
Summary: Summary: Unconformity-associated U Deposit Unconformity-associated U Deposit
Empirical Geological ModelEmpirical Geological Model
Summary: Summary: Unconformity-associated U Deposit Unconformity-associated U Deposit
Empirical Geological ModelEmpirical Geological Model
AthabascaGroup
Quaternary
regolith
GrowGrowfaulfaultstsalteratioalterationn
~ 100 m
W E
> 1750 Ma intercalated ortho- and paragneiss
unconformity
old old valleyvalley
grogrowwhilhilll
Mono-Mono-metallicmetallic
-basement hosted-basement hosted-uranium-uranium-Lower total REE-Lower total REE
Poly-Poly-metallimetalli
cc
-”sandstone” -”sandstone” hostedhosted-U, Ni, Co, Cu, As-U, Ni, Co, Cu, As-high total REE-high total REE
Key Exploration Criteria for Unconformity-Associated Uranium Deposits
Key Exploration Criteria for Unconformity-Associated Uranium Deposits
Geophysics: EM - graphitic basement metapelite; need deep systems AMT new deep conductors, resistivity maps alteration Seismic maps unconformity and intersecting structures
Tectonic settings: Intra-cratonic; late collisional far-field stresses
Basin Repeated fault reactivation, paleo-valleys, hills Architecture: Fluvial systems, 1780-1540 Ma, sources <150 km
Key Exploration Criteria for Unconformity-Associated Uranium Deposits
Key Exploration Criteria for Unconformity-Associated Uranium Deposits
Modeling: 1st hydrothermal fluids 1670, 2nd 1450 Ma, remobilized Hydrocarbons and pyrobitumens post-U (controversy).
Paleo-Environment: Warm & humid, intense weathering, red regolith
Geology: Drilling, structural models: faults, intersections
Major unconformity type deposits in the world
• Athabasca Basin, Saskatchewan, Canada
• Pine Creek Geosyncline, Northern Territory, Australia
Positive area
J
KG
G
E
D
B
NM
L
I
O
P
H
Positive areas: A = Black Hills; B = Bighorn Mts., C = Owl Creek Mts, D = Wind River Range, E = Rock Springs Uplift, F = Laramie Mts., G = Front Range, H = Uinta Range, I = Sa Rafael Swell, J = Uncompaghre Up-warp, K = San Juan Mts., L = Kaibab Up-warp, M = Circle Cliffs Up-warp, N = Monument Up-warp, O = Defiance Upwarp, P = Zuni Up-warp.
Area of volcanic activity
BighornBasin
Bridger and GreenRiver basins
Uinta and GreenRiver basins
Black Mesabasin
San Juanbasin
SouthPark
basin
PowderRiverBasin
Dominantly continental sedimentation
Postulated sediment transport
Dominantly lacustrine sedimentation
9
4
10
7 6
3
Basins: 3 = Wind River, 4 = Shirley, 6 = Hanna, 7 = Washakie, 9 = North Park, 10 = Green River.
Uranium deposits
2 0 0 k m
Context of Uranium deposits in Eocene sandstone
of Western USA (after Everhart (1985) and Finch (1967).
Highland Mountains
C A N A D A
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.
Quartz-pebble conglomerate deposits
• Blind River — Elliot Lake, Ontario, Canada
• Witwatersrand, South Africa
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
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
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, Hitzman and Valenta, 2005, Economic Geology, v. 100, pp. 1657–1661
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
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
Volcanic deposits
• acid volcanic rocks and are related to faults and shear zones within the volcanics
• commonly associated with molybdenum and fluorine
Lakeview U District
Lucky Lass Mine
White King Mine
White King open pit
225 t U3O8 production (1960s) unknown resource remains
Now an EPA Superfund site Withdrawn from mining til 2013
Dump samples as much as 0.3% U3O8 1.8% Pb
1% As 0.4% Hg
also elevated Cs, Mo, & SbSteve Castor, 2007
1 cm
Peraluminous flow-banded
rhyolite
Basalt flows
Debrisflows
Galena
U Silico-phosphate
BrecciaoreVolcanic
sediment Clayalteration
1.3% U3O8
Steve Castor, 2007
Autunite filled fractures within volcanic ignimbrites, Macusani Peru.
(Solex Resources Corp.)
Uranium Mineralogy
(Strathmore Minerals Corp.)
Intrusive deposits • Alaskite
• Rössing, Namibia• Granite, Monzonite
• Bingham Canyon, Utah, USA• Pegmatite
• Bancroft area, Ontario, Canada• Peralkaline syenite
• Kvanefjeld, Greenland• Carbonatites
• Phalaborwa, South Africa
Phosphorite
• fine-grained apatite in phosphorite horizons within interbedded marine muds, shales, carbonates and sandstones
• primary bedded (Phosphoria Formation, Utah–Idaho)
• sedimentologically reworked (Florida) phosphorite
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
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