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?

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

Hitzman and Hitzman and Valenta, 2005, Valenta, 2005, Economic Geology, v. 100, pp. 1657–1661

Unconformity-associated Unconformity-associated uranium depositsuranium 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 end-member fluid flows

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

Temporal Distribution of U DepositsTemporal Distribution of U Deposits

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

SANDSTONE

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

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

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

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

Hitzman and Valenta, 2005, Economic Geology, v. 100, pp. 1657–1661

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

Barton et al, 2000

Surficial deposits

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

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

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

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

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

What are the major uranium deposit types in North America?

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