EXTECH IV ATHABASCA URANIUM DEPOSIT DATABASE
Geological Survey of Canada, Saskatchewan Industry and Resources, and Alberta Geological Survey


DEPNO COUNTRY LOCATION ALLNAMES COMMODITIES
40023 Canada (Saskatchewan) 57.37.30 N -- 105.37.32 W Millennium Deposit; Millennium Prospect; Millennium Zone; Cree Lake Extension Project U

Database name: Uranium Deposits, Athabasca Basin
Custodial agency: Geological Survey of Canada
Compilers: Sunil S. Gandhi
Release date: 2007-03-02
   
Deposit name(s): Millennium Deposit (occurrence name); Millennium Prospect (occurrence name); Millennium Zone (occurrence name); Cree Lake Extension Project (claim name)
Political location(s): Canada; Province or state: Saskatchewan; Nearest community: McArthur River mine-mill complex (35 km SW)
NTS map data: 074H12 (Friesen Lake)
Deposit clan (type): Unconformity-associated
Deposit (sub) types: Unconformity-associated - Proterozoic - strata-bound; Mineralized lenses occur in paraneisses 150 m depth below the Athabasca unconformity, in the hanging wall of a thrust of the paragneisses over granitoid gneisses, and below a graphitic marker unit.; Reference: Roy, C.; Halaburda, J.; Thomas, D.; Hirsekorn, D., 2005: Millennium Deposit - Basement-hosted Derivative of the Unconformity Uranium Model; Topic: Uranium Geology & Deposits, In Symposium on Uranium Production and Raw Materials for Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security (IAEA-CN-128): Extended Synopses, Edited by Anonymous, International Atomic Energy Agency Conference (International Symposium), IAEA in co-operation with OECD/NEA, WNA, NEI and UN-ECE, International Atomic Energy Agency, CN-128, 344 p., p. 42 - 45
Deposit status: advanced prospect; Size category: large
Geologic province: Churchill - Hearne Craton
Geologic subprovince: Mudjatik Domain
Geologic district: Southeastern Athabasca Basin
Deposit object located: drill hole
Commodities: U
Mineralization styles: massive (mineralization zone); breccia - matrix (mineralization zone); fracture fill (mineralization zone); aggregates (mineralization zone); veinlets (mineralization zone)
Geological ages: Middle Mesoproterozoic - Late Mesoproterozoic (mineralization)
Late Paleoproterozoic (host rocks)
Late Paleoproterozoic - Middle Mesoproterozoic (country rocks)
Tectonic setting: continental marginal platform-fold belt; convergent; Formal name: Wollaston Fold Belt (host rocks)
Coincident features: strata-bound (a highly graphitic, east-dipping marker unit appears to control high grade mineralized zone on the footwall side, and a lower grade zone farther below); Coincident feature name: Pelitic gneiss
fault zone (a post-Athabasca Group reverse fault dipping about 60° to the east at the base of metasedimentary belt acted as channel way for mineralizing solutions); Coincident feature name: Millennium Fault (?)
Regional tectonic structure: thrust fault (post-Athabasca Group reverse fault at the base of the east-dipping host metasedimentary belt beneath the mineralized zones is concordant to the belt) Tectonic structure name: Millennium Fault (?)
fault (a major brecciated zone along the fault shows kinematic indicators for the reverse movement; it provided ingress of the mineralizing basinal fluids) Tectonic structure name: fault breccia zone
Host rocks: (1) metamorphic; metasedimentary schist (mineralization in two distinctive pelitic to semipelitic assembalges separated by a calc-silicate unit); Depositional setting: epizonal; Metamorphic grade: amphibolite; Component: basement mineralization
External host rock forms:tabular sedimentary body
Internal host rock structures:foliated
Individual lithologies:metapelite (pelite to semipelite; in part graphitic)
semipelite
Host rock stratigraphy:Wollaston Supergroup, Basal unit of Wollaston Supergroup Formation
Country rocks: (1) metasediments; (200 m thick zone of calc-silicates and metapelites with graphitic beds); Country rock name: Wollaston Group; Metamorphic grade: amphibolite
Country rock protoliths:siltstone-shale (calcareous and carbonaceous siltstone and shale beds regarded as part of basal Wollaston Group); Country rock protolith name: Wollaston Group
Individual lithologies:calc-silicate and graphitic shale (interbedded calc-silicates and meta-pelites; the latter include highly graphitic beds)

(2) granite; (granitic assemblage on both sides of metasedimentary rocks); Country rock name: reactivated Archean granitic complex; Metamorphic grade: amphibolite
Country rock protoliths:granite-granodiorite (granite to granodiorite pluton(s) in the Archean basement of the Wollaston Group remobilized during the Hudsonian orogeny); Country rock protolith name: Archean Basement Complex
Individual lithologies:granite-granodiorite-monzonite (equigranular to porphyritic granitoid rocks)

(3) granitoid; (pegmatite); Country rock name: Hudsonian Granites; Metamorphic grade: unknown
Country rock protoliths:granite (a concordant pegmatite sheet or zone upto 15 m thick, along the graphitic gneiss marker unit in the metasedimentary belt); Country rock protolith name: Pegmatite
Individual lithologies:pegmatite (coarse grained quartzo-feldspathic rock)

(4) sandstone; (600 m thick, flat-lying strata unconformably overlying crystalline basement); Country rock name: Athabasca Group; Metamorphic grade: unmetamorphosed
Country rock protoliths:arenite (essentially undeformed sediments except for some reverse faulting involving the basement); Country rock protolith name: Manitou Falls Formation
Individual lithologies:conglomerate-sandstone (mainly sandstones and pebbly sandstones with some conglomerate and siltstone beds)
Metallogenic signatures: U
Alteration signatures: argillic alteration: illite, dominant in and around high grade ore; What was altered: host metapeltic strata; Component: alteration halo
tourmalinization: dravitization in and around high grade ore; What was altered: host metapeltic strata; Component: alteration halo
chlorite alteration: chloritization in the proximal zone; What was altered: host metapeltic strata; Component: alteration halo
saussuritization: feldspar alteration in distal zone; What was altered: host metapelitic rocks; Component: alteration halo
Mineralogy: (alteration - undifferentiated / mineralization zone): sericite, chlorite, dravite, hematite
(alteration - undifferentiated / alteration halo): illite
(alteration - undifferentiated / regional alteration): kaolinite
(mineralization / mineralization zone): pitchblende, coffinite, uraninite
Deposit shape: multiple lenses; Component: mineralization zone
Deposit dimensions:intermediate axis: 230 metres
length: 150 metres
thickness: 75 metres

lensoid; Component: main zone
Deposit dimensions:length: 230 metres
intermediate axis: 70 metres
thickness: 25 metres
Qualified comments: (Applies to: location and access) The Millenium Uranium Zone is located 0.48 km) immediately east of a small northeast trending lake that is located immediately west of Moon Lake.

(Applies to: discovery and development) The Millennium deposit, discovered in 2000 by Cameco Corporation, represents a significant discovery of basement-hosted variant of the Unconformity-associated deposits, in which the mineralization is localized on the footwall side of a graphitic structure at 600 m depth. It currently ranks as second in size to the Eagle Point deposit among the conventionally mine-able basement-hosted deposits of the Athabasca basin. Discovery hole CX-40 was drilled in 2000 and targeted at hydrothermal alteration in adjacent hole; it intersected weak to moderate mineralization over 150 m at 608-761 m depth, including 3.63 % U over 30.3 m.

(Applies to: mineralization) Strata-bound mineralization is restricted to the metapelitic and metasemipelitic beds of the Wollaston Group that were thrusted over granitic gneiss along a fault with a well developed breccia zone. Rotated bedding in the overlying Athabasca Group is more pronounced near the unconformity and is interpreted to be the result of structural dragging of the flat-lying beds in the hanging wall adjacent to the reverse or thrust fault. The fault is interpreted to have allowed penetration of oxidized uranium-bearing basinal fluids into the relatively reduced basement rocks, and consequent deposition of uranium. Association of mineralization with graphitic horizons in the basement is common among the Unconformity-associated deposits. The monometallic character of the Millennium deposit, however, contrasts with polymetallic character of most of these deposits, which generally contain significant amounts of Ni, Co and As. Localization of the main zone of the deposit on the footwall side of a highly graphitic marker unit is also unusual. Weaker persistent mineralization occurs in the lower pelitic-semipelitic strata referred to as the 'Bracketed Assemblage'. The deposit as whole has a gentle plunge to the south. Hydrothermal alteration associated with the deposit is strongly developed on the hanging wall side of the reverse or thrust fault, and is poorly developed on the footwall side of the fault.

(Applies to: geophysical surveys) Discovery of the basement-hosted Millennium deposit at 600 m depth in a region of mature exploration provides impetus for further exploration. It resulted from progressive drill step-outs westward from a north-south segment of the main B1 conductor defined by early (1985-'95) Fixed Loop TDEM EM survey. Difficulty in intersecting the conductor resulted from significant unconformity relief, presence of unresolved conductors in the survey and granite structurally above the thin metasedimentary belt. However, favourable data on sandstone geochemistry and structure, and ultimately good basement alteration in the drill hole CX38 led to drilling of hole CX40 nearby that led to intersection of weak to moderate uranium mineralization over core length of 150 m from 608-761 m vertical depth. Recent geophysical work in the area has included an airborne triaxial magnetic gradiometer survey and MEGATEM test, as well as ground Moving Loop and sounding TDEM, AMT. 2D/3D resistivity and gravity surveys with objective of contributing to the additional discoveries. They represent application of innovative geophysical techniques in the Athabasca basin.

(Applies to: regional stratigraphy) Mineralized lenses are hosted by a 75 m thick stratigraphic zone of two pelitic-semipelitic assemblages separated by a thin calc-silicate unit, over 250 m strike and 150 m depth below the Athabassca unconformity. A highly graphitic pelitic gneiss is a marker unit along the upper margin of the host stratigraphic zone, and the high grade mineralization of the main zone is localized along the footwall of this marker unit.

(Applies to: reserve/resource descriptions) Drill indicated resources as of Dec. 2004: 547000 tonnes ore at 2.43 % U; plus 293000 t at 2.07 % U classified as inferred resources; total of 840000 t ore averaging 2.306 % U and containing 19370 t U.
Links to other databases: SMDI; Key value: 2742
Geophysical-chemical signature: Signature type: Ground EM; Response type: positive (moderate)
Signature type: Airborne Magnetometer; Response type: positive (moderate)
Signature type: Ground Gravity; Response type: positive (weak)
Signature type: Ground IP Resistivity; Response type: positive (moderate)
References:
Anonymous, 2005
Cameco Corporation Annual Information Form for the Year Ended December 31, 2004; Dated March 15, 2005
Annual Company Report, Cameco Corporation, Cameco Corporation, 179 p..

Powell, B.; Leppin, M.; Wood, G.; O'Dowd, C.; Brisbin, D., 2005
Recent Innovative Applications of Geophysics to New Uranium Discoveries in the Athabasca Basin
Topic: Uranium Exploration, In Symposium on Uranium Production and Raw Materials for Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security (IAEA-CN-128): Extended Synopses, Edited by Anonymous, International Atomic Energy Agency Conference (International Symposium), IAEA in co-operation with OECD/NEA, WNA, NEI and UN-ECE, International Atomic Energy Agency, CN-128, 344 p., p. 112 - 114

Powell, B.; Leppin, M.; Wood, G.; O'Dowd, C., 2006
Recent Innovative Applications of Geophysics to New Uranium Discoveries in the Athabasca Basin
Topic 3, Section Uranium Exploration, In Uranium Production and Raw Materials for the Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security; Proceedings of an International Symposium, Vienna, 20-24 June, 2005, Edited by Anonymous, Proceedings, International Atomic Enery Agency; OECD; World Nuclear Association; Nuclear Energy Institute; UN Economic Commission for Europe, International Atomic Enery Agency, Vienna, Austria, STIPUB1259, 352 p., 1 disks, p. 169 - 178

Roy, C; Halaburda, J.; Thomas, D.; Hirsekorn, D., 2006
Millennium Deposit - Basement-hosted Derivative of the Unconformity Uranium Model
Topic 2, Section Uranium Geology and Deposits, In Uranium Production and Raw Materials for the Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security; Proceedings of an International Symposium, Vienna, 20-24 June, 2005, Edited by Anonymous, Proceedings, International Atomic Enery Agency; OECD; World Nuclear Association; Nuclear Energy Institute; UN Economic Commission for Europe, International Atomic Enery Agency, Vienna, Austria, STIPUB1259, 352 p., 1 disks, p. 111 - 121

Roy, C.; Halaburda, J.; Thomas, D.; Hirsekorn, D., 2005
Millennium Deposit - Basement-hosted Derivative of the Unconformity Uranium Model
Topic: Uranium Geology & Deposits, In Symposium on Uranium Production and Raw Materials for Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security (IAEA-CN-128): Extended Synopses, Edited by Anonymous, International Atomic Energy Agency Conference (International Symposium), IAEA in co-operation with OECD/NEA, WNA, NEI and UN-ECE, International Atomic Energy Agency, CN-128, 344 p., p. 42 - 45

Saskatchewan Geological Survey, 2003
Geology, and Mineral and Petroleum Resources of Saskatchewan
Miscellaneous Report, Saskatchewan Industry and Resources, Publication code 2003-7, 173 p., 4 maps.

Resource data:
Disclaimer - Reserves/Resource Data

Her Majesty the Queen in Right of Canada, represented by the Minister of Natural Resources (NRCan) does not warrant or guarantee the accuracy, completeness or fitness for any purpose of Reserve and Resource information (Data) contained in this database, including whether the Data is compliant with any securities regulations or standards, and NRCan does not assume any liability with respect to any damage or loss incurred as a result of the use made of the Data.

Resource and reserve figures are historical in nature. The Data source provided with each set of figures should be cited if the Data are re-reported.

Estimate date: 2004-12-31; 840,000 metric ton ore; Combined with production?: no; Provisional entry?: no; Resource category: geological resource
Grade-commodity information:U: 2.306 percent
weight-commodity information:U: 19,370 metric ton
Reference: Roy, C.; Halaburda, J.; Thomas, D.; Hirsekorn, D., 2005: Millennium Deposit - Basement-hosted Derivative of the Unconformity Uranium Model; Topic: Uranium Geology & Deposits, In Symposium on Uranium Production and Raw Materials for Nuclear Fuel Cycle - Supply and Demand, Economics, the Environment and Energy Security (IAEA-CN-128): Extended Synopses, Edited by Anonymous, International Atomic Energy Agency Conference (International Symposium), IAEA in co-operation with OECD/NEA, WNA, NEI and UN-ECE, International Atomic Energy Agency, CN-128, 344 p., p. 42 - 45
Percent weights allocated to deposit: 100.0%

Generated 2007-03-02 2:36:35 PM with GQuery -- 3.7 ADO (3.19/3.20/3.21 -- 2006-02-24)
GlobalDB System, Geological Survey of Canada, Natural Resources Canada