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


DEPNO COUNTRY LOCATION ALLNAMES COMMODITIES
40046 Canada (Northwest Territories) 62.38.26 N -- 104.59.53 W Boomerang Lake Prospect; Boomerang Prospect U; Au; Cu; Ni; V

Database name: Uranium Deposits, Athabasca Basin
Custodial agency: Geological Survey of Canada
Compilers: Sunil S. Gandhi
Release date: 2007-03-02
   
Deposit name(s): Boomerang Lake Prospect; Boomerang Prospect
Political location(s): Canada; Province or state: Northwest Territories; Nearest community: Yellowknife (560 km E)
NTS map data: 075I10 (High Island)
Deposit clan (type): Unconformity-associated
Deposit (sub) types: Unconformity-associated - Proterozoic - clay-bound; uranium-gold mineralization in basal Mesoproterozoic Thelon Formation sandstone overlying graphitic metapelite of a Paleoproterozoic sequence; lateritic paleosol developed beneath flat-lying sandstone; Reference: Davidson, G. I.; Gandhi, S. S., 1989: Unconformity-related U-Au Mineralization in the Middle Proterozoic Thelon Sandstone, Boomerang Lake Prospect, Northwest Territories, Canada; Economic Geology, Volume 84, p. 143 - 157
Deposit status: drilled showing; Size category: unknown
Geologic province: Churchill - Rae Craton
Geologic subprovince: Amer Fold Belt
Geologic district: Southwestern Thelon Basin
Deposit object located: drill hole
Commodities: U; Au; Cu; Ni; V
Metallogenic signatures: U-Au
Mineralogy: (mineralization): pitchblende
Qualified comments: (Applies to: location and access) The showing is located south of the Thelon Game Sanctuary about 30 km southwest of Beaverhill Lake, 560 km east of Yellowknife. Most of the claims in the area cover the contact between the Thelon Formation and basement rocks. Access to the claims is best achieved by Float- or Ski-equipped aircraft to Boomerang Lake located on the northwest corner of the property.

(Applies to: discovery and development) The Boomerang Lake showing is the first polymetallic unconformity-type uranium prospect identified in the Thelon Basin. The first drill holes were completed in 1983 and drilling has sporadically continued until the present. Mineralization appears to be discontinuous and is only intersected in a few drill holes. There are many strong VLF conductors on the property, but due to a lack of exposed bedrock and a complex faulting history, many more drill holes will be required to determine the extent of this showing. Previous drill programs tested conductors in 1983 and 1991-2 respectively, and 51 holes totaling 6,536.7 metres were completed. The best results were obtained from hole 21 (BL-83-21) which intersected 22.4 g/t Au, 12.3 g/t Ag and 5,003 ppm U3O8 over 0.5 meter in strongly altered sandstone at the faulted unconformity contact. Other more weakly mineralized zones were intersected in several other drill holes in the area. The most significant results of drilling completed in 1998 were obtained in drill hole BL-98-52 immediately beneath the unconformity, which intersected significant gold (Au), uranium (U), platinum (Pt), palladium (Pd) and silver (Ag) values, as follows: 83.5 - 84.5 metres (1.0m) 10.17 g/t Au, 595 ppm U, 358 ppb Pt, 497 ppb Pd, 5.7 ppm Ag Superimposed on, and beneath this zone is an interval of strong nickel (Ni), cobalt (Co), copper (Cu) and arsenic (As) enrichment as follows: 84.0 - 85.0 metres (1.0m) >10,000 ppm As, 3,640 ppm Ni, 6,090 ppm Co, 419.5 ppm Cu (Uravan Annual Report, 2004).

(Applies to: mineralization) Uranium-bearing mineralization occurs along fractures in basement rocks and the Thelon Formation, as well as along the unconformable contact between the two. The U-Au-Ni-Cu-Co-As metallic signature clearly defines the Boomerang style of uranium mineralization with the polymetallic unconformity-type uranium deposits that occur in the Athabasca Basin such as the high-grade Cigar Lake and Key Lake deposits and represents the first unconformity-type uranium showing in the Thelon Basin (Uravan Annual Report, 2004; Davidson and Gandhi, 1989). The best intersection was in strongly altered, poorly consolidated sandstone immediately above the unconformity; several other intersections in sandstone and basement rocks within 7.5 m if the unconformity showed lower, but distinctly anomalous, concentrations of U-Au. All mineralized intersections are in or close to fractured and/or brecciated host rocks that are altered and proximal to the unconformity.
Links to other databases: NORMIN; Key value: 075INE0001
GSC U-Th File (Prasad); Key value: 10121
References:
Davidson, G. I.; Gandhi, S. S., 1989
Unconformity-related U-Au Mineralization in the Middle Proterozoic Thelon Sandstone, Boomerang Lake Prospect, Northwest Territories, Canada
Economic Geology, Volume 84, p. 143 - 157

Gandhi, S. S., 1989
Geology and Uranium Potential of the Thelon Basin and Adjacent Basement in Comparison with the Athabasca Basin Region
In Uranium Resources and Geology of North America, Edited by Anonymous, TECDOC, International Atomic Energy Agency, Vienna, International Atomic Energy Agency, Vienna, Austria, 500, 529 p., p. 411 - 428

Gandhi, S. S., 1995
An Overview of the Exploration History and Genesis of Proterozoic Uranium Deposits in the Canadian Shield
Exploration and Research for Atomic Minerals, Department of Atomic Energy, India, Volume 8, p. 1 - 48

Gibbins, W. A., 1985
Southeast Mackenzie District, Mineral Industry Report, 1982-83, Northwest Territories
EGS, Department of Indian Affairs and Northern Affairs, Publication code 1985-4


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