SMDI #

2153

Historical Showing Names

Cluff Lake Mine, Dominique Janine North Deposit; Dominique Janine South Extension (DJX) Open Pit; West Dominique Janine Mine; Dominique Janine South Deposit

Project Name

Cluff Lake

UTM Northing (NAD83 Z13)

6478504.6200

TRM (Township-Range-Meridian)

108-22-3

Associated Commodities

Graphite, Iron, Lead, Molybdenum

Status

Deposit: Post-Production [Institutional Control Program]

Geological Domain

Beaverlodge

Host Minerals

Molybdenite, Pyrite

Exploration History

1/1/2013 Most of the physical decommissioning was completed by 2006, and in 2013, access to the site became unrestricted as Orano’s full-time occupation ended (though annual environmental monitoring and regulatory inspections trips are still conducted). Risk assessments predict long-term stability and safety, and the site is doing well: over 650,000 trees have been planted, flourishing alongside returning grasses and blending the area back into nature. 5/10/1990 The area of the orebody was under exploration as early as 1958 when airborne magnetic and radiometric surveys were completed for W.S. Kennedy (1958) Grubstake to test two topographic features, a circular pattern and a southwest-striking lineament. Three magnetic anomalies were located; one north of Carswell Lake, a second 2 miles (3.2 km) east of the central part of Carswell Lake, and a third zoned circular pattern centred 3 miles south of Carswell Lake. All radiometric anomalies corresponded to the circular pattern. An airborne gammametic survey was completed over the area in 1967 to 1968, and CBS 2330 and CBS 2331 were staked 2 August 1968 in response to the survey results. A detailed airborne scintillometer survey was completed over the area in 1969 which outlined several anomalies. Radon surveys were completed in areas of radioactive boulders but nothing was located. Ground magnetometer surveys as well as stripping and trenching was completed over the anomalous areas and several boulders containing pitchblende with associated Au, selenides and tellurides were located east of Cluff Lake. Data from an airborne magnetic survey was geologically interpreted. The showing area, geologically, was split into three lithologic groups, granite intrusion and intense granitization, granite gneiss, and amphibolite gneiss. A helicopter-borne scintillometer survey was completed as well as ground resistivity surveys, stripping and trenching on the Claude Deposits. A geochemical survey was subsequently completed. In 1971, an airborne EM (input) survey was completed over the area which outlined 10 conductive zones, none pertaining to the showing. Ground radiometric surveys were completed over grids in the more anomalous areas which outlined pitchblende pebbles and mineralized bedrock pebbles. General resistivity surveys were completed in the area east and north of Cluff Lake as well as more detailed surveys in the more anomalous areas. VLF-EM and geochemical surveys were also completed as well as trenching, diamond drilling and percussion drilling. No interesting results are listed. Significant work began in 1972 to 1973 with scintillometer surveys, radon emanometry surveys, geochemical surveys, geological mapping, trenching, VLF-EM surveys, gravimetry and seismic reflection surveys, diamond drilling, percussion drilling and an airborne spectrometer survey over the showing area. A resistivity survey, completed in the area, outlined northwest-striking fault zones. A VLF-EM survey outlined the tangential-radial fault pattern expected of the Carswell structure. Strategic geochemical surveys were carried out in 1975 which outlined several anomalies, and continued diamond and percussion drilling was done. Geological mapping and radiometric prospecting, geochemical sampling and radon surveying were completed as well. In 1976, the claim was converted to ML 5186. In 1979, geological mapping in the Claude Deposit exploration adit disclosed highly mineralized zones of Cluff Breccia. This led to a re-evaluation of the Dominique area breccias. In 1980, reconnaissance drilling of an area located between two airborne magnetic anomalies encountered economic mineralization (4.2 m grading 2.5% U) below the Peter River gneisses. In 1982, development drilling outlined the Dominique-Peter deposit. Later percussion drilling along the Peter River - Earl River contact discovered the Janine North deposit in 1984. In 1987, reserves were reported on the Dominique-Janine deposit. In 1988 overburden stripping was completed on the deposit. In 1989, revised deposit reserves were reported and mining of the Dominique-Janine deposit by open pit commenced. In 1990, the open pit was mined out. Mining at the Janine North open pit commenced in 1990 and by 1991 this pit was mined out. In 1993, public hearings and licencing procedures were held for the Dominique-Janine Extension (DJX) open pit mine. The panel approved the submission and Federal and Provincial governments gave the project a 'go ahead'. In 1994, a GEOTEM airborne survey was flown over the mine site (AF 74K-0012). In the 1995 Prospector's and Developers Exploration and Development highlights, the reserves for the Dominique-Janine Extension were released. The DJX Open Pit, which was exhausted in 1997, yielded 1,195 tonnes U. The DJU (underground) mining, which is accessed (to the 160 m level) by a decline, yielded 1,388 tonnes U between 1994 and 1998 using undercut and fill mining methods. Underground mining has continued. DJU ore was found to be more tectonized, more highly altered, and more variable in thickness and grade than Dominique Peter ore. The West DJ Deposit ore are higher grade than either of the two previously-mentioned deposits. The individual ore pods along the shore of Cluff Lake are typical vein deposits not unconformity type deposits. Between 1998 and 1999, ore was mined from Dominique Peter, DJU, and Dominique Janine West. To 1 January 1999, a total combined production was listed as 19,576 tonnes U (50.9 million pounds U3O8) with an average grade of 0.8% U3O8. Between 1999 and 2001, Cogema planned to selectively mine and process only the higher grade portion of all mine reserves. In 2000, mining of higher grade ore resulted in the filling of the tailings management area at a lower than expected rate. Therefore mining operations, planned to cease in 2000, continued into 2001. Late in 2001, Cogema announced that mining at Cluff Lake would likely cease by May of 2002. Milling will continue as long as stockpiled ore remains. On 31 May, 2002, mining at the Dominique Janine Underground Mine (the Cluff Lake Mine) ceased. The Cluff mill continued to process stockpiled mined ore into December of 2002. Equipment was recovered and the mine raise and ramp was backfilled and a concrete cap was emplaced in each mine opening. On 2 September 2002, Areva Resources Canada Inc. converted ML 5186 to S-107001. In 2003, Cogema made official application for the final decommissioning license. The decommissioning process is expected to take 2 to 3 years. The Cluff mill circuits were cleaned and the mill was mothballed. Cluff Lake production is complete.

Reserves and/or Resources

2002-01-01 0.0 t U. Summary: Dominique Janine Underground Mine: Historic reserve (unspecified) of 0.00 tonne - Uranium: 0.00 tonne 1995-01-01 Dominique Janine Extension reserves: 5,000 tonnes grading 0.37% U. Summary: Dominique-Janine Extension: Historic reserve (unspecified) - Uranium: 5,000.00 tonne @ 0.37 % 1991-01-01 Combined reserves for the Janine pit and Peter-Dominique: 731 tonnes U. Summary: Janine Pit/Peter-Dominique: Historic reserve (unspecified) - Uranium: 731.00 tonne 1990-05-01 Combined Dominique-Janine and Dominique- Peter reserves: 24,000,000 tons U3O8 grading 0.81% U3O8. Combined Janine North and Janine South reserves: 21,000,000 tonnes U3O8 grading 0.68% U3O8. Summary: Dominique-Janine/Dominique-Peter: Historic reserve (unspecified) of 24,000,000.00 ton - Uranium @ 0.81 % Janine North/Janine South: Historic reserve (unspecified) of 21,000,000.00 tonne - Uranium @ 0.68 % 1989-01-01 Dominique-Janine reserves: 23,000 tonnes U grading 3.80% U3O8. Summary: Dominique-Janine: Historic reserve (unspecified) - Uranium: 23,000.00 tonne @ 3.8 % 1987-01-01 Dominique-Janine deposit reserves: 1,000,000 tons grading 0.5% U3O8. Summary: Dominique-Janine: Historic reserve (unspecified) of 1,000,000.00 ton - Uranium @ 0.5 %