SMDI #

2529

Historical Showing Names

McClean Lake Uranium Deposit, McClean Lake Uranium Deposit [Caribou, McClean North, Sue D, Sue E, Ore Stockpile], Sue A Deposit; Sue B Deposit; Sue C Deposit; Sue C-1 Open Pit; Sue CQ Zone; Sue CQQ Zone; Sue D Zone; Sue E Zone; McLean Pod

Project Name

McClean Lake

UTM Northing (NAD83 Z13)

6458465.0000

TRM (Township-Range-Meridian)

107-11-2

Associated Commodities

Arsenic, Cobalt, Copper, Lead, Nickel

Status

Deposit: Development

Geological Domain

Wollaston

Host Minerals

Arsenopyrite

Exploration History

12/1/2023 A total of 19.23M lb (8723 t) tri-uranium octoxide (U3O8) was produced, the majority coming from the Cigar Lake (Cameco Corp.)–McClean Lake (Orano Canada Inc.) operation (Table 1), which accounted for 18.0M lb (8164.7 t) U3O8 (100 per cent basis) in 2022. Cameco forecasted a total production of 16.8M lb (7620.4 t) U3O8 in 2023, adjusting the 2022 number due to initiation of mining a new zone in the orebody and equipment reliability issues. (Saskatchewan Exploration and Development Highlights 2023, p.7) (See also Production and Reserves/Resources, from Saskatchewan Exploration and Development Highlights 2023, Table 1 & 2, p.7-8) 12/1/2024 In January 2024, Orano Canada Inc. (Orano) and Denison Mines Corp. (Denison) announced plans to restart uranium mining operations at the McClean Lake mine in 2025 with production of about 800 000 lbs triuranium octoxide (U3O8) expected that year. Orano and Denison plan to use the patented Surface Access Borehole Resource Extraction (SABRE) technology with recovered ore processed at the McClean Lake mill. (Saskatchewan Exploration and Development Highlights 2024, p.7) (See also Reserves/Resources, from Saskatchewan Exploration and Development Highlights 2024, Tables 2 & 3, p.7-9) 5/4/1993 In 1964, Compagnie de Mokta Ltee commenced uranium exploration in the Athabasca Basin. This work led to the discovery of the Cluff Lake Deposit in 1969. During the same period of time, Dynamic Group formed a joint venture with British American Oil Company to explore for uranium. Gulf Mineral Resources took over this partnership and discovered the Rabbit Lake Deposit in 1968. The discovery or the Rabbit Lake Deposit resulted in a rush of uranium staking and prospecting. By 1971, most of these uranium permits had lapsed. In 1974, a partnership involving Uranerz Exploration and Mining Company, Inexco Mining Company, and SMDC commenced an exploration program which culminated in the discovery of the Gaertner Deposit in 1975 and the Deilmann Deposit in 1976. On 12 August 1974, Vern Studer staked the showing area as CBS 3501 and transferred the property to Canadian Occidental Petroleum. Canadian Occidental commenced exploring the land between the Rabbit Lake Deposit and Midwest Lake for uranium. In 1975, a track etch survey was completed on the property. In 1976, the exploration program included percussion drilling, ground geochemical and geophysical surveys, and a follow-up track etch survey (AF 64L05-0024). In 1977, Canadian Occidental and Inco Limited formed a joint venture partnership to continue exploration of the property. Between 1977 and 1978, the partnership completed airborne geophysical surveys, ground EM surveys, and follow-up diamond drilling (AF 64L05-0023 and -0043). Continued drilling in 1979 resulted in the discovery of the McClean North Deposit (AF 64L05-0047 and -0048). From 1979 to 1980, twelve methods of ground geophysics (including magnetic and VLEM surveys) were completed over the McClean North Deposit area (AF 64L05-0075). On 14 January, 1980, drill hole number 1004 discovered the McClean South Zone. In 1980, airborne INPUT surveys were completed over the property (AF 74I-0005 to -0007). On 12 August 1980, CBS 3501 converted to ML 5290. Between 1980 and 1981, ground EM and magnetic surveys were completed over numerous grids (AF 64L05-0074). In 1981, Clark, Brummer, and Fogwill regionally geologically mapped the property. In the same year, a pre-feasibility study was completed. In 1983, a Canico-Canadian Occidental Petroleum joint venture completed muskeg sampling and a clay content of boulders study for the McClean Deposits (AF 64L05-0084). Lake water/sediment sampling (AF 74I01-0001) and ground EM and magnetic surveys (AF 64L05-0025, -0075, and -0077) were completed. In 1982, Asamera Corporation re-interpreted the 1980 GSC Cotran Survey (AF 64L05-0103). In the winter of 1984, a Canico-Canadian Occidental Petroleum joint venture completed ground VLF-EM surveys over the Black, Snake, and Misty grids on CBS 3501 to CBS 3505 (AF 64L05-0085) in addition to further diamond drilling (AF 64L05-0076). In January of 1985, the partners entered into a joint venture agreement with Total Minatco Company Ltd./Ltee. To further explore ML 5290. In 1986, further EM surveys and follow-up drilling was completed in the McClean to Lasby lakes area (AF 64L05-0118). In 1987, ground VLF-EM, HLEM, and magnetic surveys and drill holes SL-1 to -9 were completed on the Sue Lake grid (AF 64L05-0132). In 1988, further ground geophysics and percussion drilling was completed on the Sue Lake grid (AF 64L05-0133). This work resulted in the discovery of the Sue A and B zones. In 1989, further ground geophysics and diamond drilling was completed on the Sue Lake grid (AF 64L05-0134). This work resulted in the discovery of the Sue C Zone (discovery drill holes CS60 and CS34). In this year, Minatco retained SENES Consultants Limited to prepare an environmental Impact Study on the McClean, JEB, and Sue Deposits. Drilling on the Sue C Zone in 1990 outlined sufficent reserves to warrant possible mining of the C Zone when the A and B zones are mined. On 22 June 1990, the showing area was staked as CBS 7657 within ML 5290 and on 1 August 1990, the remainder of ML 5290 was allowed to lapse. In November of 1990, Minatco acquired the shares of Canadian Occidental and Inco in the project and became sole owner of the deposits. Minatco completed ground IP-resistivity and gravity surveys and drill holes S242 to S304 on the Sue Deposit C and CQ zones (AF 63L05-0135). Drill hole S285 discovered the mineralization which was named the Sue CQQ and Sue D zones. At this time, the deposit reserves were given. In 1991, hydrology test holes PV-6 to -13 were completed on the Sue A to C pit sites, drill holes S-305 to S-408 were completed on the Sue C, CQ, D and E Zones and extensions (AF 64L05-0136). The C and CQ zones were drilled at 12.5 m centres, the Sue D Zone was delineation drilled (14 holes), and drill hole S-395 discovered the Sue E Zone mineralization. In 1992, Minatco completed 87 drill holes (S-409 to 495) and VLF-EM, HLEM, and VLEM surveys were completed on the Sue grid (AF 64L05-0137). Twenty six holes tested the Sue D Zone, fourty two holes tested the Sue E Zone, and nineteen exploration holes were completed. In 1993, the Federal Environmental Assessment Review Office panel was convened to examine the McLean Deposit development proposal. The panel recommended that the project be placed on hold. Late in 1993, the Federal and Provincial Governments gave approval to start development of the ore bodies which constitute this deposit. It is proposed that both open pit and underground methods will be used to mine the zones which comprise the McClean Lake Uranium Deposit. The ore will be processed at the McClean Project mill. In the same year, the partners completed a ground IP/resistivity survey on the Sue grid and further delineation drilling (S-525 to S-555) and condemnation drilling (S-556 to S-571) on the A, B, and C Zones and drill holes S-496 to S-524 were completed to test the Sue North area north of the Sue B Zone (AF 64L05-0138). In 1994, Cogema Canada Inc completed ground gradient array resistivity, VLF-R, and HLEM surveys on the Sue grid (AF 64L05-0142). In 1997, the Sue C Deposit open pit mine commenced stripping operations. In the same year, a Cogema-Minatco partnership completed drill holes S-572 to -594 on the Sue D Zone and a boulder sample survey over the Sue zones (AF 64L05-0143). In the 24 August 1998, Northern Miner (page 3) it was announced that the Atomic Energy Control Board had approved the tailings storage at McClean Lake. The hearing to obtain a mining licence is is scheduled for November of 1998. At this time mineable reserves for McClean Lake were given as 720,000 tonnes grading 3.15% U3O8. In later 1998, the Sue C Deposit open pit was commenced. Ore will likely be encountered by Christmas of 1998 and production is expected to begin early in 1999 (once regulatory approval is granted). The ore was stockpiled and then run through the McLean Mill which useed the JEB Open Pit as a tailings pond. As of 31 December 1997, Denison Mines Limited gave the estimated proved mineable reserves for the Sue Deposits. In 1999, the Sue C open pit was developed to a depth of 80 m (immediately above the ore). This pit will be used to mine both of the Sue A and Sue C deposits. The Sue B deposit will mined as a separate pit. It is planned that the deposits be mined out by 2003 (1999 Exploration and Development Highlights). At the end of 2000, the Sue Pit had 27,340,000 lbs U3O8 in situ. The first yellowcake was produced on 8 July 1999. In January 2000, mining removed ore from the Sue C1 open pit and mining of waste rock from the Sue C2 underground mine commenced. Commercial production commenced on 1 February 2000. In 2001, a partnership involving Cogema Resources, Denison Mines, and OURD completed 31 drill holes (S-646 to S-676) and HLEM and TDEM surveys on the Sue B, D, and E deposits and a ground HLEM survey on the Moffat Nose grid (AF 64L05-SW-0154). Drill holes S-655 and S-659 encountered minor mineralization on the Sue D area and drill hole S-672 encountered minor mineralization where the Sue C trend intersects the Telephone Lake Fault. In the 5 February 2001, Northern Miner, it was announced that McClean mine was the first Canadian mine to be awarded an environmental management certificate. In 2001, the Sue C1 pit was mined out to a depth of 100 m (ore was stockpiled in the pit) and the Sue C2 extension pit had reached a depth of 30 m and was still in sandstone. It was planned that the Sue deposits would be mined out by 2003. On 11 November 2001, Sue C mining set a production record. Over 1,200,000 lbs of ore grading just over 10% U3O8 was mined from the C pit within a 24 hour period. In the winter of 2001, Cogema Resources Inc.and Cameco Corporation completed 28 delineation drill holes (S-624 to S-645 and S-677 to S-682) on the Sue E deposit (AF 64L04-NW-0112). In the December 2001 Cogema Communique, Cogema announced that by the end of December 2001, the Sue C2 extension pit will be mined out. At this point, Cogema stated that they would have enough ore stockpiled to feed the mill for four to five years. Therefore, Cogema announced that it would suspend mining operations. After Christmas, employees would relocate JEB and Sue special waste stockpiles to the mined-out Sue C pit and they would haul stockpiled ore from the mine to the mill storage pad. Once this was completed, the Sue site will shut down. On 29 April 2002, CBS 6802 was re-staked as S-106953 and S-106954. In a news release dated 02 May 2002, Denison Mines Ltd. Announced that the mining of the Sue C deposit was completed on 3 February 2002. At the time of closure, the Sue C1 extension pit was mined out at a depth of 100 m (328.1 ft) and the C2 extension pit was mined out at a depth of 143 m (469.2 ft). The pit produced 650,000 tonnes of ore grading 2.6% U3O8 (14,031 t U or 36.4 M lb U3O8). On 22 June 2006, CBS 7657 was re-staked as ML 5514. In 2002, Cameco completed ground TDEM and HLEM surveys that covered the Sue E orebody (AF 64L04-NW-0113).In the same year, an airborne AeroTem survey was flown which covered the deposits and ground TDEM and Resistivity surveys were completed to the northwest of the deposits on the Caribou Grid (AF 64L05-SW-0156). Denison Mines announced, with the closure of the Sue C Pit, that about 33% more uranium than had been anticipated had been added to surface stockpiles. All mining would cease for the next few years and mineral exploration at McClean would cease until ground conditions improve and until drill results have been assessed. Mining of Sue C Pit ore was completed in February of 2002. The Sue C orebody provided 650,000 t of ore grading just over 2.6% U3O8 and the deposit produced 36.4 M lbs U3O8. At this time, it was suggested that future development of the Sue A deposit would occur from an extension of the Sue C pit and the Sue B deposit would require a separate pit. In 2003, milling of stockpiled ore continued at the McClean Lake mill. At this point, Cogema estimated that the Sue E deposit would be mined in 2005 (depending on the regulatory review results). In 2005, stockpiled Sue C Deposit ore was milled. Mining of the Sue A deposit commenced in July of 2005. In the first year, 3,513,452 tonnes of waste (overburden) was mined. The first ore was mined in December 2005. The deposit should be mined out in February of 2006. Pre-mining overburden stripping at the Sue E deposit commenced in September of 2005. Ore will not be reached until the summer of 2006. In 2006, test mining of the McLean Pod commenced. Initially, it was felt that the pod would be mined using underground methods. The Mine Equipment Development Project (MED) was tasked with testing the feasibility of mining this pod remotely using jet boring ore extraction techniques.

Reserves and/or Resources

2024-12-01 Summary: McClean North: Measured and Indicated Mineral Resource - Uranium: 12,200,000.00 lb @ 2.8 % Sue E: Inferred Mineral Resource - Uranium: 7,300,000.00 lb @ 0.69 % McClean Lake ore stockpile: Proven and Probable Mineral Reserve - Uranium: 700,000.00 lb @ 0.37 % McClean North: Inferred Mineral Resource - Uranium: 10,000.00 lb @ 0.79 % Sue D: Inferred Mineral Resource - Uranium: 20,000.00 lb @ 0.39 % Caribou: Measured and Indicated Mineral Resource - Uranium: 2,800,000.00 lb @ 2.6 % Sue D: Measured and Indicated Mineral Resource - Uranium: 2,800,000.00 lb @ 1.1 % 2023-12-01 Summary: McClean North: Measured and Indicated Mineral Resource of 12,400,000.00 lb - Uranium @ 2.8 % McClean Lake ore stockpile: Proven and Probable Mineral Reserve of 730,000.00 lb - Uranium @ 0.37 % Caribou: Measured and Indicated Mineral Resource of 2,800,000.00 lb - Uranium @ 2.6 % Sue E: Inferred Mineral Resource of 7,300,000.00 lb - Uranium @ 0.69 % Sue D: Measured and Indicated Mineral Resource of 2,800,000.00 lb - Uranium @ 1.1 % Sue D: Inferred Mineral Resource of 200,000.00 lb - Uranium @ 0.39 % McClean North: Inferred Mineral Resource of 100,000.00 lb - Uranium @ 0.79 % 2021-12-31 Summary: McClean North: Indicated Mineral Resource of 204,300.00 tonne - Uranium: 12,200,000.00 lb @ 2.8 % Sue D: Inferred Mineral Resource of 24,200.00 tonne - Uranium: 200,000.00 lb @ 0.39 % McClean North: Inferred Mineral Resource of 3,300.00 tonne - Uranium: 100,000.00 lb @ 0.79 % Ore Stockpile: Proven Mineral Reserve of 90,000.00 tonne - Uranium: 726,000.00 lb @ 0.37 % Sue E: Inferred Mineral Resource of 483,400.00 tonne - Uranium: 7,300,000.00 lb @ 0.69 % Caribou: Indicated Mineral Resource of 47,800.00 tonne - Uranium: 2,800,000.00 lb @ 2.6 % Sue D: Indicated Mineral Resource of 122,800.00 tonne - Uranium: 2,800,000.00 lb @ 1.1 % 2015-01-01 NI 43-101-compliant Measured and Indicated Resource for the Sue D deposit was 121,200 tonnes grading 1.05% U3O8 for 2.8 M lb U3O8. Inferred Resource for the Sue E deposit was 480,900 tonnes grading 0.69% U3O8 for 7.3 M lb U3O8. Summary: Sue E: Inferred Mineral Resource of 480,900.00 tonne - Uranium: 7,300,000.00 lb @ 0.69 % Sue D: Measured and Indicated Mineral Resource of 121,200.00 tonne - Uranium: 2,800,000.00 lb @ 1.05 % 2005-01-01 Reserves (in situ and stockpiled) of 32.9 M lbs U3O8. Summary: Reserves (in situ and stockpiled): Historic reserve (unspecified) - Uranium: 32,900,000.00 lb 2002-12-31 Cogema – Denison – OURD Sue A, B, C, D: 14,115 t U grading 1.53%. Summary: Sue A, B, C, D: Historic resource (unspecified) - Uranium: 14,115.00 tonne @ 1.53 % 2001-01-01 A preliminary estimate of the Sue E Zone indicates about 8 million lbs U3O8 at a grade of 0.98% U3O8. Summary: Sue E: Historic resource (unspecified) - Uranium: 8,000,000.00 lb @ 0.98 % 1998-08-24 Cogema – Minatco Mineable reserves - McClean Lake deposits: 720,000 tonnes grading 3.15% U3O8. Summary: McClean Lake deposits: Historic resource (unspecified) of 720,000.00 tonne - Uranium @ 3.15 % 1997-12-31 Estimated proved reserves - Sue deposits: DEPOSIT THOUSAND GRADE MILLION TONNES ORE U3O8 LBS U3O8 ________________________________________ A 55.0 1.49 1.8 B 90.1 0.86 1.7 C 249.9 5.30 29.2 ________________________________________ Summary: Sue A: Historic proven reserve of 55,000.00 tonne - Uranium: 1,800,000.00 lb @ 1.49 % Sue C: Historic proven reserve of 249,900.00 tonne - Uranium: 29,200,000.00 lb @ 5.3 % Sue B: Historic proven reserve of 90,100.00 tonne - Uranium: 1,700,000.00 lb @ 0.86 % 1990-11-01 Deposit reserves: ZONE PROVEN PROBABLE AVERAGE RESERVES RESERVES GRADE KG U3O8 KG U3O8 % U3O8 _____________________________________ A 0.8 million 0.8 million 1.5 B 0.8 million 0.8 million 0.8 C 11.0 million 24.0 million 5.7 _____________________________________ Summary: Zone B: Historic probable reserve - Uranium: 800,000.00 kg @ 0.8 % Zone B: Historic proven reserve - Uranium: 800,000.00 kg @ 0.8 % Zone A: Historic probable reserve - Uranium: 800,000.00 kg @ 1.5 % Zone A: Historic proven reserve - Uranium: 800,000.00 kg @ 1.5 % Zone C: Historic probable reserve - Uranium: 24,000,000.00 kg @ 5.7 % Zone C: Historic proven reserve - Uranium: 11,000,000.00 kg @ 5.7 %