SMDI #

2533

Historical Showing Names

McArthur River Mine, P2 North Uranium Deposit

Project Name

McArthur River

UTM Northing (NAD83 Z13)

6402070.0000

TRM (Township-Range-Meridian)

101-19-2

Associated Commodities

Arsenic, Cobalt, Copper, Graphite, Nickel

Status

Deposit: Production

Geological Domain

Wollaston

Host Minerals

Arsenopyrite

Exploration History

12/1/2023 After falling to a 10-year low in both uranium production and sales volumes in 2020 (10.1M and 7.5M lb tri-uranium octoxide (U3O8), or 4581 t U3O8 and 3402 t U3O8, respectively), Saskatchewan rebounded to produce 12.2M lb (5534 t) U3O8 and sold over 14.5M lb (6577 t) U3O8 in 2021. A steady increase in the spot price of uranium precipitated the recommissioning of the McArthur River mine and the Key Lake mill in November of 2022. The operations had been suspended since 2018 due to prolonged weak commodity prices. The restart of this mine helped Saskatchewan achieve an annual total production of 19.2M lb (8723 tonnes) U3O8 in 2022, which is significantly higher than in recent years. (Saskatchewan Exploration and Development Highlights 2023, p.3) The remaining production of uranium for 2022 came from the recently restarted McArthur River–Key Lake (Cameco) operation, which yielded a total of 1.1M lb (498.9 t) U3O8 (100 per cent basis) in the fourth quarter of 2022. Cameco has predicted a total production of 14.0M lb (6350.3 t) U3O8 in 2023 from this operation. Production forecasts for 2023 have been adjusted from 15.0M lb (6803.9 t) U3O8 due to equipment reliability issues coming out of care and maintenance, availability of skilled and experienced personnel, supply chain challenges on the availability of materials and reagents, and operational changes that were implemented while restarting the McArthur River–Key Lake operation. (Saskatchewan Exploration and Development Highlights 2023, p.7) (See also Production and Reserves/Resources, from Saskatchewan Exploration and Development Highlights 2023, Tables 1 & 2, p.7-8) 12/1/2024 A steady increase in the spot price of uranium resulted in the recommissioning of the McArthur River mine and the Key Lake mill in November of 2022. The operations had been suspended since 2018 due to prolonged weak prices. The restart of this mine helped Saskatchewan achieve an annual total production of 19.2M lb (8723 tonnes) U3O8 in 2022 and 32.0M lb U3O8 in 2023, both of which were significantly higher than in previous years. In 2024, due to increased production at the McArthur River mine, estimates indicate that Saskatchewan could produce an additional 4.0M lb of U3O8 , reaching 36.0M lb. Total 2024 production is estimated to be split equally between McArthur River and Cigar Lake mines, with each producing 18.0M lb. Updated Reserves of U3O8 at McArthur River dropped by 3.43% for 2024 but maintained a grade of 6.72% U3O8 . (Saskatchewan Exploration and Development Highlights 2024, p.7-9) (See also Production and Reserves/Resources, from Saskatchewan Exploration and Development Highlights 2024, Tables 2 & 3, p.7-9) 6/4/1993 The showing area was first staked as Asamera Incorporated Permit No. 1. The permit was later converted to MPP 1009. Between 1976 and 1979, Asamera Incorporated completed a reconnaissance program over the permit which included airborne INPUT, magnetic, radiometric, INPUT and VLF surveys, ground geophysical surveys, lake sediment sampling, and 3,100 m of reconnaissance diamond drilling. In 1980, SMDC took over operatorship of the McArthur River Project. In the summer of 1981, regional prospecting (AF 74H10-0051) resulted in the discovery of the BJ Main boulder train (SMDI 2158). In 1982, SMDC staked CBS 8818 within MPP 1009 to cover the boulder train and the potential mineralization sources. SMDC also completed a regional program of prospecting, soil gas sampling, lake sediment sampling, ground EM-16 and 37 DEEPEM, gravity and resistivity surveys, and 21 drill holes (AF 74H10-0052, -0054, and-0056 and 74H11-0039 and -0040) in an effort to locate the source of the boulder train. A second boulder train - the BJ East radioactive boulder train (SMDI 2158) - was discovered on grid 82-1. A petrographic study was completed of the BJ-Bonus boulder fields (AF 74H11-0037) and the boulder fields were geologically mapped (AF 74H11-0051). An 1982, an airborne survey was flown over the property (AF 74H11-0035). In 1983, SMDC completed ground VLF-EM, magnetic, gravity, and DEEPEM surveys (AF 74H10-0057), detailed prospecting of grid 81-2 (AF 74H10-0059), and flew an INPUT survey (AF 74H10-0058). In the winter of 1983, 10 drill holes (MAC-91 to -100) were completed (AF 74H11-0053). Twenty two drill holes were completed on the 82-1 grid to test mineralization at the head of the main boulder train (AF 74H11-0052 and -0053) and a further 13 reconnaissance drill holes were completed (AF 74H11-0058 and -0059). Between 1981 and 1983, SMDC completed a regional lake sediment survey (AF 74H10-0060) on the property. In 1984, SMDC completed a core petrographic study of reconnaissance drill holes MAC-1 to -100 (AF 74H10-0062). Ground DEEPEM, gravity, and magnetic surveys were completed (AF 74H10-0063). Regional and detailed prospecting, geological mapping, ground resistivity, magnetic, radon, radiometric, and geochemical surveys were completed and six drill holes (MAC-123 to -128) were completed on the P2 and 82-1 grids (AF 74H10-0064). In 1985, SMDC completed DEEPEM, AMT, gravity, magnetic, and lake sediment surveys and 16 drill holes on the P2 and 82-1 grids (AF 74H15-0032). The drill program discovered both the BJ Uranium Deposit (SMDI 2170) and the P2 Main Uranium Deposit (SMDI 2171). In 1986, SMDC completed a small AMT survey, core XRD and petrographic studies, and drilled 7 holes (MAC-146 to 152) on the P2 Main Deposit (AF 74H15-0035). Significant mineralization was intersected by a number of the drill holes. In the following year, SMDC completed drill holes (MAC-170 to 183) , mineralization age dating, and ore reserves calculations on the P2 Main Deposit (AF 74H-0040). Ground EM-37 and TDEM surveys were completed on the Baxter West grid along the boundary between ML 5481 and CBS 7630 (AF 74H-0034). In 1988, SMDC completed further mineralization age dating, and core magnetic susceptability studies on both the BJ and P2 mineralization. Boulder and outcrop sampling and a further 10 drill holes (MAC-184, -185, and -190 to -198) were completed in the immediate area of the P2 Main deposit (AF 74H-0041). Drill hole MAC-195 discovered the mineralization which has been named the P2 North Uranium deposit or SMDI 2533. The discovery intersection returned 4.27% U3O8 over 10.0 m. Follow-up holes MAC-196 to -198 were completed. In 1989, Cameco completed thirteen drill holes (MAC-199 to -211) and drill core petrography on the P2 North Deposit and prospecting, boulder sampling, and EM, TDEM, UTEM, CSAMT, gravity, and magnetic surveys on the P2 grid (AF 74H-0042 and 74H14-0015). In 1990, Cameco completed drill holes MAC-212 to -216, ground CSAMT, magnetic, gravity, UTEM, TDEM, VLF-EM and resistivity surveys, age dating, and reserves, density, and petrographic studies on the deposit (AF 74H-0046). They also completed age dating on core from drill hole RL-68, a ground TDEM survey, and drill holes RL-66 to -73 on the deposit (AF 74H11-0084). In 1991, Cameco and Uranerz completed drill holes RL-75 to -79 to test for a southern extension of the P2N conductor (AF 74H11-0085). The drilling failed to encounter significant mineralization. In the same year delineation drill holes MAC-227 to -241 were completed on the P2 North Deposit and ground TDEM, VLF-R and boulder sample surveys were completed on the P2N grid (AF 74H-0048). Cameco, as operator, completed hydrogeological and geotechnical studies (AF 74H14-0028), pre-mining feasibility studies, a financial analysis, and environmental studies (AF 74H14-0029), a proposal for underground development and waste management (AF 74H14-0030), soil sampling at the mine site and air strip (AF 74H14-0031), ore metallurgical reports and bench scale investigations (AF 74H14-0032), drill holes MAC-242 to -257 and 25 geotechnical holes (AF 74H14-0033), and a detailed environmental impact study which included proposed underground development (AF 74H14-0034). In 1992, Cameco acquired Agip Resources 10% ownership in the deposit for for $49.8 million. At this time the reserves of the P2 North Deposit were given. Primary engineering studies were completed (AF 74H14-0035). On 24 February 1993, Cameco listed the McArthur River Project reserves. Between 1993 and 1994, Cameco completed shaft to 630 m (2066.9 ft) and drift work on the 500 m (1640.4 ft) level, and to completed infill drilling on the deposit. The EIS report is prepared and hearings were held in 1995. Underground mining will be conducted by using box hole boring, raise hole boring , and remote box hole stoping. The ore is crushed underground, pumped to surface as a slurry, and trucked to the Key Lake mill which has been modified to process this ore. Tailings are stored at the Deilmann tailings facility (converted Deilmann open pit). A 1993 report detailed further environmental impact studies and mining surface operations (AF 74H14-0036). A 1994 annual report detailed shaft sinking (concrete lined) to the 550 m (1804.5 ft) level, level development, underground geotechnical and pre-advancement drilling, and environmental studies (AF 74H14-0037). On 1 November 1995, the geological reserves of the deposit were released. This includes the mineable reserves. On 11 December 1995, the Environmental Impact Study was submitted. In the 10 March, 1997 Northern Miner, the reserves are given as 416 million pounds U3O8 with an average grade of 15% U3O8. In the winter of 1997 to 1998, the Cameco-Uranerz partnership re-assayed samples from old area boulder sample surveys, completed ground TDEM and magnetic surveys over the mine area drill holes RL-86 to -91 to the east of Read Lake and northwest of the mine site to test the CA and CB conductors (AF 74H14-0043). On 18 September 1997, ML 5481 was converted to ML 5516. In their 1998 annual report, Cameco upgraded the deposit reserves and resources total. In the same year, Cameco completed 189 underground drill holes on the 530 m (1738.8 ft) level, shaft sinking to the 580 m (1902.9 ft) level, underground development on the 530 m level, and the 8450N crosscut as well as air quality studies and waste rock radiation measurements (AF 74H14-0039 and -0040). In the same year a Cameco-Uranerz-Cogema partnership completed 39 drill holes (359 to 379, 389 to 441 odd only), 13 hydrogeology holes (H38-1 to 13), and air and water quality monitoring at the mine site (AF 74H14-0046). On 6 October 1999, Cogema Resources Inc. announced that the AECB had granted a two year operating licence for the mine. Production is expected to commence in November once the commissioning process for the Key Lake mill is complete (Saskatoon Star Phoenix - 9 October). In the same year, a Cameco-Uranerz-Cogema partnership completed 31 delineation holes (443 to 501 and 507 odd only), pre-production and water and air quality tests (AF 74H14-0047). By the end of 1999, freeze hole drilling was completed on the largest known high grade uranium deposit in the world, the freezing system was completed, shaft No. 2 was completed, work had started on shaft No. 3, all construction of surface facilities was complete, and mine commissioning had commenced. Underground development was completed on the 530 m (1738.8 ft) and 640 m (2099.7 ft) levels. Pod 2 pelite ore will be mined first using raisebore mining and boxhole boring non-entry methods. Ore will be crushed on the 640 m level and then will be pumped to the Key Lake mill for processing. In this year, Cameco completed drill holes RL-92 to RL-96 and ground TDEM, resistivity, magnetic, and soil gas surveys on the deposit (AF 74H14-0044). The Exploration Highlights 2000 gave revised figures for the total reserves and resources of the deposit. In January of 2000, the first ore was delivered by truck to the Key Lake mill. Commercial production commenced 1 November 2000. On 31 December 2000, Cameco released revised proven, probable, and indicated reserves for the deposit. Between 2000 and 2001, a Cameco-UEM Inc. partnership completed a bouger gravity survey that covered the showing (AF 74H11-0100). In 2002, a partnership involving Cameco, UEM INC., and Cogema Resources Canada completed ground resistivity, gravity, and AMT surveys over the deposit area (AF 74H11-NE-0103). In the following year, the partnership completed an airborne magnetic gradiometer survey and a ground resistivity survey that covered the showing (AF 74H-0058). At 7:20 a.m. on 6 April 2003, the mine experienced a heavy influx of water into the development area of the mine at the 510 m level while miners were excavating a development drift. A 10 m (32.8 ft) long portion of the roof suddenly caved in. Cameco intitally estimated that 700 cubic meters of Athabasca Formation water per hour is entering the mine (11 April 2003 Regina Leader Post page F9). A semi-autogenous grinding mill located on the 640 m level was fully submerged. By mid April, 900 cubic meters of water per hour were inflowing (pumping capacity at this time was 1000 cubic meters per hour) into the development shaft and the 530 and 640 m levels were effected. A concrete barrier was installed on the 510 m level and the water is pumped into an inactive portion of the mine before sending it to surface for treatment. Mining ceased until the water inflow can be stopped. The inflow was stabilized and the effected area was sealed off. Between 2001 and 2002, a partnership involving Cameco, UEM Inc., and Cogema Resources flew a GEOTEM survey that covered the showing, re-sampled existing drill holes, and completed drill hole MC-265 (AF 74H-0059). Drill hole MC-265, which was completed near hole MAC-191, failed to intersect significant uranium mineralization. On 30 June 2003, underground production resumed with two raise bore machines. Mining is expected to return to full capacity (3 raise bore machines) early in July of 2003. In 2004, a ground TDEM was completed that covered the deposit (AF 74H11-NE-0106).

Reserves and/or Resources

2024-12-01 Summary: McArthur River: Measured and Indicated Mineral Resource - Uranium: 7,000,000.00 lb @ 2.3 % McArthur River: Inferred Mineral Resource - Uranium: 2,400,000.00 lb @ 2.9 % McArthur River: Proven and Probable Mineral Reserve - Uranium: 380,500,000.00 lb @ 6.72 % 2023-12-01 Summary: McArthur River: Measured and Indicated Mineral Resource of 6,800,000.00 lb - Uranium @ 2.23 % McArthur River: Inferred Mineral Resource of 2,500,000.00 lb - Uranium @ 2.89 % McArthur River: Proven and Probable Mineral Reserve of 394,000,000.00 lb - Uranium @ 6.7 % 2021-12-31 Summary: McArthur River: Probable Mineral Reserve of 575,100.00 tonne - Uranium: 65,100,000.00 lb @ 5.13 % McArthur River: Indicated Mineral Resource of 74,500.00 tonne - Uranium: 3,700,000.00 lb @ 2.26 % McArthur River: Proven Mineral Reserve of 2,139,600.00 tonne - Uranium: 328,900,000.00 lb @ 6.97 % McArthur River: Inferred Mineral Resource of 41,000.00 tonne - Uranium: 2,600,000.00 lb @ 2.85 % McArthur River: Measured Mineral Resource of 91,700.00 tonne - Uranium: 5,300,000.00 lb @ 2.63 % 2019-03-29 Summary: McArthur River: Proven Mineral Reserve of 2,034,000.00 tonne - Uranium: 320,200,000.00 lb @ 7.14 % McArthur River: Inferred Mineral Resource of 80,500.00 tonne - Uranium: 4,000,000.00 lb @ 2.25 % McArthur River: Probable Mineral Reserve of 538,500.00 tonne - Uranium: 71,700,000.00 lb @ 6.04 % McArthur River: Indicated Mineral Resource of 35,100.00 tonne - Uranium: 2,200,000.00 lb @ 2.86 % McArthur River: Measured Mineral Resource of 97,800.00 tonne - Uranium: 5,500,000.00 lb @ 2.57 % 2005-01-01 Reserves of 419.5 M lbs U3O8 grading 24.59% U3O8. Mineable resource of 17.3 M lbs U3O8 grading 9.42% U3O8. Summary: Historic resource (unspecified) of 419,500,000.00 lb - Uranium: 419,500,000.00 lb @ 24.59 % Mineable resource: Historic reserve (unspecified) of 17,300,000.00 lb - Uranium: 17,300,000.00 lb @ 9.42 % 2002-12-31 175,672 t U grading 19.51% U. Summary: Historic reserve (unspecified) of 175,672.00 tonne - Uranium: 175,672.00 tonne @ 19.51 % 2001-12-31 McArthur River Project: Reserves Thousand Pct Total Million Tonnes U3O8 Lbs U3O8 __________________________________________ Proven 898.3 23.32 461.7 Probable 36.0 15.24 12.1 Resources: Measured 13.5 5.36 1.6 Indicated 519.5 9.59 109.9 __________________________________________ Summary: Historic indicated resource of 519,500.00 tonne - Uranium: 519,500.00 tonne @ 9.59 % Historic reserve (unspecified) of 135,000.00 tonne - Uranium: 135,000.00 tonne @ 5.36 % Historic probable reserve of 36,000.00 tonne - Uranium: 36,000.00 tonne @ 15.24 % Historic proven reserve of 898,300.00 tonne - Uranium: 898,300.00 tonne @ 23.32 % 2001-12-31 394.5 million lbs U3O8 (207,516 tonnes U) with an average grade of 21.0% U3O8. Summary: Historic reserve (unspecified) of 207,516.00 tonne - Uranium: 207,516.00 tonne @ 21 % 2001-02-05 845,000 tonnes grading 21.18% U3O8. Summary: Historic reserve (unspecified) - Uranium: 845,000.00 tonne @ 21.18 % 2000-12-31 TONNES AVERAGE GRADE MILLION X 1000 % U3O8 LBS U3O8 __________________________________________ Proven 768 21.00 355.5 Probable 77 23.04 39.0 TOTAL 845 21.18 394.5 __________________________________________ Indicated 614 10.74 145.5 Summary: Historic proven reserve of 768,000.00 tonne - Uranium: 355,500,000.00 lb @ 21 % Historic indicated resource of 614,000.00 tonne - Uranium: 145,500,000.00 lb @ 10.74 % Historic probable reserve of 77,000.00 tonne - Uranium: 39,000,000.00 lb @ 23.04 % 2000-11-24 Total reserves: 98,160 t U (255.2 million lbs U3O8) at an average grade of 14.7% U (17.33% U3O8). Resources: 87,600 t U (227.8 million lbs U3O8) grading 10.2% U (12.03% U3O8). Summary: Historic resource (unspecified) - Uranium: 227,800,000.00 lb @ 12.03 % Historic reserve (unspecified) - Uranium: 255,200,000.00 lb @ 17.33 % 1998-12-31 Reserves: 483 million pounds U3O8. Summary: Historic reserve (unspecified) - Uranium: 483,000,000.00 lb 1997-03-10 Reserves: 416 million pounds U3O8 with an average grade of 15% U3O8. Summary: Historic reserve (unspecified) - Uranium: 416,000,000.00 lb @ 15 % 1995-11-01 Geological reserves: 416 million pounds U3O8 grading 15%. Mineable reserves: 457,000 tonnes ore grading 18.8%. Summary: Geological reserves: Historic reserve (unspecified) - Uranium: 416,000,000.00 lb @ 15 % Mineable reserves: Historic reserve (unspecified) - Uranium: 457,000.00 tonne @ 18.8 % 1993-02-24 McArthur River Project reserves: 2,370,000 tonnes grading 5.00% U3O8 or 260,000,000 pounds U3O8. Summary: McArthur River Project: Historic reserve (unspecified) - Uranium: 260,000,000.00 lb @ 5 % 1992-01-01 Cameco – Uranerz Deposit reserves: 100,000 tonnes with an average grade of 4.24% U. Summary: Historic reserve (unspecified) - Uranium: 100,000.00 tonne @ 4.24 %