- SMDI #
- 1713
- Current Showing Name
- Rabbit Lake Mine
- Historical Showing Names
- Rabbit Lake Mine, Rabbit Lake Uranium Mine
- Company Name
- Cameco Corporation
- Project Name
- Rabbit Lake
- UTM Easting (NAD83 Z13)
- 575335.0000
- UTM Northing (NAD83 Z13)
- 6451544.0000
- NTS Sheet
- 064L04
- TRM (Township-Range-Meridian)
- 106-11-2
- Primary Commodities
- Uranium
- Associated Commodities
- Arsenic, Cobalt, Copper, Graphite, Nickel, Selenium, Vanadium
- Discovery Type
- Status
- Deposit: Production (Care and Maintenance)
- Geological Details
- The Rabbit Lake unconformity-type uranium deposit is located on the eastern margin of the Athabasca Basin about 5 km west of Wollaston Lake.
In the general deposit area, the Archean(?) granitoid basement is overlain by a series of 065°/65°SE-trending, commonly graphitic, Lower Proterozoic Wollaston Group rocks. The basal Wollaston Group rocks consist of a series of locally graphitic biotite-cordierite gneisses with feldspathic and quartzitic interlayers. This unit is overlain by a series of calcareous and non-calcareous feldspathic metasediments which contain interlayered calc-silicates and minor biotitic paragneiss. The upper portion of this unit locally hosts massive carbonate (which is the Rabbit Lake Deposit host rock). This unit is overlain by a uppermost unit (the Hidden Bay Assemblage) which consists of a series of ferromagnesium rich metasediments. The Archean-Aphebian units are unconformably overlain by the Paleohelikian Athabasca Group Manitou Falls Formation. These sediments consist of a basal conglomerate and overlying finer grained conglomerates with interbedded sandy layers and shale partings.
At the deposit, the hanging wall (upper gneissic) rocks include a series of albite-rich calc-silicates (massive plagioclastite), fine-grained graphitic granulites, massive layered and unlayered dolomitic marbles, and a series of "Upper Gneisses" which consist of a series of well-layered, red and green gneisses which have alternating red feldspar-scapolite-quartz layers and green diopside-amphibolite-chlorite layers. A series of concordant microcline-rich granitic sills occur in this "Upper Gneiss" unit. The hanging wall rocks are cross-cut by a series of zoned granitic pegmatites and microgranite dykes.
The footwall rocks include Athabasca Group sediments, an altered sub-Athabasca Group sequence of plagioclase-rich calc silicates (Plagioclasite) which form the regolith, and a series of cross-cutting granitic intrusives. The Athabasca Group basal conglomerates and overlying conglomerates and sandstones have a maximum thickness of 25 m (82.0 ft). No uranium mineralization occurs within the Athabasca Group rocks. The underlying hematite-red, fine-grained, fissile regolith rocks consist of highly weathered quartz-biotite-feldspar gneiss.
The Upper Gneisses have been folded into a series of major anticlines and a syncline whose axial planes plunge 6°N. Minor crenulation folding (F4) occurs on the fold limbs and locally within the dolomitic marbles. The altered dolomite and graphitic granulite ore host rocks are separated from the non-mineralized upper gneisses by a 15 to 20 m wide (49.2 to 65.6 ft), vertically dipping zone of mineralized microgranite dyke-breccia. The main structural feature present at the deposit is the Rabbit Lake Fault - a reverse thrust fault which downthrows the Athabasca Group sandstones at least 75 m against the crystalline basement. The trace of this fault varies in width from 1 to 2 m (3.3 to 6.6 ft) at the northeast edge of the pit to 35 m (114.8 ft) at the southwest edge of the pit. This 065°-striking and 30°SE to 60°SE-dipping fault, which defines the footwall of the orebody, is cross-cut by an older northeast-trending, steeply dipping normal fault which bounds the ore to the southwest. A north-south-trending, subvertical fault of unknown age and displacement separates the hanging wall gneisses from the ore host rocks.
The orebody, which occurs on the west limb of a syncline, has the shapeof a laterally flattened pipe, is elongated in a northeast-southwest direction, and is 550 m (1804.5 ft) long, up to 250 m (820.2 ft) wide, and 200 m (656.2 ft) deep. The deposit consists of a high grade core which is surrounded by a lower grade envelope of ore.
The mineralization consists of 5 generations of deposition and remobilization of pitchblende, coffinite, and sklodowskite. Secondary uranium mineralization includes kasolite, massuyite, woelsendorfite, boltwoodite, and uranophane. The uranium mineralization is accompanied by a broad suite of minerals which include minor amounts of marcasite, galena, sphalerite, pyrite, nickelene, chalcocite, clausthalite, and native copper plus euhedral quartz, calcite, dolomite, siderite, hematite, mg-chlorite, dravite, adularia, and carbon buttons. Secondary uranium minerals, uranium mineral coatings, and impregnations are also developed.
The absolute age of the pitchblende mineralization, as determined by U-Pb dating, is 1281±11 Ma. It is estimated that the uranium deposition took place at a temperature of 180°C to 245°C.
The host rocks for the Rabbit Lake deposit have experienced intense alteration. The Footwall assemblage, apart from the weathering associated with the regolith, are unaltered. The hanging wall dolomitic marble shows the most intense alteration and locally forms a megabreccia with unaltered dolomite blocks in a matrix of phyllosilicate. The dolomites have experienced several phases of carbonate remobilization and recrystallization. The graphitic granulites, which have experienced sulphide and graphite depletion during alteration, show sericitization, silicification, dravitization, carbonatization, and an accumulation of terra rosa. The "upper gneisses" display pervasive bleaching, alteration to phyllosilicates, silicification, and carbonatization. The microgranite shows evidence of sericitization, chloritization, and dravitization. In general the alteration can be summarized as hydration, redistribution of B, MgO, and CaO, the leaching of SiO2, Na2O, Fe2O3, and K2O, the introduction of U, Ni, Co, Se, Cu, and S plus the removal or consumption of graphite.
- Geological Domain
- Wollaston
- Host Rocks
- Host Minerals
- Arsenopyrite
- Indicators
- Exploration History
- 12/1/2023
Eagle Point–Rabbit Lake (Cameco) operations will remain in a safe state of care and maintenance pending improvement in market conditions.
(Saskatchewan Exploration and Development Highlights 2023, p.7)
7/13/1988 In 1967, Gulf Minerals flew a regional airborne radiometric survey over the deposit area. Ground follow-up work located a number of radiometric boulders. The boulder train tracing led to the Rabbit Lake area. Subsequent work indicated an EM conductor with an associated magnetic low, a gravity low, and a closely associated lake sediment geochemical anomaly. The 1968 drill hole 7-3 discovered the Rabbit Lake uranium deposit. This hole intersected 50 m (164.1 ft) of pitchblende mineralization in dolomitic and calcareous/graphitic metasediments in the hanging wall of the southerly dipping Rabbit Lake thrust fault. In the following year, Gulf completed drill holes 7-004 to 7-007, 7-010, 7-013 to 7-015, 7-017, and 7-067 on the showing (AF 64L04-NE-0115).
In 1969, Gulf flew an airborne radiometric, magnetic and EM survey, completed VLF-EM and magnetic surveys over the Rabbit Lake grid and commenced zone drilling on the deposit. In 1970, Gulf performed geological mapping, geochemical and ground geophysical surveys over the deposit and continued the program of development drilling. In 1971, Gulf continued this program and started to prospect the deposit area. Development drilling continued into 1972.
Development of the deposit began in 1974. The deposit area was stripped and a bulk test ore sample was taken. In 1975, an airborne EM, magnetic and radiometric survey was flown over the area and the mill started to process ore (the average grade of the deposit was 0.45% U3O8). From 1976 to 1978, a reverse circulation deep overburden sampling program was performed in the mine area (64L04-0058).
From 1979 to 1981, Gulf Minerals Ltd. Completed a detail study of the Rabbit Lake Mine tailings pond area (AF 64L04-0098). 18 reverse circulation bore holes were completed to check subsurface groundwater conditions in the tailings pond area.
In October 1974, surface overburden stripping over the deposit commenced. Mining of the deposit commenced on 10 June 1975 and terminated in May of 1984 when ore was exhausted. The final Rabbit Lake ore was processed in October 1985. Peak annual production reached 2056 tonnes U from ore grading around 0.4% U3O8. Total production from the Rabbit Lake mine was 15,500 tonnes U grading 0.4% U from initially estimated reserves of 17,300 tonnes U. The open pit was turned into a depository for mill tailings from the remaining stockpiled Rabbit Lake ore and for the Collins Bay B Zone ore.
In April 1990, Cameco sold 33.3% of it's 100% ownership in the Rabbit Lake Mill to Uranerz Exploration.
Other Work Over The Area
Reverse circulation overburden drilling (64L04-0025;0049;0098); Rn222 in-water-survey and resampling (64L04-0009); airborne radiometric survey (64L04-0004); ground EM and magnetic surveys (64L04-0005); diamond drilling (64L04-0009;0096;0097); bulk ore trial (64L04-0012).
On 25 February 1999, Cameco staked the deposit as S-97901 within ML 5094.
The mill temporarily closed in June of 2001 when mining at Eagle Point ceased. The mine should open in the second quarter of 2002 to process Eagle Point ore. The mill will eventually process ore from Cigar Lake mine.
- Production History
- Production Period: 1987-01-01 to 1987-05-01
(open pit)
452,000.00 tonnes
Summary:
- Uranium: 2,590,000.00 kilograms @ 0.61 %
Production Period: 1986-01-01 to 1986-12-31
(open pit)
390,000.00 tonnes
Summary:
- Uranium: 1,447,000.00 kilograms @ 0.54 %
Production Period: 1985-01-01 to 1985-12-31
(open pit)
404,000.00 tonnes
Summary:
- Uranium: 972,000.00 kilograms @ 0.26 %
Production Period: 1984-01-01 to 1984-12-31
(open pit)
642,000.00 tonnes
Summary:
- Uranium: 1,605,000.00 kilograms @ 0.27 %
Production Period: 1983-01-01 to 1983-12-31
(open pit)
620,000.00 tonnes
Summary:
- Uranium: 1,467,000.00 kilograms @ 0.25 %
Production Period: 1982-01-01 to 1982-12-31
(open pit)
616,000.00 tonnes
Summary:
- Uranium: 1,427,000.00 kilograms @ 0.24 %
Production Period: 1981-01-01 to 1981-12-31
(open pit)
677,000.00 tonnes
Summary:
- Uranium: 1,423,000.00 kilograms @ 0.22 %
Production Period: 1980-01-01 to 1980-12-31
(open pit)
666,000.00 tonnes
Summary:
- Uranium: 2,320,000.00 kilograms @ 0.37 %
Production Period: 1979-01-01 to 1979-12-31
(open pit)
649,000.00 tonnes
Summary:
- Uranium: 2,435,000.00 kilograms @ 0.39 %
Production Period: 1978-01-01 to 1978-12-31
(open pit)
573,000.00 tonnes
Summary:
- Uranium: 2,494,000.00 kilograms @ 0.41 %
Production Period: 1977-01-01 to 1977-12-31
(open pit)
547,000.00 tonnes
Summary:
- Uranium: 2,287,000.00 kilograms @ 0.43 %
Production Period: 1976-01-01 to 1976-12-31
(open pit)
397,000.00 tonnes
Summary:
- Uranium: 1,691,000.00 kilograms @ 0.44 %
Production Period: 1975-06-10 to 1987-05-01
6,762,000.00 tonnes
Stripping of the deposit overburden commenced in 1974. Open pit mining of the deposit commenced on 10 June 1975 and terminated in May of 1984 when ore was exhausted. Total production from the mine was 15,500 tonnes U grading 0.4% U from a total estimated reserve of 17,300 tonnes U. The pit was converted to a tailings pond to hold the waste from processing stockpiled Rabbit Lake ore and Collins Bay deposits ore.
RABBIT LAKE MINE YEARLY PRODUCTION
YEAR TONNES ORE GRADE PRODUCTION
MILLED X 1000 % U3O8 KG U3O8 X 1000
________________________________________________
1975 129 0.31 329
1976 397 0.44 1,691
1977 547 0.43 2,287
1978 573 0.41 2,494
1979 649 0.39 2,435
1980 666 0.37 2,320
1981 677 0.22 1,423
1982 616 0.24 1,427
1983 620 0.25 1,467
1984 642 0.27 1,605
1985 404 0.26 972
1986 390 0.54 1,447
1987 452 0.61 2,590
________________________________________________
TOTAL 6,762 ---- 22,487
Summary:
- Uranium: 22,487,000.00 kilograms
Production Period: 1975-06-10 to 1975-12-31
(open pit)
129,000.00 tonnes
Summary:
- Uranium: 329,000.00 kilograms @ 0.31 %
- Reserves and/or Resources