* In 2013, AREVA and UEX agreed to combine the Shea Creek Project and the contiguous Douglas River Project as the known mineralization at the northern boundary of Shea Creek extends into the Douglas River property. The combined projects are now referred to as the Shea Creek Project.
The Shea Creek property is currently the principal advanced exploration property in the western Athabasca Basin of northern Saskatchewan. The Shea Creek Project ("Shea Creek") is a joint venture between AREVA Resources Canada Inc. ("AREVA", 51% interest) and UEX Corporation ("UEX", 49% interest), with AREVA acting as project operator. Shea Creek hosts the Kianna, Anne, Colette and 58B deposits and is the most advanced of the eight Western Athabasca Projects from which UEX has earned a 49% interest from AREVA.
Shea Creek Deposits: Wireframe Model
Shea Creek is host to four uranium deposits which have recently estimated N.I. 43-101 mineral resources: Kianna, Anne, Colette and 58B. The current mineral resource estimate is supported by a technical report on the Shea Creek property, entitled "Technical Report on the Shea Creek Property, Saskatchewan, with an updated mineral resource estimate" (the "Shea Creek Technical Report") prepared by R. Sierd Eriks, P.Geo., James N. Gray, P.Geo., David A. Rhys, M.Sc., P.Geo., and Steve Hasegawa, P.Geo., with an effective date of May 31, 2013 filed on SEDAR at www.sedar.com
on May 31, 2013 and is posted on the UEX website here
The current mineral resource estimate for Shea Creek incorporates updated mineral resources for the Kianna, Anne and Colette deposits and for the first time a mineral resource estimate for the 58B Deposit located on the Shea Creek property. The estimate was based on drilling information up to December 31, 2012 and utilized results of 477 diamond drill holes (totaling 402,800 m) which were drilled since 1992.
At a cut-off grade of 0.30% U3
, Indicated mineral resources for the four Shea Creek deposits comprise 2,067,900 tonnes grading 1.48% U3
containing 67.66 million pounds of U3
, and an additional 1,272,000 tonnes grading 1.01% U3
in the Inferred category containing 28.19 million pounds of U3
This estimate confirms Shea Creek as the largest undeveloped uranium resource in the Athabasca Basin (the "Basin"). It also ranks as the third largest uranium resource in the Basin, exceeded in size only by McArthur River and Cigar Lake. Mineral resources at Shea Creek are still largely open and have excellent potential to expand significantly as drilling continues.
Shea Creek mineral resource estimates at various cut-off grades are summarized below. Significantly, at higher cut-off grades most of the contained uranium is retained at substantially higher grades.
Shea Creek Mineral Resource Estimates, Tonnes and Grade at Various U3O8 % Cut-offsThese mineral resource estimates were completed in April 2013 (incorporating drilling information up to December 31, 2012)
using CIM standards of estimation of mineral resources.
These mineral resource estimates were calculated using a minimum cut-off grade of 0.05% U3
utilizing a geostatistical block-model technique with ordinary kriging methods and the Gemcom software package.
The majority of the estimated mineral resources are from the Kianna and Anne deposits, where a significant portion of the resources lie in basement rocks beneath the Athabasca unconformity. A breakdown of mineral resource estimates by deposit at a cut-off grade of 0.30% U3
is provided below:
Breakdown of the Contribution of Each Deposit at Shea Creek to the Total Mineral Resource Estimates
at a 0.3% U3O8 Cut-off
These mineral resource estimates were calculated using a minimum cut-off grade of 0.05% U3
utilizing a geostatistical block-model technique with ordinary kriging methods and the Gemcom software package.
Drilling on the northern Shea Creek property has resulted in the intersection of numerous significant areas of uranium mineralization associated with the three-kilometre corridor hosting the Anne, Kianna, Colette and 58B deposits.
Due to the greater than 600-metre depths to the target area, drilling is generally conducted by penetrating overburden with HW-diameter casing followed by HQ coring to 400 metres depth. The holes are typically completed by reducing to NQ-sized core (47.6 mm core diameter) which is the typical core size for testing mineralization at target depths.
Directional drilling, first introduced in the Athabasca Basin by AREVA in 1999, is utilized at Shea Creek. This technology, which uses a steerable drill bit to allow several target intersections to be completed from one master (pilot) hole, reduces the cost while improving targeting precision when drilling deep targets. A pilot hole is strategically positioned within a target area and subsequent directional cuts from the pilot hole are made towards specific targets. For example, a vertical pilot hole may reach the unconformity at a depth of 700 metres and continue into the basement for another 150 metres. Directional drilling from that pilot hole could begin in the sandstone at the 400-metre level, angling in a new direction to a different unconformity impact location and beyond, thus saving the time and expense of 're-drilling' the 400-metre length to the point where the directional hole begins.
As a result, a unique nomenclature is used for the Shea Creek drill holes. For example, "SHE-109" refers to a vertical pilot hole, with subsequent directional cuts from that pilot hole numbered "SHE-109-1", "SHE-109-2", etc.
The Kianna, Anne, Colette and 58B deposits within Shea Creek are distributed along a strike length of over three kilometres of the north-northwest-trending 33-kilometre-long Saskatoon Lake graphitic conductor. The Saskatoon Lake Conductor is coincident with a southwest-dipping reverse fault that displaces the flat-lying unconformity with the overlying Athabasca Group sandstone by several tens of metres. Depths to the unconformity typically range from 700 to 740 metres.
Drill holes generally have dips of 75° or steeper which generally cross the flat-lying lenses of unconformity-hosted and perched mineralization styles at a high angle that is close to, or at, true thickness. Mineralized intercepts of discordant basement mineralization have more complex morphology, and in most cases the true thickness of intercepts are as yet undetermined although these discordant basement zones can contain combinations of steeply dipping vein-like mineralization which occur at shallow core axis angles to many drill holes, in combination with foliation parallel, shallower dipping components which may form oreshoots.
As is standard practice in uranium exploration, downhole radiometric (gamma) geophysical probing surveys are performed from the bottom of the hole up through the drill string at the completion of each drill hole. Some of the uranium grades reported on this website for Shea Creek are calculated from gamma probe logging. The probe results are reported as uranium equivalent (eU3
). Equivalent grade results are obtained using a DHT27-STD gamma probe which collects continuous readings along the length of the drill hole. Probe results are calibrated using an algorithm calculated from the comparison of probe results against geochemical analyses in previous drill holes in the Shea Creek area.
Kianna Deposit - Results to May 31, 2013
Kianna Deposit: Wireframe Model
The Kianna Deposit contains stacked perched (P), unconformity (UC) and basement (B) mineralization which lie in an east-northeast-trending corridor corresponding with a large zone of basement clay alteration.
The perched mineralization in the Kianna Deposit forms at least two pods above the higher grade areas of unconformity-hosted mineralization, at distances of 20 to 70 metres above the unconformity. One high-grade pod, which has plan view dimensions of approximately 60 by 30 metres, contains intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
or 1.0% eU3
) that are at close to true thickness which include:
- (P) 20.721% eU3O8 over 10.2 m, including 27.729% eU3O8 over 7.6 m in hole SHE-114-05;
- (P) 7.367% U3O8 over 9.5 m, including 10.700% U3O8 over 6.5 m in hole SHE-114-07;
- (P) 4.637% eU3O8 over 22.2 m, including 8.001% eU3O8 over 3.2 m and 7.851% eU3O8 over 8.8 m in hole SHE-114-09;
- (P) 4.580% eU3O8 over 15.3 m, including 9.967% eU3O8 over 6.4 m in hole SHE-114-11;
- (P) 3.859% eU3O8 over 14.2 m, including 20.629% eU3O8 over 1.4 m in hole SHE-114-18A;
- (P) 5.939% eU3O8 over 12.0 m, including 23.145% eU3O8 over 2.7 m in hole SHE-114-19;
- (P) 2.709% eU3O8 over 14.2 m, including 12.406% eU3O8 over 1.0 m in hole SHE-114-19A;
- (P) 6.165% U3O8 over 6.7 m, including 20.134% U3O8 over 2.0 m in hole SHE-115-08; and
- (P) 8.420% eU3O8 over 12.6 m in hole SHE-115-18.
Beneath the perched mineralization, unconformity mineralization at Kianna forms a high-grade lens that lies above the basement mineralization. Drilling between Kianna and Anne has established that mineralization at the unconformity is continuous between the deposits, indicating a strike length of at least 1,000 metres which is open in all directions. Significant intercepts at Kianna (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
), which are close to true thickness, occur over a 70 metre (north-south) by 150 metre (east-west) area and include:
Basement Mineralization - Main Zone
- (UC) 9.335% U3O8 over 12.2 m, including 21.154% U3O8 over 4.3 m in hole SHE-115-03;
- (UC) 2.547% U3O8 over 19.0 m, including 5.847% U3O8 over 7.0 m in hole SHE-115-04;
- (UC) 7.827% U3O8 over 7.2 m, including 20.360% U3O8 over 2.7 m in hole SHE-115-05;
- (UC) 2.227% U3O8 over 10.6 m, including 7.263% U3O8 over 1.5 m in hole SHE-115-06;
- (UC) 6.297% U3O8 over 7.9 m, including 9.394% U3O8 over 4.9 m in hole SHE-118;
- (UC) 2.275% U3O8 over 11.5 m, including 5.011% U3O8 over 4.3 m in hole SHE-118-09;
- (UC) 2.582% U3O8 over 6.4 m in hole SHE-118-18;
- (UC) 11.767% U3O8 over 3.8 m, including 21.883% U3O8 over 2.0 m in hole SHE-118-19;
- (UC) 1.586% U3O8 over 8.5 m, including 10.060% U3O8 over 1.0 m in hole SHE-135-01; and
- (UC) 1.625% U3O8 over 9.5 m in hole SHE-135-05.
The most significant extensive mineralization at Kianna occurs in an east-northeast-trending zone of basement-hosted mineralization which extends to at least 200 metres below the unconformity and has a strike length of approximately 180 metres as defined to date. Significant intercepts in this zone (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
or 1.0% eU3
) are listed below. The true thickness of many of these intercepts is unknown; some are drilled at shallow angles to mineralization.
Basement Mineralization - Kianna North Zone
- (B) 3.578% U3O8 over 11.8 m and 5.776% U3O8 over 6.5 m in hole SHE-114-08;
- (B) 4.093% U3O8 over 45.0 m, including 18.073% U3O8 over 6.0 m in hole SHE-114-11;
- (B) 4.382% U3O8 over 7.8 m, including 20.023% U3O8 over 1.5 m in hole SHE-114-17;
- (B) 2.600% U3O8 over 4.2 m, including 10.551% U3O88 over 1.0 m in hole SHE-114-18A;
- (B) 3.727% eU3O8 over 10.8 m, including 5.035% eU3O8 over 5.4 m in hole SHE-114-19A;
- (B) 1.020% eU3O8 over 141.4 m, including 2.720% eU3O8 over 6.6 m, 5.553% eU3O8 over 15.8 m and 2.391% eU3O8 over 5.3 m in hole SHE 114-20;
- (B) 6.268% U3O8 over 3.5 m, including 40.086% U3O8 over 0.5 m in hole SHE-115-01;
- (B) 3.643% U3O8 over 4.5 m, including 30.418% U3O8 over 0.5 m in hole SHE-115-05;
- (B) 1.059% U3O8 over 15.0 m and 2.206% U3O8 over 7.5 m in hole SHE-115-08;
- (B) 1.840% U3O8 over 22.0 m, including 15.193% U3O8 over 1.5 m in hole SHE-115-09;
- (B) 8.581% U3O8 over 15.0 m, including 24.346% U3O8 over 2.5 m in hole SHE-115-10;
- (B) 3.731% U3O8 over 10.0 m, including 22.322% U3O8 over 1.5 m in hole SHE-115-15A;
- (B) 2.188% U3O8 over 9.5 m, including 7.951% U3O8 over 2.5 m in hole SHE-118-08;
- (B) 19.244% U3O8 over 1.0 m in hole SHE-118-15;
- (B) 1.553% U3O8 over 34.3 m, including 1.543% U3O8 over 8.8 m and 2.359% U3O8 over 16.2 m in hole SHE-135-04;
- (B) 2.250% U3O8 over 5.0 m in hole SHE-135-07; and
- (B) 1.190% U3O8 over 9.5 m in hole SHE-135-08.
The Kianna North area, also referred to as the GAMP Zone, includes a zone of mineralization which lies in the northwestern portion of the Kianna Deposit and was initially intersected in 2010. During that program, drill hole SHE-136-01 intersected 1.697% U3
over 17.0 metres approximately 50 metres to the north of the main Kianna basement zone. Subsequent drilling of the SHE-130 series drill holes in 2011 outlined a new zone of basement mineralization which lies north of the main Kianna basement deposit. Intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 0.6% U3
- (B) 1.293% U3O8 over 22.0 m, including 2.164% U3O8 over 11.0 m in hole SHE-130-04;
- (B) 0.602% U3O8 over 23.8 m, including 1.137% U3O8 over 11.5 m in hole SHE-130-11; and
- (B) 0.612% U3O8 over 31.5 m in hole SHE-130-12.
Geologically, these intercepts occur in a south to southeast-dipping zone of mineralization (see following figure) which was incorporated into the 2013 updated mineral resource estimate and is still open to the east. Additional mineralized intercepts, which lie outside of this resource, define further prospective targets for similar mineralization styles.
Wireframe model of Kianna North basement mineralization (in green) showing 2011 drill holes of the SHE-130 series and the position of the new zone of mineralization in relation to the main Kianna basement zone (in blue).
Basement Mineralization - Kianna East Zone
Significant mineralization was intersected in the Kianna East Zone during 2012. The Kianna East Zone is a newly discovered southwest-dipping zone of concordant mineralization which lies approximately 80 to 110 metres below and east of the main Kianna basement zone and about 200 metres below the unconformity. Given the orientation of the drill holes, the Kianna East intercepts may lie at or close to true thickness. Significant intercepts obtained in the Kianna East Zone during 2012, which were incorporated into the recent 2013 updated mineral resource estimate, include the following results (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
- (B) 1.949% U3O8 over 20.0 m, including 5.662% U3O8 over 3.0 m and 7.447% U3O8 over 2.9 m in hole
- (B) 3.876% U3O8 over 15.0 m, including 8.710% U3O8 over 6.1 m in hole SHE-135-11;
- (B) 2.361% U3O8 over 7.0 m, including 4.058% U3O8 over 3.5 m in hole SHE-135-12;
- (B) 3.299% U3O8 over 19.1 m, including 13.403% U3O8 over 3.7 m in hole SHE-135-13; and
- (B) 1.695% U3O8 over 7.0 m, including 5.458% U3O8 over 2.0 m in hole SHE-135-14.
This high-grade zone occurs parallel to and along the top of a southwest-dipping graphitic unit which forms an electromagnetic (EM) anomaly to the east of, and parallel to, the Saskatoon Lake Conductor. The new zone is open to the northwest, southeast and up dip to the northeast. Future drilling will test for the potential of the new basement zone to continue along strike and to extend upward along the graphitic unit toward the unconformity.
Wireframe model of Kianna East basement mineralization (in yellow and orange) showing 2012 drill holes of the SHE-118 and SHE-135 series.
Anne Deposit - Results to May 31, 2013
Anne Deposit: Wireframe Model
Mineralization in the Anne Deposit has been traced continuously over a strike length of approximately 500 metres. Some of the more significant drilling intercepts at Anne occur in areas of mineralization which straddle the unconformity and extend downward continuously into the underlying basement, forming broad areas of basement mineralization beneath. A significant zone of mineralization of this style, which occurs in the north-central portions of the deposit, includes the following intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
) which are largely basement hosted:
- 4.411% U3O8 over 14.9 m, including 20.898% U3O8 over 2.9 m in hole SHE-095-03;
- 5.419% U3O8 over 19.0 m, including 29.200% U3O8 over 3.4 m in hole SHE-096-03;
- 3.315% U3O8 over 25.1 m, including 16.866% U3O8 over 4.0 m in hole SHE-100-01;
- 3.951% U3O8 over 9.0 m in hole SHE-109-06;
- 4.206% U3O8 over 36.0 m, including 13.703% U3O8 over 6.5 m and 3.512% U3O8 over 8.5 m in hole
- 3.642% U3O8 over 20.5 m, including 11.407% U3O8 over 6.0 m in hole SHE-122-05.
Other significant mineralized intercepts at Anne are more clearly basement (B) or unconformity (UC) hosted. Best intercepts occur in two areas, the first as part of the zone of mineralization represented by the intercepts mentioned above, and a second area in south-central portions of the deposit. Basement mineralization in southern parts of the Anne Deposit is mainly of the concordant basement style, while in the north mineralization represents a combination of the concordant and discordant styles for which true thickness is generally undetermined. Significant intercepts in these higher grade areas that are generally at, or close to, true thickness, include the following (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
Colette Deposit - Results to May 31, 2013
- (UC) 11.607% U3O8 over 6.0 m, including 23.964% U3O8 over 2.9 m which includes 34.694% U3O8 over
1.9 m in hole SHE-087;
- (UC) 10.027% U3O8 over 8.4 m, including 34.149% U3O8 over 2.3 m which includes 60.601% U3O8 over
1.2 m in hole SHE-099;
- (UC) 5.649% U3O8 over 17.9 m, including 14.547% U3O8 over 6.5 m in hole SHE-099-02;
- (UC) 8.282% U3O8 over 7.4 m, including 17.075% U3O8 over 2.0 m in hole SHE-109-05;
- (UC) 1.518% U3O8 over 7.6 m in hole SHE 131-03;
- (B) 3.244% U3O8 over 9.0 m, including 10.159% U3O8 over 2.0 m in hole SHE-088;
- (B) 4.553% U3O8 over 3.9 m, including 7.925% U3O8 over 2.2 m in hole SHE-094-01;
- (B) 5.740% U3O8 over 2.8 m, including 14.089% U3O8 over 0.9 m in hole SHE-094-06;
- (B) 1.044% U3O8 over 19.8 m in hole SHE-095-03;
- (B) 3.639% U3O8 over 7.5 m, including 16.954% U3O8 over 0.6 m in hole SHE-100-01;
- (B) 1.854% U3O8 over 11.1 m in hole SHE-109-05; and
- (B) 3.569% U3O8 over 4.0 m, including 6.661% U3O8 over 1.5 m in hole SHE-122-04.
Colette Deposit: Wireframe Model
The northwestern portions of the prospective corridor at Shea Creek contain the Colette Deposit. Colette contains two components: unconformity-hosted (UC) mineralization distributed over a 500-metre strike length, and at its southeastern end, stacked concordant zones of basement (B) mineralization along a 250-metre strike length which have recently been identified and are largely open downdip.
Similar to other parts of Shea Creek, the best intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
) at the unconformity lie in two east-northeast-trending corridors at the southeastern and northwestern ends of the Colette Deposit associated with discordant faults, and include:
- (UC) 1.432% U3O8 over 12.2 m, including 2.916% U3O8 over 5.6 m in hole SHE-045;
- (UC) 2.342% U3O8 over 16.8 m, including 4.294% U3O8 over 7.8 m which includes 7.547% U3O8 over 2.7 m in hole SHE-052;
- (UC) 4.099% U3O8 over 6.6 m, including 6.493% U3O8 over 3.9 m in hole SHE-059;
- (UC) 1.732% U3O8 over 11.9 m, including 3.476% U3O8 over 4.6 m in hole SHE-065;
- (UC) 1.122% U3O8 over 11.0 m in hole SHE-078; and
- (UC) 1.517% U3O8 over 8.9 m in hole SHE-091.
Recent drilling in 2011 and 2012 at the northern end of the Colette Deposit in the SHE-066 series holes has expanded the unconformity mineralization northward. Drill intersections from these holes have been incorporated into the recent 2013 updated mineral resource estimate. Mineralization intersected in these drill holes straddles the unconformity extending for over 25 metres above the unconformity. Significant intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 0.5% U3
or 1.0% eU3
) are as follows:
- (UC) 1.058% U3O8 over 18.7 m, including 1.518% U3O8 over 7.4 m in hole SHE-066-02;
- (UC) 1.218% eU3O8 over 27.9 m, including 1.409% eU3O8 over 10.3 m in hole SHE-066-03;
- (UC) 0.625% U3O8 over 19.0 m in hole SHE-066-04; and
- (UC) 1.720% U3O8 over 10.5 m in hole SHE-066-10.
These drill holes continue to define a thick flat-lying lens of mineralization at the unconformity which, on the basis of its overall morphology, suggests that the new intercepts are within 90% of true thickness.
Significant basement intercepts (with a grade-thickness product of greater than 2.0 and grades of greater than 0.5% U3
or 0.5% eU3
) in the southern area of dominantly concordant basement mineralization include:
58B Deposit - Results to May 31, 2013
- (B) 0.907% eU3O8 over 10.8 m, including 3.91% eU3O8 over 1.2 m in hole SHE-111-02;
- (B) 0.582% eU3O8 over 16.2 m and 2.458% U3O8 over 1.0 m in hole SHE-111-05;
- (B) 3.227% U3O8 over 8.0 m, including 12.380% U3O8 over 0.5 m and 23.934% U3O8 over 0.5 m in hole SHE-111-06;
- (B) 0.633% U3O8 over 4.5 m in hole SHE-111-11;
- (B) 0.879% U3O8 over 11.5 m, including 4.810% U3O8 over 1.0 m in hole SHE-111-12; and
- (B) 0.855% U3O8 over 7.5 m, including 4.047% U3O8 over 1.5 m in hole SHE-139-01.
58 Deposit: Wireframe Model
58B is a new deposit which lies between the Kianna and Colette deposits along a one-kilometre strike length of the Shea Creek trend. The 2013 mineral resource estimate for Shea Creek includes for the first time a mineral resource for the 58B Deposit. The area had previously been tested by only very widely spaced holes. In 2009, one new pilot hole and two directional cuts were completed to test the possible continuity of mineralization intersected by discovery hole SHE-58B drilled in 1997, which encountered unconformity mineralization grading 0.476% eU3
over 8.8 metres and multiple mineralized intervals in the basement including 2.213% U3
over 2.6 metres. Drilling in 2009 intersected similar styles of structurally controlled, vein-hosted mineralization in the basement, including 1.917% U3
over 3.5 metres and 0.998% U3
over 1.0 metre in drill hole SHE-133-02.
Drilling results in 2010 from directional cuts off pilot holes SHE-133 and SHE-104, along with previous results reported from historical holes, have outlined continuous unconformity mineralization over a northwesterly strike length of 400 metres and a lateral width of up to 110 metres in plan view. Significant unconformity intercepts (with a grade-thickness product of greater than 10.0 and grades of greater than 1.0% U3
), which are close to true thickness, include:
- (UC) 2.261% U3O8 over 7.5 m, including 3.668% U3O8 over 4.2 m in hole SHE-133-03;
- (UC) 5.043% U3O8 over 2.4 m in hole SHE-133-04; and
- (UC) 1.898% U3O8 over 10.4 m in hole SHE-133-07.
A significant aspect of the current and previously reported basement intercepts in the 58B Deposit is that many occur in a set of east-northeast-trending, steeply dipping pitchblende veins which drilling has intersected to a depth of at least 100 metres below the Athabasca unconformity. This mineralization style and orientation at 58B are comparable to the Kianna Deposit basement mineralization, which forms a large part of the overall Shea Creek resource, and which itself is still open. Significant intercepts (with a grade-thickness product of greater than 5.0 and grades of greater than 1.0% U3
) in the basement of the 58B Deposit are listed below. The true thickness of many of these intercepts is unknown.
- (B) 2.213% U3O8 over 2.6 m in hole SHE-058B;
- (B) 1.917% U3O8 over 3.5 m, including 10.300% U3O8 over 0.5 m in hole SHE-133-02;
- (B) 9.514% U3O8 over 0.8 m, including 19.000% U3O8 over 0.4 m in hole SHE-133-03; and
- (B) 8.097% U3O8 over 1.5 m in hole SHE-133-06.
The Shea Creek deposits are typically stacked, with basement mineralization often occurring directly beneath significant zones of mineralization at the unconformity and locally developed zones of perched mineralization which may occur in the overlying sandstone above the unconformity. In the 58B Deposit, drill hole SHE-133-08 also intersected a low-grade interval of perched mineralization grading 0.095% U3
over 4.5 metres in chloritic breccia 11 to 16 metres above the unconformity. This suggests potential for this mineralization style at 58B, and which at Kianna is host to very high-grade mineralization.
The presence of all three styles of mineralization (basement, unconformity and perched) in the 58B Deposit is encouraging, and is typical of the Kianna, Anne and Colette Deposits. Overall style of mineralization and the open nature of the mineralization particularly in the basement at 58B suggest the potential for additional mineralization here and in the intervening areas between Kianna and Colette.
Uranium Mineralization Photos
Gold was mined as a by-product from the D orebody at Cluff Lake. At Shea Creek, locally high gold grades are also present. The high gold grades frequently, but not always, occur in areas of higher-grade uranium mineralization, and are known to be present both in unconformity and basement mineralization in three of the four deposits at Shea Creek. Native gold grains both encapsulated in pitchblende, sometimes in association with Bi-tellurides, and free in the surrounding clay alteration have been identified in samples from basement- and sandstone-hosted mineralization. Significant composited gold-bearing intercepts include:
- SHE-079: 13.75 g/Tonne Au over 2.50 m;
- SHE-115-03: 14.02 g/Tonne Au over 3.30 m;
- SHE-087: 20.79 g/Tonne Au over 2.40 m;
- SHE-102: 9.70 g/Tonne Au over 3.50 m; and
- SHE-115-04: 5.95 g/Tonne Au over 5.70 m.
Gold analyses are by fire assay at the SRC Laboratories. The true thickness and morphology of areas of higher-grade gold mineralization are as yet undetermined.
Future work to establish patterns of gold distribution is planned, especially to identify if any consistent local gold-enriched domains can be identified which might enhance the value of parts of the Shea Creek deposits.
Uranium mineralization on the Shea Creek property is of the unconformity-associated uranium deposit type, which is spatially related to the sub-Athabasca unconformity in the region. These are generally interpreted to result from interaction of oxidized diagenetic-hydrothermal fluids with reduced basement rocks and/or with reduced hydrothermal fluids along faults extending upward toward the unconformity in the underlying basement below.
Uranium mineralization identified to date on the Shea Creek property lies in northernmost portions of the property, comprising the Kianna, Anne, Colette and 58B deposits and intervening mineralization between the deposits. These deposits occur along an approximately three-kilometre strike length of the north-northwest-trending pelitic gneiss unit that is host to the 33-kilometre-long Saskatoon Lake Conductor. The deposits occur at depths of 650 to 800 metres below current surface and beneath the thick sequence of overlying Athabasca Group sandstone.
The partial definition of 58B in 2010 highlighted the significant exploration potential of the Shea Creek mineralization trend along the Saskatoon Lake Conductor. The 700-metre strike length between Kianna and 58B remains sparsely tested, particularly along a 400-metre strike extent of this corridor. Elsewhere on the property, drilling is limited and widely spaced with mineralization open in almost every direction. Large parts of the Saskatoon Lake Conductor remain untested and the potential for resource expansion at Shea Creek is extremely high.
Three styles of mineralization are developed within these mineralized domains, based on their position with respect to the Athabasca unconformity, and overall morphology. They comprise:
- Unconformity-hosted uranium mineralization
This is the most widespread style of mineralization identified to date. It forms shallow-dipping zones that are developed in the lowermost Athabasca sandstone immediately above the sub-Athabasca unconformity, or straddling the unconformity and extending downward for several metres into the underlying basement gneisses. The mineralization typically is elongate in plan view, occurring at the unconformity over a 40 to 150 metre lateral width along the trace of the northeastern margins of the pelitic gneiss unit where it intersects the unconformity, and extending over parts of the footwall granitic gneiss. Drilling between Kianna and Anne has established that mineralization at the unconformity is continuous between the deposits, indicating a strike length of at least 1,000 metres which is open in all directions. Mineralization in high grade areas may comprise massive, nodular or blebby pitchblende +/- coffinite +/- yellow uranium-silicates in a hematite-clay matrix. In lower grade areas, unconformity-hosted mineralization may be disseminated in chlorite-clay-dravite alteration. The mineralization of all grades is often associated with, and occurs within, chlorite-dravite dissolution breccias in the basal sandstone.
- Basement-hosted mineralization
This is the second most extensive style of mineralization, occurring in several portions of the Anne Deposit, in a large zone at Kianna, in the Colette South area and in parts of the 58B Deposit. Basement-hosted mineralization is developed mainly in granitic gneiss up to 200 metres below the sub-Athabasca unconformity, and immediately beneath, and up to 180 metres below, the pelitic gneiss unit and associated R3 faults. The mineralization is variable in style and morphology, and is associated with areas of intense white to pale green clay-chlorite alteration. Basement mineralization can be either concordant or discordant in style, with the two styles often occurring together or branching off one another.
Concordant basement mineralization, which occurs in the southern Anne and South Colette deposit areas and parts of Kianna, forms dominantly shallow to moderate west-southwest lenticular zones that are parallel or subparallel to gneissosity in the granitic gneiss. This mineralization style may form stacked zones that are separated from, or splay off, unconformity-hosted mineralization, and which often follow southwest-dipping fault surfaces or lithologic units. Where present, a garnet-amphibolite gneiss ("metabasite") subunit may be preferentially mineralized, the most notable example of which forms a significant pod of mineralization north of the main Kianna basement zone (GAMP Zone). The Kianna East Zone represents a concordant basement mineralization style which lies along the upper contact of a deep graphitic unit that is parallel to the Saskatoon Lake Conductor.
Discordant basement mineralization, which is best developed in the main Kianna basement zone and in the northern Anne Deposit, is defined by steeply-dipping, easterly-trending mineralized zones of disseminated, nodular and locally massive replacement style pitchblende +/- coffinite +/- hematite +/- uranium silicates, and by sets of pitchblende +/- quartz +/- clay veinlets. Core reorientation suggests that the veinlets trend east-northeast with moderate to steep northerly dips parallel to the discordant zones. Interaction between concordant and discordant mineralization styles forms oreshoots within basement mineralization that plunge moderately to shallowly to the west-southwest.
- Perched mineralization
This is the least voluminous of the three mineralization styles. It comprises flat-lying to shallow southwest-dipping lenses of disseminated to massive pitchblende-coffinite-hematite-clay mineralization that are developed in Athabasca sandstone up to 60 metres above the sub-Athabasca unconformity. Perched lenses may occur stacked above unconformity mineralization with no associated faulting, or may occur along, or at the termination of, southwest-dipping faults where they project upward into the Athabasca sandstone from pelitic gneiss below.
Where best-developed and of the highest grade, all three mineralization styles may be vertically stacked on top of one another. These stacked, better-developed areas of mineralization may be localized in areas where steeply dipping, discordant east-west to northeast-trending faults interact with, and intersect, the foliation-parallel faults at the unconformity, creating zones of high dilatancy and structural permeability. Pre-Athabasca basement structural architecture may play an important role in localizing these higher grade areas. In areas where the Saskatoon Lake Conductor is offset by northeast-trending dextral mylonitic shear zones, faults localized along the conductor may step and splay as they link across the area of offset. In addition, the older shear zones may be remobilized and host, or control, adjacent mineralization. Basement mineralized zones may be mantled by sheeted sets of quartz and quartz-dravite veins, although pre-mineralization veins associated with mylonites are also evident.
Mineralization is associated with extensive clay alteration which affects the lower sandstone and extends downward into the basement rocks. Principal clay minerals are illite, chlorite, kaolinite and dravite. An early phase of illitization is commonly evident, while kaolinite is generally paragenetically late. Extensive areas of chlorite-clay-dravite matrix breccias occur along the unconformity in the basal sandstone column, and are spatially associated with unconformity-hosted mineralization. The presence of pitchblende fragments in breccia and the overprinting of the breccia matrix by pitchblende-coffinite assemblages indicate a syn-mineralization timing which was probably also coeval with reverse faulting along the R3 structures. In basement rocks, clay alteration envelops mineralized zones and outlines their general morphology. Modeling of clay alteration therefore forms an important targeting tool. An extensive northeast-trending and steeply dipping clay alteration zone at Kianna is open to the east and west and contains unbounded mineralization to the north, providing significant room for the expansion of Kianna basement mineralization, and the potential for additional parallel basement zones.