Patterson Lake South (PLS) Project

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Mine TypeUnderground
  • Uranium
  • Gold
Mining Method
  • Longitudinal retreat
  • Longhole stoping
  • Drift & Fill
Backfill type ... Lock
Mine Life... Lock
SnapshotThe Patterson Lake South (PLS) project hosts the Triple R deposit – the regions largest high-grade deposit at shallow depth and is accessible via all-weather Highway 955 which continues north through the area of the UEX-AREVA Shea Creek deposits to the past producing Cluff Lake uranium mine. Fission has published a Feasibility Study outlining the potential for the Triple R to become one of the lowest cost uranium mines in the world.

Dec. 13, 2023 Fission Uranium Corp. is pleased to announce the 2024 project development program, advancing towards construction and operation of a mine and mill for its PLS high-grade uranium project. The 2024 program will include submission of the Environmental Impact Assessment ("EIS"), resource expansion, ongoing community engagement, completion of the Front End Engineering and Design "FEED" phase, and the commencement of Detailed Engineering.


Fission Uranium Corp. (operator) 100 % Direct
The Patterson Lake South (PLS) Property is currently 100% owned by Fission Uranium Corp.



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Deposit type

  • Metamorphic hosted
  • Vein / narrow vein


The Triple R deposit is considered to be an example of a basement hosted vein-type or fracture-filled uranium deposit.

Appreciable high-grade mineralization is known to occur on the Patterson Lake South (PLS) Property in five zones, which collectively make up the Triple R deposit. From west to east, these zones are: 1) R1515W, 2) R840W, 3) R00E, 4) R780E, and 5) R1620E, the most significant of which is the R780E zone. Uranium mineralization discovered on the PLS Property to date is hosted primarily in basement lithologies with subordinate amounts intersected in the overlying Devonian sedimentary rocks. Mineralized zones occur within or near to the MSZ over a 3.17 km strike length along the PLG-3B EM conductor. The R1620E zone is currently defined by 23 drill holes and is located on the PLG-3C EM conductor, which is considered to be the eastern extension of the MSZ based on geology.

Uranium mineralization at the PLS Property is hosted primarily within metamorphosed basement lithologies and, to a much lesser extent, within overlying Meadow Lake Formation sedimentary rocks.

Mineralization within the Meadow Lake Formation sedimentary rocks typically occurs as fine grained disseminations, sooty blebs, and rarely semi-massive uranium mineralization. Uranium concentrations within the Meadow Lake Formation are generally low to moderate, however, grades greater than 1.00 wt% U3O8 have been intersected. When mineralized, the Meadow Lake Formation is typically strongly clay and chlorite altered, though locally can be pervasively hematite stained a deep red. Relative to basement hosted mineralization, only a very small amount of mineralized Meadow Lake Formation has been intersected on the PLS Property to date.

Basement hosted mineralization at the PLS Property occurs in a wide variety of styles, the most common of which appears to be fine grained disseminated and fracture filling uranium minerals strongly associated with hydrocarbon/carbonaceous matter within the MSZ. Uranium minerals, where visible, appear to be concordant with the regional foliation and dominant structural trends identified through oriented core and fence drilling (i.e., steeply dipping to the southeast). Typically, mineralization within the MSZ is associated with pervasive, strong, greygreen chlorite and clay alteration. The dominant clay species identified through PIMA analysis are kaolinite and magnesium-chlorite interpreted to be sudoite. The pervasive clay and chlorite alteration eliminates the primary mineralogy of the host rock with only a weakly defined remnant texture remaining. Locally, intense rusty limonite-hematite alteration in the orthogneisses strongly correlates with high grade uranium mineralization and a “rotten”, wormy texture.

Less common styles of uranium mineralization within the MSZ, which are often associated with very high grade uranium, include: semi-massive and hydrocarbon rich, intensely clay altered (kaolinite) with uranium-hydrocarbon buttons, and massive metallic mineralization. These zones of very high grade mineralization generally occur along the contact of the MSZ and intensely silicified QFBG-GN and comprise a high grade mineralized spine. This spine may represent a zone of intense structural disruption which has been completely overprinted by alteration and mineralization, however, drill holes that undercut the strongly mineralized spine have failed to show signs of significant structural damage. Particularly well mineralized drill holes are often associated with thin swarms of dravite-filled breccia.

Uranium mineralization within the north and south QFBG-GN which bound the MSZ generally occurs as fine grained disseminations and is almost always associated with pervasive whitish-green clay and chlorite alteration with local pervasive hematite. The mineralized zones within the QFBG-GN are interpreted to be stacked structures parallel to the MSZ strike and dip along the PLG-3B conductor.

Results of the detailed mineralogical work at the PLS Property indicate that the dominant uranium mineral present is uraninite, with subordinate amounts of coffinite, possible brannerite and U-Pb oxide/oxyhydroxide. Uranium minerals occur mainly as anhedral grains and polycrystalline aggregates with irregular terminations; irregularly developed veinlets, locally showing extremely complex intergrowths with silicates; micrometric inclusions and dendritic intergrowths with silicates; and very fine-grained dissemination intercalated with clays. In the samples studied, uranium minerals also occur as fine-grained inclusions in carbonaceous matter (hydrocarbon).

At R00E, uranium mineralization is generally found within several m of the top of bedrock which occurs at a depth of 50 m to 60 m vertically from surface. Several holes (e.g., PLS13-037, PLS13-039) drilled along the southern edge of the mineralization have intersected the down dip uraniferous root over 100 m below the top of bedrock. Uranium mineralization at R00E is hosted within the MSZ, northern QFBG-GN, and Meadow Lake Formation sediments. No uranium mineralization has been intersected to date in the silicified hanging wall or in the southern QFBG-GN.

R780E Zone
As with the R00E zone, R780E uranium mineralization has varying thickness, from tens of cm along the flanks to very wide intervals within the MSZ, as seen in PLS14-248 which intersected a lens of high-grade uranium mineralization over 15 m in true thickness. In section view, R780E mineralization generally occurs as sub-vertically and southeast dipping zones, concordant with the regional dip. A very high grade spine of uranium mineralization occurs within the main zone and has been traced as a series of lenses across almost the entire strike length of the R780E zone. The high-grade spine occurs adjacent to the contact between the MSZ and silicified QFBG-GN.

At the western R780E zone, uranium mineralization extends to near the top of bedrock. Moving eastward, the top of mineralization appears to be plunging at approximately -7° to the east. In general, the western R780E mineralization morphology is similar to the R00E, spatially restricted to the northern QFBG-GN, MSZ, and Meadow Lake Formation sediments. Moving eastward through the R780E zone, mineralization has been intersected within the MSZ, northern QFBG-GN, and Meadow Lake Formation sediments and, unlike the R00E zone, strong mineralization has been cored in the silicified QFBG-GN and southern QFBG-GN.

R1620E Zone
The R1620E zone is currently defined by 23 drill holes. Uranium mineralization at the R1620E occurs in what is interpreted to be the eastern extension of the MSZ and appears to be associated with the MSZ – silicified QFBGGN contact. The R1620E zone was last drilled during the winter 2017 program; additional drilling is recommended.

R840W Zone
The R840W zone is currently defined by 91 drill holes with a total grid east-west strike length of 425 m. Similar to the R00E and R780E zones, mineralization trends north-easterly in line with the MSZ. Additional drilling is recommended. Drill holes intersecting the near vertical mineralized zones at shallow angles or nearly parallel the mineralization do not reflect the true thickness of the fractures which range from 10 m to 20 m wide.

R1515W Zone
The R1515W zone is currently defined by 25 drill holes with the best mineralized intersection returned in PLS17-564 which cored 14.5 m of uranium mineralization averaging 3.39 wt% U3O8. Uranium mineralization at the R1515W occurs in the MSZ and appears to be associated with the MSZ – silicified QFBG-GN contact. The R1515W zone was last drilled during the winter 2018 program; additional drilling is recommended.



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All production numbers are expressed as yellow cake.

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* According to 2023 study.

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* According to 2023 study / presentation.

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UG mining costs ($/t milled) CAD 152.55 *  
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* According to 2023 study.

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