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The Keefe Lake Property consists of 15,436 hectares and lies in northern Saskatchewan, approximately 280 km north of La Ronge. An access road passes within 15 km of the Property, with Provincial highway 905 running within approx. 30 km of the eastern claims border.
The first exploration of the Property consisted of regional reconnaissance programs in the 1970s, consisting of airborne and ground magnetic, radiometric and resistivity surveys, soil geochemistry and limited drillhole follow-up of geophysical targets. Thirteen drillholes were completed in 1979, the most notable of which are the four Eldorado DDH in Disposition S- 111008, drilled to follow up on ground IP and VLF targets, which returned anomalous 4 radiometric values from unconformity-proximal units and also encountered pegmatite dykes in the basement.
In 2007-08 Mega Uranium Ltd completed a heliborne time-domain resistivity and magnetic survey across the two northern dispositions, plus a 2D seismic reflection survey, consisting of 69 line km along 8 seismic lines. This work revealed an irregular topography on the unconformity surface, suggesting the presence of reactivated basement faults. Structural information from within the basement units was hinted at, such as an east-southeast dip for most of the basement units. Several of the basement structural trends picked from the seismic data correspond to magnetic anomalies (Hajnal 2009).
In 2011-12 Athabasca Uranium completed a nine-hole, 3,443.9 m drill program. Drillhole KEF-11-01A was terminated in a basement pegmatite which returned 137.5 ppm U over 2.12 m. This unit may correspond to a structure visible in the Mega Uranium seismic survey (McCallum & Nolde 2012). This interval is unconstrained given that it runs to the end of the hole. Pegmatites seen in the basement in other DDH generally returned elevated U (e.g. 94.5 ppm U over 1m in KEF-12-06; sample 53376). In KEF-12-08, the interval 380-412 m contained pegmatites and was interpreted to correspond to the U-mineralized zone at the end of KEF-11-01A. Core assays returned a high of 83.7 ppm U over 0.78 m (410.22- 411 m; sample 53429).
The Property lies near the southeastern margin of the Athabasca basin. In the Keefe Lake area, the Athabasca sediments are 120-190 m thick and sit atop a Paleoproterozoic belt of metasediments with a north-northeast strike and metamorphosed to amphibolite grade known as the Wollaston Domain. Elevated U values were revealed within, and proximal to, pegmatites within the Wollaston basement, as well as hematite altered breccia zones.
Known mineralization on the Property chiefly consists of basement-hosted uranium as outlined in the historic 2011/12 drill program. Downhole radiometric data may have revealed instances of basement (pegmatite) hosted uranium as well as unconformity-hosted uranium in the northeast of the Property (Ogryzlo 1981).
The style of deposit being explored for at Keefe Lake is the unconformity-type uranium deposit. In unconformity deposits, uranium mineralization has a close spatial association with reactivated Hudsonian faults in the basement underneath the Athabasca Basin. These faults often follow graphitic horizons within the Wollaston basement units. Uranium is theorized to have been leached from the Athabasca basin sequence and/or the basement units by oxidized, cold meteoric/hydrothermal fluids. The uranium thereby entrained was then reduced upon contact with this graphite, contained within the faults at the unconformity as well as adsorbed by the clay-rich regolith frequently developed above basement meta-pelite units. 5 Uranium is typically deposited in the form of uraninite/pitchblende. Some such deposits also contain appreciable base metals and other enrichments including Ni, Co, Zn and As. Unconformity deposits can be subdivided into “ingress” and “egress” deposits depending upon whether they lie below or above the unconformity surface. Basement-hosted “ingress” deposits can be found hundreds of metres deep into the basement beneath the unconformity (Powell et al 2007). It is possible that pegmatites or other basement units at Keefe Lake host uranium as part of the primary mineralogy or otherwise unrelated to Athabascan hydrothermal activity. Examples of this mineralization style include the Beaverlodge uranium camp northwest of the Athabasca Basin as well as the uranium-bearing pegmatites of the Bancroft area of Ontario.
In October 2021 Tisdale completed an IP survey at the Property. The survey consisted of a north-south-oriented grid totaling 3.0 line km with nine lines, situated in claim S111007 covering the area of basement pegmatite targets as seen in DDH KEF-11-01A, KEF-12-07 and KEF-12-08. The intent was to identify these pegmatites or any other basement structures of interest in order to clarify strike extensions, and intersections with other structures of interest. The survey suggested a relatively uniform picture of the subsurface with resistivity increasing with depth through the Athabasca sequence to the basement, and chargeability increasing sharply with depth then decreasing towards the basement unconformity. The chargeability data may suggest a lensing of more chargeable material within the Athabasca sediments in the centre of the survey area, and that this may represent a zone of clay alteration or an increase in disseminated sulphides.
Tisdale is currently considering a two-phase exploration program.
Phase 1 would consist of an IP survey to cover the Spitz and Snag target areas, totaling approximately 30 line km with an exact line configuration to be determined based on a review of topography and a prioritization of targets. This is to be followed by a thorough recompilation and review of all historic geophysical and geologic data, property-wide, and incorporating historic exploration on adjacent ground. This data review should be aimed towards producing an interpretation report outlining an enhanced geologic model with a series of targets selected for exploration.
Phase 2 would consist of a 1,500 m drill program intended to test the targets selected in Phase 1. These targets are likely to include extensions of the KEF-11-01A pegmatite at Keefe Lake itself, and the Spitz and Snag targets in the northeast, as well as structural targets as interpreted from the compilation work.