Cosa Resources Corp. (CVE: COSA) (OTCMKTS: COSAF) (FSE: SSKU) has expanded several uranium exploration targets at its Murphy L0ake North project in Saskatchewan after completing a 13 hole summer drilling program.
Announced on Monday, the company drilled 6,752 metres across the Cyclone trend, testing geological structures over 650 metres of strike length. All 13 holes encountered moderate to strong alteration, significant geological structures or both across the targeted area. Additionally, several holes returned intervals of elevated radioactivity, although assay results remain pending for portions of the program.
Cosa operates Murphy Lake North and owns a 70 per cent interest in the project. Denison Mines Corp. (TSE: DML) (NYSE American: DNN) holds the remaining 30 per cent through the companies’ joint venture. The project sits three kilometres east of IsoEnergy’s Hurricane uranium deposit in Saskatchewan’s Athabasca Basin.
Summer drilling followed uranium mineralization encountered during Cosa’s winter 2026 program at the Cyclone trend. Hole MLN26-013 returned five metres averaging 0.55 per cent uranium oxide, or U3O8, from 308.5 to 313.5 metres depth. That interval included 0.5 metres averaging 1.70 per cent U3O8 from 310.5 to 311 metres. Consequently, Cosa expanded its summer testing 400 metres west and 250 metres east of MLN26-013.
The company primarily targeted the unconformity, where younger sandstone meets much older basement rocks beneath it. Uranium deposits in the Athabasca Basin can occur near this boundary or deeper within basement rocks. However, Cosa said considerable room remains to test potential basement hosted mineralization around the Cyclone trend during future programs.
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Assays received after summer drilling returned multiple metals
Drilling identified two prominent structures that Cosa calls the N-fault and S-fault along the Cyclone graphitic basement unit. The structures generally follow the northern and southern edges of that geological unit. The N-fault is considered the most prominent basement structure encountered at Murphy Lake North. Additionally, winter hole MLN26-017 encountered strong basement alteration associated with the structure.
Five summer holes targeted the N-fault where it approaches the unconformity. Those holes encountered moderate to strong alteration and faulting within sandstone, basement rocks or both. Some intervals contained hydrothermal hematite, an iron oxide alteration associated with hot, mineral rich fluids moving through rocks. Most of the holes encountered alteration and faulting above Cosa’s interpreted location of the S-fault as well.
Assay results from portions of the program remain pending and will help Cosa determine where to drill next. Meanwhile, the N-fault remains untested at the unconformity west of hole MLN26-028 and east of MLN26-025. Those gaps leave additional sections of the structure available for followup drilling during future exploration programs.
Cosa used holes MLN26-019 and MLN26-027 to target the S-fault where it meets the unconformity. Both holes passed beneath their intended targets and instead encountered the fault within deeper basement rocks. Consequently, the S-fault remains untested at the unconformity, while Cosa believes it joins the N-fault west of the 2026 drilling area.
Another hole, MLN26-020C1, followed strong basement alteration previously encountered by winter hole MLN26-017. Assays received after summer drilling began showed strong enrichment in nickel, cobalt and other uranium pathfinder elements around MLN26-017. Pathfinder elements can help explorers identify geological conditions associated with uranium without directly indicating an economically viable uranium deposit.
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Denison is Cosa’s largest shareholder
MLN26-020C1 extended that altered basement zone another 36 metres east of the previous intersection. Additionally, the hole encountered enrichment in a similar group of uranium pathfinder elements. The altered zone remains open down dip and down plunge from MLN26-017, providing Cosa with additional room for deeper testing.
Vice president of exploration Andy Carmichael said summer drilling changed Cosa’s understanding of the size of the altered area around Cyclone. The company now believes the winter mineralization sits within a substantially larger zone of geological alteration and structural disruption. Furthermore, Carmichael said the zone remains open for several hundred metres along strike in both directions.
Carmichael said every hole testing unconformity targets across the 650-metre area encountered geological structure, alteration or both. Several nearby targets have yet to be drilled. Cosa has already started planning an extensive follow up campaign at Murphy Lake North based on the new geological information.
President and CEO Keith Bodnarchuk said the summer campaign improved Cosa’s understanding of the geology surrounding the winter mineralization. He said the company intends to continue evaluating Cyclone and several other target areas across Murphy Lake North. Additionally, Cosa expects to return to the project for another drilling campaign in early 2027.
The company reported CAD$16 million in its treasury and said it can fund a significant follow up winter campaign. Cosa identified the altered basement zone around MLN26-017 and MLN26-020C1 among its immediate targets. It plans to test the S-fault and unexplored strike extensions along the N-fault during future drilling. Meanwhile, Denison remains Cosa’s joint venture partner at Murphy Lake North and its largest shareholder.
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Cosa’s winter campaign established uranium within the Cyclone trend
Cosa expects drilling to begin at its Darby and Aurora uranium projects in the coming days. Those programs should provide additional exploration results during the remainder of 2026. Subsequently, Cosa plans to shift its exploration focus back toward Murphy Lake North in early 2027.
Murphy Lake North covers part of the Larocque Lake trend, an established uranium exploration corridor in the Athabasca Basin. The trend hosts the Larocque Lake Zone, Yelka Prospect and Alligator Lake Zone. In addition, Murphy Lake North contains an extension of the basement geology underlying the nearby Hurricane deposit.
IsoEnergy Ltd. (NYSE American: ISOU) (TSE: ISO) owns Hurricane, located three kilometres west of Murphy Lake North. Cosa describes Hurricane as the world’s highest grade indicated uranium resource. Current members of Cosa’s exploration team previously helped discover and delineate the Hurricane deposit for IsoEnergy. Furthermore, Murphy Lake North contains both the Hurricane geological trend and the parallel Cyclone trend to its south.
Cosa’s winter program established uranium mineralization within the Cyclone trend before the larger summer campaign began. The winter drilling encountered several metres of basement hosted uranium within a broader area of strong structure and alteration. Additionally, the summer program expanded Cosa’s geological picture beyond that initial mineralized intersection and identified several areas requiring additional drilling.
The company will use pending assays and its updated geological interpretation to refine targets for the next Murphy Lake North campaign. Further drilling will focus on areas around the altered basement zone, the unresolved S-fault target and extensions of the N-fault. Cosa said its existing treasury leaves it funded for additional exploration drilling throughout 2027.
