<p>Basement/sedimentary cover interfaces localize hydrothermal circulation, making them preferential areas for trapping and accumulating metals. Although these zones are well known for their potential to host mineralization, they have poor structural constraints. The Athabasca Basin (Saskatchewan, Canada) is a metallogenic province widely explored for Unconformity Related Uranium (URU) deposits. In this study, we focus on the basement/cover interface at five different sites located in the northeastern part of the basin, including unmineralized zones (Snake Lake, Pat Lake), small deposits (Waterfound, McClean South), and the giant Cigar Lake deposit. We combine drillcore logging and acoustic televiewer data to constrain the structural, mineralization and alteration patterns on both sides of the unconformity. Results show that the localization of clay alteration and uranium mineralization at the base of the basin and the top of the basement is mainly controlled by the brittle fracture network and lithological heterogeneities. Acoustic televiewer data show the presence of two main families of fractures: moderately to steeply dipping fractures (60°-80°) and fractures sub-parallel to the bedding (&lt; 20°). This second fracture set is most important in uranium mineralized areas and its expression correlates with the size of the uranium deposit. In the giant deposit, the fractures do not show a preferential orientation suggesting they are related to breccia formation. These findings support the development of a revised genetic model for URU-type deposits, in which the magnitude of the hydrothermal mineralizing event is governed by the intensity of fluid circulation and the associated overpressure, which drives uranium precipitation and orebody development.</p>