The Overstall occurrence is located on a south-flowing tributary of Menard Creek approximately 156 kilometres north-northwest of the community of Germansen Landing.

The regional and local geology is similar to that of the ARD occurrence (MINFILE 094D 090) located 1.8 kilometres south.

Locally, the area is cut by a north-trending fault that separates andesitic rocks of the Upper Triassic Savage Mountain Formation (Takla Group) to the west from an undifferentiated package of Upper Triassic volcanics (Takla Group) to the east. Both volcanic packages are represented by aphanitic to porphyritic (feldspar) andesites. The undifferentiated volcanics are cut by a medium-grained gabbro with phenocrysts of plagioclase feldspar and pyroxene. The gabbro may be part of Upper Triassic ultramafic rocks that occur nearby.

The Savage Mountain volcanics are cut by northwest trending pink porphyritic granodiorite dikes. These dikes contain hornblende and plagioclase phenocrysts in a matrix of quartz, plagioclase and orthoclase. Close to the faults, the matrix is chlorite altered. The dikes terminate against the north-trending fault. A 60-metre pyritic and propylitic envelope exists on either side of the fault. A serpentinite-altered zone is developed around the gabbro intrusion and is more pervasive near the fault. This serpentinization overlaps onto both sides of the fault and is fairly widespread near the mafic intrusion.

Mineralization consists of chalcopyrite in pyritic shears near the margin of a granodiorite dike.

Work History

In 1973, Denison Mines Ltd. completed a program of geological mapping, soil sampling and a 21.0-line-kilometre ground magnetic survey on the area Ard claim group.

In 2015, High Power Exploration conducted property wide, broadly spaced geochemical sampling and reconnaissance style mapping and prospecting on key target areas on their large Menard property which covers eight occurrences (ARD, 094D 090); Kim, 094D 174; Overstall (this description); Verna, 094D 173; Menard Pass, 094D 049; Garry, 094D 175; Nightfly, 094D 155; and Nikos, 094D 085. A total of 10 days field work were completed and included the collection of 78 stream silt sediment samples of first and second order creeks across the property, the collection of 202 “B” horizon samples on topographic contour lines on approximately 100 metre-spaced samples in areas with outcrop or thin cover, and the collection of 294 "Ah" horizon soil samples on topographic contour lines with 100 metre-spaced samples in areas with thick till cover. Several recorded MINFILE occurrences and key target areas were prospected. A total of 59 rock chip samples were also collected during prospecting traverses.

In 2021, Wedgemount Resources Corp. completed a program of geochemical (rock and soil) sampling and spectral analysis on the area as the regionally extensive Cookie property. A grab sample (D704022) of diorite with localized malachite and trace disseminated pyrite, taken from the ridge directly north of the occurrence, assayed 0.974 per cent copper (Assessment Report 40029).