The Gwillim property is located in the Barlow township, close to Chibougamau, consisting of 38 mining claims, covering 1715 Ha.
The Gwillim property is underlain by massive and pillowed mafic to intermediate volcanics of the upper Gilman Formation. Andesite predominates in the north, whereas basalt is dominant in the southern half of the property. Pillows indicate tops to the south. The volcanics are locally intercalated with volcanoclastic sediments, which occur on the north flank of the east trending Chibougamau syncline. The Blondeau Formation, a series of felsic volcanic and volcaniclastic rocks and graphitic shales, underlies the southwest part of the property. Dioritic and gabbroic sills, up to 250m wide, intrude the volcanic units parallel to the lake. These are considered co-magmatic with the host volcanic rocks. The volcanics and intrusives rocks host disseminated and fracture filling pyrite and occasionally pyrrhotite and chalcopyrite. The sills are magnetic with disseminated magnetite and in the diorite the magnetite is not evenly distributed. All of the volcanic units are carbonatized with calcite forming along foliation planes and microfractures, and pervasive chlorite alteration.
Gold mineralization on the Gwillim property appears to be related to an early episode of east-west shearing, in turn possibly related to the Gwillim Lake. The Cadillac vein, as an example of this, consists of milky to smoky quartz with ankerite, chlorite, sericite, tourmaline and varying amounts of pyrite and traces of chalcopyrite. Gold mineralization is erratic and discontinuous with local very high grades.