Copper mineralization occurs in the quartz dioritic Middle to Late Triassic Nightout Pluton batholith near its northern contact with Devonian to Permian sediments of the Stikine Assemblage. In 1973 mapping by Bart Mines intrusive rocks were described as granodiorite. A pyritic felsite dike up to 30 metres wide cuts all other rocks and one outcrop of greywacke was noted.

On Bart Mines claim BM 38 (Outcrop #39 showing), chalcopyrite is disseminated in fractured granodiorite across a 15-centimetre width. The fractures have a strike of 10 degrees with a vertical dip. Another copper showing (Outcrop #41 showing), within a few hundred metres south-southeast occurs in a 60-centimetre wide shear in granodiorite. The shear has a 215 degree strike and a vertical dip. The shear is bounded by irregular quartz-calcite veinlets mineralized with chalcopyrite.

In 1973, Bart Mines Ltd conducted geological mapping on their B and EM claims over Nightout Mountain.