The Mamquam 2-3 occurrence is located in the southwestern head waters of Mamquam River, at an elevation of approximately 1100 metres, 2.2 kilometres northeast of Clarion Lake.

The area is underlain by a roof pendant of rhyolitic and andesitic tuff and agglomerate of the Lower Cretaceous Gambier Group. The volcanic rocks overlie Late Jurassic leucocratic granodiorite of the Jurassic to Tertiary Coast Plutonic Complex. The elongate, keel shaped, roof pendant trends west-northwest for 2 kilometres and is up to 1 kilometre wide.

Locally, pyritic and altered rhyolites host sulphide veins and disseminations consisting of pyrite, chalcopyrite, sphalerite and possible minor galena.

In 2005, a rock sample (M-23) from a massive sulphide vein assayed 0.98 gram per tonne gold, 5.1 grams per tonne silver, 0.81 per cent copper, 0.17 per cent lead and 4.39 per cent zinc (Assessment Report 28441). The following year, a sample (M42) from an alteration zone hosting pyrite assayed 1.7 per cent copper and 40.9 grams per tonne silver (Assessment Report 29120).

Another area of mineralization, located at approximately 1020 metres elevation in the main creek bed to the east, is reported to consist of chalcopyrite in an area of heavy pyrite with shearing and fracturing.

During 1980 through 1982, Alpen Exploration completed programs of rock, soil and silt sampling, prospecting and a ground magnetometer survey on the area as the Ursula, Diddi and Sarah claims. During 2005 through 2015, the area was prospected and sampled as the Mamquam 1-5 claims.