The Motherlode occurrence is located on a small south-flowing tributary, approximately 1.5 kilometres north of its junction with Monk Creek on the southwest slopes of Mount Irene at 1750 to 1850 metres elevation. The Copper Queen (MINFILE 082FSE053) of similar mineralization may adjoin to the south, at a slightly lower elevation.

Regionally, the area is underlain by quartzite and quartz arenite sedimentary rocks of the Three Sisters Formation; argillite, greywacke, wacke and conglomerate turbidites of the Monk Formation; greenstone and greenschist metamorphic rocks of the Irene Formation and conglomerate and coarse clastic sedimentary rocks of the Toby Formation, all of the Neoproterozoic Windermere Supergroup. To the west, these units have been intruded by granodioritic rocks of the Cretaceous Anstey pluton, whereas to the north and south large bodies of Middle Jurassic granitic intrusives are exposed.

Locally, mineralization occurs in sheared greenstone of the Irene Formation, underlain to the east by pebble conglomerate of the Toby Formation. Both these units are metamorphosed to chlorite facies of regional greenschist metamorphism. Mineralization is associated with a zone of fracturing and veining that trends north and dips steeply west, across a maximum width of 6 metres and strike length of 75 metres as exposed in numerous surface trenches and opencuts. In addition to rusty gossan, pyrite, chalcopyrite, pyrrhotite and a little galena are exposed in a gangue of quartz, ankeritic carbonate and sericitic material.

Samples of dump material assay up to 2.4 per cent copper, 154 grams per tonne silver and trace gold; rusty gossan samples (in which gold is probably enriched) assay up to 7 grams per tonne gold (Minister of Mines Annual Report 1937).

The Motherlode claim was staked prior to 1937 with development work of at least seven trenches and/or opencuts being reported.

In 1991, Cominco Ltd. prospected and sampled the area immediately north as the Irene 1-3 claims. This work identified several chalcopyrite-bearing quartz veins in outcrop and subcrop in the southern head waters of Char Creek. See the Irene (MINFILE 082FSE134) occurrence for more information.

In 2017, Crucible Resources Ltd. completed a program of rock, silt and soil sampling on the area as the Irene Trend property.