The Rupert-L showing is located 35 kilometres southwest of Atlin on the west side of Taku Arm, Tagish Lake, just east of Fee Glacier.

The Rupert showing occurs near the contact of a gneissic assemblage of the Permian Boundary Ranges Metamorphic Suite (Stikinia terrane), on the west, with a Middle Devonian gneissic assemblage (Nisling terrane?), on the east. A few hundred metres east of the Devonian assemblage are granodiorites of the Early Jurassic Aishihik Suite. Tertiary rhyolite, andesite and basalt dikes of the Sloko-Hyder Plutonic Suite intrude the older units. The Llewellyn fault is 10 kilometres to the northeast.

A shear hosted quartz vein and associated alteration contains disseminated sulphides in a gangue of limonitic quartz and minor carbonate. Mineralization, in order of abundance, consists of pyrite, galena, pyrrhotite, chalcopyrite, and sphalerite. The vein is hosted in gneiss/schist and is spatially associated with at least one felsic dike. The vein is 20 to 50 centimetres in true width and has a known strike length of 15 metres.

The best values were from samples of mineralized quartz vein and altered material from trenches. Assays ranged from 0.045 to 0.220 grams per tonne gold, 4 to 29 grams per tonne silver, 0.0079 to 0.0096 per cent copper, 0.0400 to 0.2160 per cent lead, and 0.1170 to 0.31 per cent zinc (Assessment Report 21114).

The Rupert showings were probably discovered at around the turn of the century. Trenching, reported in 1913, located five mineralized quartz veins (Rupert-North, 104M 036). The Fee Group was staked to cover these showings in 1979 by United Keno Hill Mines Limited. They carried out extensive geological and geochemical surveys. In 1986, Rise Resources optioned the Ice 1 claim and the 10 Crown grants comprising the Rupert Group. Rise Resources confirmed the soil anomalies discovered by United Keno Hill Mines Ltd. Placer Dome optioned the property in 1989 and conducted mapping, geochemical sampling, and geophysical surveys. The Occurrence L showing was located in 1989 as a geochemical anomaly and in 1990, trenching was conducted on this anomaly.

In 2006, Eagle Plains Resources Ltd. collected one rock sample near the Rupert-L showing and results from this sample were considerably lower grade than previously reported values.

Refer to the Titan prospect (104M 089) for related details of the Titan property, of which the Rupert-L showing is part of.