The Rosa showing is located near the confluence of Skilet and Erie creeks, about 14 kilometres southwest of Ymir. The area was first explored in the 1890's. The workings, comprising 2 adits, are now included in the Erie Creek property. The Copper King (082FSW213), the Arnold (082FSW301), Ben Hassen (082FSW300) and Hattie (082FSW226) occurrences are also part of this property.

The area is underlain by the Lower Jurassic Rossland Group, Elise Formation volcanics and Archibald Formation sediments. The Rossland Group rocks are intruded by the Middle to Late Jurassic Nelson Intrusions, locally known as the Erie stock. The Erie stock is comprised of a light grey quartz monzonite with associated aplitic and feldspar porphyry dykes. Biotite hornfels is apparently a contact metamorphic effect related to both the Nelson batholith and the Erie Creek dyke swarm. It is mainly developed in argillite and siltstone. Chlorite occurs mainly on fractures and in shear veins in augite andesite and hornfels.

Mineralization on the property occurs roughly in four concentric zones. An inner quartz-molybdenum plus scheelite zone followed by a chalcopyrite zone, a pyrite-pyrrhotite zone and an outer sphalerite- galena zone. The inner zone is approximately 600 metres in diameter and is centered on the east side of Erie Creek (Hattie). The host rocks are quartz monzonite dykes, stocks and white rhyolite. The chalcopyrite zone occurs over an area of 1.5 to 2 kilometres and occurs in quartz and sulphide veinlets as fracture coatings and in shear veins with pyrite, pyrrhotite and minor amounts of scheelite. The best copper values obtained, up to 1.3 per cent, were from vein and dump samples mainly from old workings on the west side of Erie Creek (Drum Lummon, Copper King, Dora, Homestake). Pyrite and pyrrhotite, in an area about 1.5 by 2.5 kilometres, occurs finely disseminated and as fracture coatings. Sphalerite and galena with some gold occurs in shear veins beyond the inner zone, such as the Arnold and Ben Hassen showings.

Sphalerite and galena in quartz gangue occur in shear veins on the Rosa Reverted Crown Grant. In 1987, a sample taken from an old adit along Skilet Creek assayed 213.2 grams per tonne silver and 0.015 gram per tonne gold (Assessment Report 15510).

The mineralization is believed to be part of a zoned porphyry type deposit which has a central quartz vein stockwork zone contain- ing molybdenum-copper-tungsten mineralization and a peripheral zone with veins containing copper, lead, zinc and silver mineralization. This showing is interpreted as occurring in the peripheral zone.