The Westrim 4 occurrence is located in a steep gully on the western side of Goldrim Creek at an elevation of approximately 550 metres.

The area is underlain by Karmutsen Formation basalts, Quatsino Formation limestone and Parson Bay Formation calcareous siltstone, all of the Upper Triassic Vancouver Group. These in turn are overlain by Lower Jurassic Bonanza Group flows, tuffs and breccias ranging from basalt to rhyodacite in composition. Quartz diorite to quartz monzonite of the Early to Middle Eocene Tofino Intrusive Suite (previously Catface Intrusions) and quartz diorite and granodiorite of the Early to Middle Jurassic Island Intrusions also disrupt area strata..

Locally, the fault contact between Karmutsen volcanics and Quatsino limestone is the setting of magnetite skarn. The contact strikes 224 degrees and dips 60 degrees to the south east. A 0.3 metre thick calcite-chlorite-quartz cemented breccia marks the contact zone. The zone thickens to a 1.2 metre wide quartz-calcite lens mineralized with pyrite. The magnetite skarn is developed in the limestone as a 2 to 4 metre wide zone continuing along the contact in both strike directions. The skarn is composed mainly of magnetite, garnet with minor quartz, clinopyroxene, pyrrhotite and pyrite. A 15 metre drift was driven along this zone in early 1900’s.

During 1992 through 1995, W. Guppy completed programs of prospecting, geochemical sampling and a ground electromagnetic survey on the area as the Goldrim claims and Westrim claims. Sampling of the skarn assayed up to 1.26 per cent zinc and 32.13 per cent iron; while a sample (200) of the quartz-calcite vein following the fault contact assayed 0.92 grams per tonne gold and 3.5 grams per tonne silver across 0.3 metre (Assessment Report 23901).