The F3 (SB) occurrence is located in the headwaters of Chipman Creek.

The area is underlain by metasedimentary rocks of the Mississippian to Pennsylvanian Fourth Lake Formation (Buttle Group) and volcanic rocks of the Upper Devonian McLaughlin Ridge Formation (Sicker Group). These two formations were historically referred to as the Myra Formation and contained the ‘Sediment-Sill unit’ of the Sicker Group. The Sediment-Sill unit has been tentatively correlated with the Fourth Lake Formation and the ‘sills’ have been mapped separately. The sills are believed to be coeval with the Karmutsen Formation basalts and are informally named Mount Hall gabbro. These rocks have been intruded by granitic rocks of the Early to Middle Jurassic Island Plutonic Suite.

Locally, sedimentary rocks are in or near contact with granodiorite and host ferrous breccia with a high magnetite content and anomalous gold and copper.

In 1989, a sample of sub-crop exposed on a logging road assayed 20 per cent iron, 230 parts per billion gold and 449 parts per million copper (Assessment Report 18755).