The Little Robert area is underlain by limestone of the Lower Cambrian Badshot Formation and metasediments of the Cambrian to Devonian Index Formation (Lardeau Group) consisting of schist, phyllite, quartzite, slate and limestone.

A 45-metre band of marble forms the divide between McDonald and Ferguson creeks. The marble lies between dark grey to black, carbonaceous, calcareous schists and slates. The sediments strike 130 degrees and dip steeply west. Numerous quartz veins carrying pyrite occur in both slates and limestone.

In the late 1890s, development work was started on a 0.6 to 1.5-metre wide quartz vein in marble. Opencuts were excavated at 2194 metres elevation and a crosscut adit, begun at 2133 metres with the intention of cutting the veins at depth, was driven 29 metres. Mineralization consists of galena and tetrahedrite in quartz gangue.

In 1914, it was reported that two small shipments of sorted ore had been made (Minister of Mines Annual Report 1914, page 313). A 90 kilogram sample gave an assay of 3799 grams per tonne silver and 21.5 per cent lead. A 2250 kilogram sample assayed 3909 grams per tonne silver and 24 per cent lead.

During 2006 through 2009, Mineral Mountain Resources Ltd. completed programs of prospecting, geochemical (soil, silt, talus fines and rock) sampling and an airborne geophysical survey on the area as the Kootenay Arc property.