The Mentor occurrence is located near the south eastern shore of Nechako Reservoir, approximately 3 kilometres northwest of Zinc Bay. All workings on these claims were flooded when the level of Whitesail Lake was raised.

The area is underlain by calc-alkaline volcanic rocks of the Lower Jurassic Telkwa Formation (Hazelton Group) and undivided sedimentary rocks of the Middle Jurassic Smithers Formation (Hazelton Group). These have been intruded by intrusive rocks of the Eocene Coast Plutonic Complex(?) to the south east.

Locally, a 3 to 4.5 metre wide shear zone, striking 335 degrees and dipping 60 to 75 degrees east hosts veinlets of quartz and calcite that occupy fractures are mineralized with sphalerite, galena, pyrite, chalcopyrite and arsenopyrite. The veinlets are up to 38 centimetres wide and the mineralization occurs in lenses up to 1.8 metres in length.

In 1917, a 0.35 metre wide stringer within the sheared rock yielded ‘trace’ amounts of gold, 41 grams per tonne silver and 30.5 per cent zinc. In 1927, samples of individual seams of mineralization assayed up to 82 grams per tonne gold and 54 per cent zinc over 0.10 metre. In 1949, a sample collected from a vein near the portal by S. Duffel assayed 0.7 gram per tonne gold, 112 grams per tonne silver, 10.2 per cent lead and 13.7 per cent zinc (Assessment Report 33439).

Approximately 240 metres west of the portal, an open cut exposed two parallel veins, each about 0.30 metre wide, striking 345 degrees with vertical dips. A sample from these veins yielded 0.4 gram per tonne gold, 28 grams per tonne silver and 28.5 per cent zinc (Assessment Report 33439).

In 1916, the Mentor, Sunset and Cariboo group of claims were staked along the south shore of Whitesail Lake, near Zinc Bay. The ground was optioned to a Prince Rupert-based syndicate who developed underground workings, consisting of a 15 metre adit and 30 metre cross-cut, at lake level (now submerged). In 1989 and 1990, Equity Silver Mines completed programs of geological mapping and rock, silt and soil sampling on the area to the south and east as the Midnight claims. In 2006, Christopher James Gold, on the behalf of Guardsmen Resources, prospected the area as the Zinc Bay property. In 2011, Jet Gold, on behalf of Guardsmen Resources, completed a program of rock sampling and airborne magnetic and electromagnetic surveys, totalling 476 kilometres on the area. The airborne survey encompassed the area of the Mentor.