The Ben 28 occurrence consists of copper-molybdenum mineralization in mountainous terrain 15 kilometres south of the southern end of Tatlayoko Lake. It is related to similar mineralization covered by the Ben 37 occurrence (092N 004), 1.7 kilometres to the southwest.

The area is underlain mostly by a granodioritic intrusion of the Late Cretaceous to Paleocene Bendor suite (no longer correlated with the Paleocene Tiedemann pluton) on the northeastern margin of the Jurassic to Tertiary Coast Plutonic Complex. The pluton contains northeast-striking shear zones, some of which contain lamprophyre or granite dikes. Intruded country rocks are volcanic and sedimentary rocks of the Late Triassic to Cretaceous Eastern Waddington thrust belt imbricate zone and Cretaceous Taylor Creek Group. At the contact with the younger batholith rocks, the country rocks are metamorphosed, fractured and impregnated with iron sulphides and veins of quartz, calcite, aplite and pegmatite. Weathering of iron sulphides in the contact zone has formed gossans in places.

The granodiorite contains fracture-controlled pegmatitic quartz veins containing coarse chalcopyrite and molybdenite (Assessment Report 2670). The density of fractures and veining varies, and at least 3 common orientations are present. Individual quartz veins range from 2 to 25 millimetres in thickness.

In 1970, geological mapping on the Ben 1 to 143 mineral claims by Pacific Petroleum Ltd outlined a deposit extending over an area of 900 by 120 metres estimated (not substantiated) to grade 0.1 per cent copper and 0.002 per cent molybdenum (Assessment Report 2670). Geological mapping was done on scales of 1 inch: 1,000 feet and 1 inch to 200 feet. A picketed grid controlled the 1 inch to 200-foot mapping.