The Yehiniko East occurrence is located near the head of Yehiniko Lake approximately 28 kilometres east of the Stikine River.

The showing is located within Upper Triassic rocks of the Stuhini Group near the western margin of tonalite pluton of the Middle Jurassic Three Sisters Plutonic Suite. The volcanic sequence consists mainly of massive to faintly feldspar and/or pyroxene porphyritic andesitic flows with lesser intercalated beds of siltstone, lapilli tuff and volcanic conglomerate. The beds generally strike northwest and dip moderately to the southeast. The package is not highly deformed although it is possible that north trending, vertical faults crosscut the area.

Souther (Geological Survey of Canada Paper 71-44) simply states that a large alteration zone occurs around the contact between the pluton and volcanic rocks and contains some copper mineralization.

It is reported that regional stream geochemistry (RGS) data shows elevated copper values in stream sediments draining the Yehiniko east area.