The Unuk River area is underlain by a thick Upper Triassic- Middle Jurassic volcano-sedimentary succession which is overlain by marine basin sediments of Middle to Upper Jurassic age. The sedimentary and volcanic rocks have been cut by a variety of plutons representing at least four intrusive episodes spanning late Triassic to Tertiary time. Major structural features apparent in the area are north trending folds and a major normal fault known as the Harrymel Creek fault. A number of lesser normal faults which repeat stratigraphy are recognized at the toe of Bruce Glacier. Metamorphism in the area has been determined to be lower greenschist facies.

The Unuk River (AP) occurrence area is underlain by a package of Lower Jurassic Betty Creek Formation (Hazelton Group) intermediate and felsic volcanic rocks and related sedimentary rocks, and possibly felsic volcanic rocks and sedimentary rocks of the Lower Jurassic Mount Dilworth Formation (Hazelton Group). The AP zone is a moderately strong, continuous crosscutting zone of brecciation, silicification, carbonatization and related galena-sphalerite-pyrite- arsenopyrite-(chalcopyrite) mineralization. It is hosted by welded tuffs, tuffaceous mudstones and argillaceous sediments within felsic volcanic rocks of the Betty Creek and possibly Mount Dilworth formations. A multitude of crosscutting, anastomosing diabase dykes occur throughout the zone. The zone extends over 300 metres along strike and may join with other mineralized structures in the area (see Unuk (Zone 1), 104B 083 and Unuk (Zone 2), 104B 344).

A drill core intersection across a true width of 1.36 metres assayed 1.25 grams per tonne gold, 20.7 grams per tonne silver, 0.035 per cent copper, 1.087 per cent zinc and 0.9 per cent lead (Assessment Report 20993).