The Tarn area is underlain by Devonian sedimentary and volcanic rocks of the Stikine Assemblage. The Devonian Forrest Kerr Pluton is in contact to the immediate west of the Stikine package. Plutonic rocks consist primarily of Late Devonian granite and diorite.

Chalcopyrite and gold occurs within an iron carbonate healed breccia and shear zone in an area of tuff and phyllite. Previous hand trenching traced the structure for 18 metres and selected results include a maximum value of 12.10 grams per tonne gold, 118.3 grams per tonne silver and 22.4 per cent copper from a grab sample (Assessment Report 20562). Two holes, AVD 90-19 and AVD 90-20 were drilled at in order to intersect the easterly dipping mineralized structure. Both holes hit the targeted structure as characterized by brecciation, increased quartz-carbonate veining and low core recoveries. Gold-copper values in hole 19 were all low while a one metre interval from 33 to 34 metres in hole 20 assayed 0.65 gram per tonne gold (Assessment Report 20562).

Visible gold in narrow quartz veins were noted at the VG showing about 200 metres to the south-southwest.

A float and bedrock occurrences of tetrahedrite, chalcopyrite, malachite and occasional asbestos are hosted by quartz and/or calcite veinlets at the Tetra showing, located about 400 metres west of the Tetra area. The showings in the area are small and contain no appreciable gold values.

The Tarn showing was discovered in 1989 and was hand trenched that year. In 1990 Avondale Resources conducted a program on the Tarn that included mechanized trenching, diamond drilling, prospecting and VLF-EM/magnetometer surveys.

Refer to the Forrest occurrence (104B 380) for a common work history of the Forrest Property.