The Tan occurrence is located about 26 kilometres southwest from the community of Dease Lake.

The showing area is underlain by Upper Triassic Stuhini Group andesitic tuffs, volcaniclastic rocks and fine sedimentary breccias with siltstone bands. The volcano-sedimentary sequence is intruded by minor peridotite and diorite bodies.

Low to moderate amounts of magnetite and pyrite occur throughout the property. Minor chalcopyrite occurs in carbonate shears in tuffs.