The Seal Zinc-Silver silver deposit is located 20 kilometres to the west from the centre of the copper mineralization and within the same gross structural trend. The Seal deposit is stratabound hosted within an Ordovician carbonate and sandstone unit that is stratigraphically below the main copper mineralization at Storm.

Cominco discovered the Seal zone in 1995 when 14 holes drilled on the target are intersected high-grade zinc mineralization hosted by a poorly indurated sandstone unit. Drilling also identified intense hydrothermal alteration extending over a 600 metre long, 150 metre thick zone in the footwall carbonate units to the main massive sulphide zone.

The zinc mineralization at Seal consists of massive to disseminated and vein-fill sphalerite, marcasite and minor pyrite hosted by a clean, white sandstone unit at the base of the Ordovician Ship Point Formation. The Seal zone falls into the Irish-Type or Mississippi-Valley Type of zinc deposit with coarse reddish-brown sphalerite as the dominant ore mineral.

Noranda, under an option agreement with Cominco, drilled a series of holes in 2001 to test the large footwall alteration zone for additional mineralization. No further additions to the resource potential were made from this drilling, but Noranda recommended further testing of the Seal target area.