The Helen occurrence is located at 1690 metres elevation above sea level, between Robb and Twelve Mile creeks, in the Slocan Mining Division.

Regionally, the area lies on the western margin of the Kootenay Arc, in allochthonous rocks of the Quesnel Terrane. In the vicinity of the occurrence, the Quesnel Terrane is dominated by the Upper Triassic Slocan Group, a thick sequence of deformed and metamorphosed shale, argillite, siltstone, quartzite and minor limestone. Rocks of the Slocan Group are tightly and disharmonically folded. Early minor folds are tight to isoclinal with moderate east plunging, southeast inclined axial planes and younger folds are open, southwest plunging with subhorizontal axial planes. The sedimentary sequence has been regionally metamorphosed to lower greenschist facies.

South of the occurrence, the Slocan Group has been intruded by the Middle Jurassic Nelson intrusions which comprise at least six texturally and compositionally distinct phases ranging from diorite to lamprophyre. The most dominant phase is a medium to coarse grained potassium feldspar porphyritic granite. Several feldspar porphyritic granodiorite dikes, apparently related to the Nelson intrusions, also cut the sedimentary sequence near the occurrence (Paper 1989-5).

The occurrence consists of a brecciated vein within a northwest striking shear zone cutting a porphyritic granite stock-like apophysis of the Nelson intrusions. The shear dips 45 degrees southeast and is composed essentially of broken and crushed granite, 1 to 1.5 metres wide, sparsely mineralized with galena, cerussite, sphalerite and carbonate as filling between the granite blocks. A 45 centimetre wide chip sample taken from the mineralized portion of the shear assayed 1.3 grams per tonne gold, 1920 grams per tonne silver and 12 per cent zinc (Minister of Mines Annual Report 1919). The vein has been explored with a shaft and two adits driven 30 metres apart vertically.