The U.S. occurrence is located at 2125 metres elevation above sea level on Crown grant Lot 1055, 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).
On the U.S. Crown grant, the Slocan Group rocks consist of interbedded pyritic slate and argillite. The strata strike north, dip 55 degrees east and are intruded by mafic and felsic dikes. The occurrence consists of three separate brecciated fissure veins that have been exposed in four adits. The main vein is conformable to bedding, 1 to 5 centimetres wide, and consists of bands of pyrite associated with sparsely disseminated sphalerite. The fissure is marked by several centimetres of gouge and crushed siliceous argillite. A second fissure vein, 200 metres northeast of the main vein, strikes northeast and dips 50 degrees southeast. This vein consists mainly of 10 to 20 centimetres of gouge and crushed argillite carrying disseminated pyrite and veinlets of galena and sphalerite along joints and fractures within the argillite. A third vein, 100 metres south of the main vein, strikes 050 degrees and dips southeast. This vein is at the contact between argillite and a mafic dike. It consists of broken quartz mineralized with disseminated pyrite.
Records indicate that 163 tonnes of ore were mined from the property between 1913 and 1914 to produce 8528 kilograms of zinc (Geological Survey of Canada Memoir 173, page 81).
