Molybdenum Deposit Discovered on Hudson Bay Mountain

The Glacier Gulch, or Hudson Bay Mountain, deposit of molybdenum and tungsten, here on the east flank of Hudson Bay Mountain, was first reported by the Geological Survey of Canada in 1944. It’s also called Yorke-Hardy, named after the person who originally staked it. This whole area is about 9 kilometers northwest of Smithers in west-central British Columbia.

The molybdenum-tungsten mineralization here crops out over five square kilometers and goes down to depths of two kilometers. Features like a hornblende-biotite aureole and mineralogical zoning, along with the dike, vein, and fracture geometries you see within the Middle to Lower Jurassic Hazelton Group and Cretaceous Skeena Group lithologies, all point to an intrusive complex. That’s the Upper Cretaceous to Early Tertiary Hudson Bay Mountain stock, which drill holes have intersected, and it’s believed to be what caused all this mineralization.

There's also a granodiorite sill, which dips southeast, that drilling has outlined within the Hazelton Group. Molybdenite and scheelite veins cut through all the different rock types, but the granodiorite sill actually hosts a higher density of fine-grained, banded, quartz-molybdenite and pegmatitic quartz-molybdenite veins. This is because of a competency contrast between the intrusive sill and the other country rock. Because there are so many of these veins, the grade of the deposit is higher within the areas of the sill.

Above the 15,000-foot cross-cut, 20.6 million tonnes have been defined, grading at 0.401% MoS2 and 0.041% W03. During the exploration of this deposit, they even had to adjust their sampling procedures. That was due to something called the nugget effect, which they attributed to the drill intersections of those banded and pegmatitic veins.

Hudson Bay Mountain itself is a pretty dominant feature, reaching 2590 meters in elevation, and it’s on the southern edge of the Bulkley Valley. Part of this mineralization is actually covered by the Kathlyn Glacier, which you can see from Highway 16. There are 3100 meters of underground development here, and you can get to it from a portal at 1066 meters elevation on the east slope of the mountain.