The Blackjack Central trenches are found near the headwaters of the Manson River, 8 kilometres northeast of Mount Gillis. The access is by cat trail up Manson River which connects with a road to Takla Landing at Slate Creek (Assessment Report 1161).
Molybdenite is found in veinlets as disseminated in massive quartz veins within granodiorite, quartz monzonite and possibly, aplite of the Cretaceous Germansen batholith. This showing is located at the contact of an outlier of hornfelsed Upper Triassic Plughat Mountain Formation rocks (Takla Group). Lesser molybdenite-bearing quartz veins are found within these hornfelsed rocks. Associated with some of the molybdenite showings are pyrite, pyrrhotite and chalcopyrite.