The Dark Star deposit is considered to be Carlin-type, sedimentary-rock-hosted deposits. Precious metal mineralization is generally submicroscopic, disseminated, and hosted principally in sedimentary rocks, with some mineralization in felsic dikes and sills as well.
The Dark Star Main (“Dark Star Main”) and Dark Star North (“Dark Star North”) zones, which comprise the Dark Star deposit, are hosted primarily within Pennsylvanian-Permian rocks, with minor amounts of gold mineralization found in the Chainman Formation and Tertiary conglomerates. The deposits are centered along the roughly north-south Dark Star fault corridor, within which is a horst block and associated silicified zone bounded by the West fault and Dark Star fault. Gold mineralization in the horst block is hosted in the middle, coarse-grained conglomeratic and bioclastic limestone-bearing unit of a Pennsylvanian-Permian undifferentiated sequence interpreted to be equivalent to the Tomera Formation. Mineralization dips steeply to the west near the surface at Dark Star Main and Dark Star North, but dips less steeply at depth at Dark Star Main.