History
The Eskay Creek Project area has a long exploration history, dating back to initial prospecting activities in 1932. Companies with Eskay Creek Project interests prior to Skeena’s involvement include Premier Gold Mining Co. Ltd., MacKay Gold Mines Ltd., Canadian Exploration Ltd., American Standard Mines Ltd., Pioneer Gold Mines of B.C. Ltd., New York-Alaska Gold Dredging Corp., Western Resources Ltd., Stikine Silver Ltd., Canex Aerial Exploration Ltd., Mount Washington Copper Co., Newmont Mining Corp., Kalco Valley Mines Ltd., Texas Gulf Canada Ltd., May-Ralph Resources Ltd., Ryan Exploration Ltd. (“U.S. Borax”), Kerrisdale Resources Ltd., Consolidated Stikine Silver Ltd., International Corona Corp., Homestake Canada Inc., and Barrick. Work conducted during this period included prospecting, geological mapping and reconnaissance, rock, stream, sediment, and soil geochemical sampling, trenching, surface geophysical surveys (electromagnetic (“EM”), very low frequency (“VLF”), ground magnetic/VLF-EM, induced polarization, seismic refraction, University of Toronto electro-magnetic system), borehole geophysics (frequency domain EM) core drilling, exploration adit and underground development, petrography, and mining studies.
Underground mining operations were conducted from 1994 to 2008. From 1995–2006, ore was direct-shipped after blending and primary crushing. From 1998 to closure in 2008, ore was also milled on site to produce a shipping concentrate.
Skeena has completed geological mapping, soil and grab sampling, rotary air blast and core drilling, an airborne light detection and ranging (“LiDAR”) and photo acquisition survey, Mineral Resource and Mineral Reserve estimation, metallurgical testwork, environmental testwork and supporting studies, and mining studies. A preliminary economic assessment was completed in 2019, a pre-feasibility study in 2021, and a feasibility study in 2022.
Geological Setting and Mineralization
The Eskay Creek deposit is generally classified as an example of a high-grade, precious metals-rich epithermal volcanogenic massive sulphide (“VMS”) deposit; however, it has also been suggested to be an example of a subaqueous hot spring gold– silver deposit.
The Eskay Creek Project is located along the western margin of the Stikine Terrane, within the Intermontane Tectonic Belt of the Northern Cordillera. It is hosted within the Jurassic rocks of the Stikinia Assemblage at the stratigraphic transition from volcanic rocks of the uppermost Hazelton Group to the marine sediments of the Bowser Lake Group.
In the Eskay Creek Project area stratigraphy comprises an upright succession of the Lower to Middle Jurassic Hazelton Group, including andesite, marine sediments, intermediate to felsic volcaniclastic rocks, rhyolite, contact mudstone (host to the main Eskay Creek deposits) (“Contact Mudstone”), and basaltic/andesitic sills and flows. This sequence is overlain by mudstones and conglomerates of the Bowser Lake Group.
Several styles of stratiform and discordant mineralization are present at the Eskay Creek Project, defined over an area approximately 1,400 m long and as much as 300 m wide. Distinct zones have been defined by variations in location, mineralogy, texture, and precious metal grades.
Stratiform-style mineralization is hosted in black carbonaceous mudstone and sericitic tuffaceous mudstone of the Contact Mudstone, located between the footwall Eskay Rhyolite member and the hanging wall Willow Ridge andesite unit. The stratiform-hosted zones include the 21A, 21B, 21Be, 21C, 21E, and North Extension (“NEX”). Stratigraphically above the Contact Mudstone, and usually above the first basaltic sill, the mudstones also host a localized body of base metal-rich, relatively precious metal-poor, massive sulphides referred to as the Hanging Wall (“HW”) Zone. Stratabound-style mineralization is also hosted stratigraphically below the Rhyolite and is hosted within the Lower Mudstone, Dacite, Even Lower Mudstone and Footwall Andesite, in the 23 Zone (formerly Lower Package (“LP”) Zone).