Cardiac Creek Zinc-Lead-Silver Deposit: Update and Insights on a Growing Resource, Akie Property, British Columbia
Nicholas Johnson, Exploration Manager, Canada Zinc Metals Corp.
The Cardiac Creek deposit, Akie property, is located in the Akie River Valley of northeastern British Columbia, approximately 260 kilometres NNW from the town of Mackenzie. The property is situated within the Kechika Trough, the southeast extension of the prolific Selwyn Basin. The sequence of fine‐grained clastics from the late Devonian Earn Group are considered the prospective rocks in the Kechika Trough. Specifically, all of the deposits (Cardiac Creek, Cirque) and occurrences (Mt. Alcock, Elf) are hosted by the carbonaceous, siliceous shales of the Gunsteel formation, the basal unit of the Earn Group.
The Cardiac Creek deposit has been the focus of Canada Zinc Metals exploration efforts since September2005. The deposit is a NW‐SE trending, SW dipping planar body of mineralisation with current approximate dimensions of 1300 metres in strike length and a dip extent of 800 metres. To date, the deposit has been tested by 79 drill holes totaling just over 42,600 metres, including 8 drill holes in 2015. Drilling from 2011 and earlier defined a NI43‐101 compliant indicated resource of 12.7Mt grading 8.4% Zn, 1.7% Pb and 13.7g/t Ag and an inferred resource of 16.3Mt grading 7.4% Zn, 1.3% Pb and 11.6g/t Ag (at a 5% Zn cut‐off grade).
Stratigraphically, the mineralisation is positioned just above the base of the Gunsteel formation and is underlain by debris flows of the Paul River formation and siltstones of the Road River Group. The mineralisation is located at a transition point between the Kwadacha Reef to the east and deep‐water clastics to the west. The deposit, marked along its upper contact by a distinctive quartz‐carbonate vein zone, appears to be bifurcated into two distinct horizons, the Cardiac Creek Zone and the Footwall Zone. The mineralisation is characterised by two distinct facies: Proximal facies, defined by thickly bedded fine‐grained dull brown pyrite with minor sphalerite banding, and the Cardiac Creek Zone, defined by thick bands of steel grey sphalerite and galena interbanded with pyrite, barite and shale. High‐grade Zn and Pb is associated with a quartz‐barite mottled texture within the sphalerite bands.
Since 2011, the company has focused on expanding the known limits of mineralisation as well as defining the high‐grade core of the deposit which remains open primarily down‐dip and along strike to the northwest. Aspects such as: element ratios, localized alteration, sulphide breccias, the presence of massive sulphide lenses and, surprisingly, concretions all correlate with the high‐grade core. Recently, airborne geophysics (VTEM and Gravity) have been used to define lithological units, structure and provide a deposit signature to assist exploration on the property and regionally.
Drilling since 2010 has also intersected several thin intervals of mineralisation associated with Paul River formation rocks that are enriched in a suite of elements including Ni, Zn, Pb, Mo, U, V. This represents a new style of mineralisation in the Kechika Trough and is similar in character to the Nick deposit, Yukon.