The Mount Alcock occurrence area is located about 1 kilometre northeast of the summit of Mount Alcock and 7.7 kilometres northeast of the confluence of the Warneford and Kwadacha rivers, approximately 202 kilometres southwest of Fort Nelson or about 211 kilometres north of Germansen Landing.
The Mount Alcock area is underlain by a fault-bounded wedge of Devonian to Mississippian Earn Group shales surrounded by Ordovician to Devonian Road River Group siltstones.
In a saddle, on the north side of Mount Alcock, a 230 metre long, 20 metre wide curvilinear body of barite, containing bands of pyrite, galena and sphalerite, forms a prominent white-kill zone. The barite is hosted within Upper Devonian Gunsteel Formation shales (lower Earn Group).
Drilling indicates that the body is terminated at a depth of 130 metres by a northeast trending fault. A representative drill core assay graded 3.7 per cent zinc, 3.19 per cent lead, and 23.3 grams per tonne silver over 11 metres (Assessment Report 19829).
In the late 1960s, regional exploration for sediment-hosted lead-zinc in northeastern British Columbia was generated due to the recognition of clastic-hosted stratiform baritic sulphide deposits of the West German-type in the Yukon (MacMillan Pass). In 1970, the first major program in the Kechika Trough was conducted by Geophoto Consultants and focused on the potential of the property to host sedimentary exhalative (SEDEX) lead-zinc-silver mineralization. Exploration was further intensified by the 1971 discovery of the carbonate-hosted lead-zinc Robb Lake deposit (094B 005). In 1974, Placer Development Ltd. discovered several Devonian-aged barite sulphide occurrences including Driftpile Creek (094K 066) located 54 kilometres north of Mt. Alcock. The first major discovery, the Cirque (Stronsay) deposit (094F 008), was made by Cyprus Anvil and Hudson’s Bay Oil & Gas in 1977. The Mt. Alcock barite-hosted sulphide occurrence was discovered in 1977 by Cyprus Anvil Mining Company. Grab samples from a 2-3 metres thick mineralized zone within the barite kill zone yielded up to 14.8 per cent combined lead-zinc and 18.6 grams per tonne silver.
In 1989, the Mount Alcock area (part of the Kwadacha Recreation Area) was opened for mineral exploration with Triumph Resources Ltd., funded by Teck Exploration, becoming the successful bidder. During 1989, Triumph carried out a program consisting of mapping, prospecting, stream sampling; establishing and soil sampling a grid overlying the barite-sulphide showing; conducting 7 kilometres of induced polarization (IP) survey over the same grid and testing the downdip extension of the mineralized zone with nine diamond-drill holes totalling1111 metres. Drilling indicated the main showing area to be structurally complex with one of the best intersections containing 8.8 metres of 9.3 per cent combined zinc-lead (hole 89-3). Mapping and sampling within Devonian black shales northeast of the main showing revealed nodular barite zones as well as anomalous (zinc-lead) drainages and soils. In 1990, Triumph carried out a diamond drilling program totalling 1211.6 metres in six holes. The holes tested IP and geochemical targets (proximal to the main showing) and the downdip extension of the main showing. No significant massive sulphide intercepts were obtained.
In 1992, Teck Corporation conducted 1:5000-scale mapping with concurrent rock sampling. In addition, two grids were established and soil sampled, with a gravity survey carried out over selected portions of one grid. The purpose of the program was to test for an economic barite-hosted zinc-lead massive sulphide deposit hosted within Devonian black shales. Mapping and soil, rock and stream sampling was concentrated within the black shales. A total of 741 soil samples on 21.5 kilometres of grid line were collected on two grids; the Nod Grid and Seep Grid. In addition, 57 rock chip, 29 moss mat, 5 silt and 6 iron seep samples were collected. A ground gravity survey (4.1 line-kilometres) was carried out over selected portions of the Nod Grid.
In 2008, Canada Zinc Metals Corp. obtained 100 per cent ownership of the Mount Alcock property (National Instrument (NI) 43-101 Report on the Mount Alcock Property, BC, Canada Zinc Metals Corp., May 31, 2012). In 2008, Mantle Resources Inc. and Canada Zinc Metals Corp. conducted prospecting, rock and soil sampling at the NOD grid, reviewed historical core, initiated digitization of historical exploration data and completed rock sampling and prospecting at the Main showing (NI 43-101 Report on the Mount Alcock Property, BC, Canada Zinc Metals Corp., May 31, 2012).
In 2011, work on the Mount Alcock property included a property-scale silt sampling program designed to provide geochemical information from key drainages, infill and extension soil sampling, with a total of 259 samples taken and an evaluation of the historical drillcore for due diligence purposes. The Mount Alcock property has yielded a historical drill intercept of 8.8 metres grading 9.3 per cent zinc plus lead, and 40 grams per tonne silver (Press Release - January 11, 2012).
In 2012, Canada Zinc Metals Corp. completed a versatile time domain electromagnetic (VTEM) geophysical survey on the Kechika regional project. Preliminary interpretative results generated from the VTEM data indicate an excellent correlation between the known geological and structural data and the electromagnetic conductivity response generated from the survey. The results also defined the western panel of Gunsteel Formation shale and associated rocks on the Mount Alcock property and suggest an increased level of structural complexity compared to the existing mapping (Press Release - February 26, 2013).
In 2013, Canada Zinc Metals Corp. collected a total of 615 soil samples on the northwest and southeast extensions to the main soil grid to test electromagnetic (EM) trends identified by the 2012 VTEM survey. The EM trends appear to represent strike extensions of known occurrences of Gunsteel Formation shale. The 2013 sampling expanded the strike extents of the northwest-trending lead-zinc soil anomaly that corresponds to the main barite showing originally outlined by historical soil sampling. The anomaly now extends over a distance of 3.25 kilometres with an approximate width of 600 metres. The anomaly is coincident with mapped Gunsteel Formation shale and its central core overlies the massive barite occurrence that has been the focus of limited historical diamond drilling.
In September 2015, preliminary results of a heliborne gravity gradiometry survey flown between November 2014 and March 2015 over the Akie, Yuen North, and Mt. Alcock properties were received by Canada Zinc Metals Corp. The survey was designed to identify significant structural features and gravity high anomalies within the Gunsteel Formation shale. The data in conjunction with previously acquired airborne VTEM, soil geochemistry, and geologic mapping data is being used to further delineate target areas on the properties.
In 2017, Canada Zinc Metals Corp. received the final report on the structural interpretation of satellite imagery for the Akie and southern parts of the Kechika Regional project. The principal objective of this study was to generate exploration targets for SEDEX mineralization over a large regional framework in a cost-effective manner. The project involved an interpretation of a 6162-square-kilometre area centred between the Akie property (094F 031) 45 kilometres to the south and the Mount Alcock property to the north, and was undertaken at variable scales of 1:15,000 to 1:25,000 using Sentinel-2 and Landat-7 imagery. Fifty-centimetre-resolution Pleiades-1A data, centred on the properties, were interpreted in greater detail at up to 1:2500 scale. Landsat-7 imagery was also processed for hematitic and jarositic iron oxides, as well as generalized clay alteration.
