The Black Jack occurrence is located about 550 metres south of Barkerville, 92 kilometres east of Quesnel.
The Barkerville property of Williams Creek Exploration consists (in 2006) of 28 Crown-granted claims straddling two of the most productive streams of the Cariboo Gold Rush, Williams Creek (093H 119) and Stouts Gulch (093H 120). The claims include the historic Black Jack, Homestake, Cornish, and Wintrip claims, which are among longest continually maintained Crown grants in British Columbia, first recorded in the 1870s. The first record of production occurred during the late 1870s with a few hundred tonnes of ore being produced from the Black Jack vein. In 1933, Britannia Mining and Smelting Company optioned the claims and completed five short adits (237 metres) and a limited amount of diamond drilling before the property was dropped. In 1946, Williams Creek Quartz Mining completed diamond drilling and geological mapping of the property.
The Black Jack deposit lies within the Barkerville Terrane of the Omineca Belt. The Barkerville Terrane is in thrust contact with Triassic Quesnel Terrane rocks to the west and Hadrynian to Lower Paleozoic Cariboo Terrane rocks to the east. The Barkerville Terrane in this region is underlain by the dominantly metasedimentary rocks of the Hadrynian to Lower Paleozoic Snowshoe Group. In this area, the Snowshoe Group comprises limestone, phyllite and quartzite. These rocks have been regionally metamorphosed to greenschist facies.
Mineralization occurs in eight major quartz veins, bedded replacement-type zones and disseminated throughout the favorable horizon. These are variably mineralized with galena, pyrite, arsenopyrite and occasionally siderite. Gold is associated with sulphide mineralization.
In 1948, a 60-centimetre chip sample across one vein assayed 97.7 grams per tonne gold (Bulletin 38). In 1991, drilling on this vein by Williams Creek Explorations Ltd. failed to produce significant assays. The best intersection from this drilling program, from another vein, was 8.57 grams per tonne gold over 3.9 metres (George Cross Newsletter No. 210, October 31, 1991).
Minor production (180 tonnes grading 29.14 grams per tonne gold) was reported from the Black Jack deposit in the late 1800s (George Cross Newsletter No. 210). Old workings consist of the Westport, Wintrip and Black Jack adits.
Drilling by Williams Creek Explorations Limited in 1947 and 1991 indicated a mineral inventory of approximately 1250 kilograms of gold contained in 75,000 tonnes grading 16 grams per tonne gold along a strike length of 60 metres and to a depth of 125 metres (Property File - see Island Mountain (093H 006), Gold City Mining Corporation Information Brochure).
The Black Jack, Westport and Wintrip adits were investigated in 1973. This included washing and geological mapping of all three adits and sampling of the Westport adit. Nine of these samples contained native gold and assayed as high as 265.22 grams per tonne gold (Property File Placer Dome - Buchanan, K.J., 1973).
Gold City Mining Corp. optioned the property in 1995 and carried out trenching and a four-hole drill program. In 2003, Williams Creek Explorations performed a five line induced polarization (IP) geophysical survey and drilled 1007 metres in five holes in the hopes of intersecting the southeasterly continuation of the high-grade Bonanza Ledge gold replacement zone (093H 140), located approximately 2 kilometres on strike to the northwest. The program was designed to test geophysical anomalies generated by the IP program. Drilling intersected significant gold values, including a 1.2 metre interval of pyritic argillite and quartz vein that yielded 156.4 grams per tonne gold (www.williamscreekexplorations.com).
In 2005, Williams Creek returned to its Westport mesothermal gold vein prospect after a one-year hiatus and drilled 1460 metres in six holes. Several encouraging intersections resulted from the program including a 38.6 metre interval in drillhole 05-01 that averaged 2.6 grams per tonne gold; the intersection was heavily influenced by a 0.68-metre quartz vein that assayed 86.8 grams per tonne gold (Exploration and Mining in British Columbia 2005, page 52).
In 2011, Williams Creek Gold Ltd. completed phase II of its exploration and diamond drilling program on its wholly owned group of Crown-granted mineral claims which are concentrated in the Stouts Gulch and Williams Creek drainages. A total of 4819 metres were drilled in phase II, with an overall total of 9745 metres in 42 holes for the year. The program was designed to follow up on excellent initial intercepts from the 23-hole phase I drilling in both the Stouts Gulch area and the Morning Star area (093H 034) farther northwest.
The majority of the high-grade intercepts in the phase II drilling are quartz veins, locally in what appear to be vein zones. In hole WCX-11-26 in the Morning Star area, an interval of 25.1 metres contains enough high-grade veins and wallrock mineralization to average 4.59 grams per tonne gold from 258.1 to 283.2 metres (Press Release – Williams Creek Gold Ltd., January 18, 2013).
The area where the north trending Sirius fault extends through the confluence of Williams Creek and Stouts Gulch is the site of some of the better intercepts, some of which are near the surface. Drillholes WCX-11-38 through WCX-11-40 were collared approximately 61 metres east of the strong intercepts encountered in phase I holes WCX-11-01 through WCX-11-06 in the area of the Westport adit (093H 027). These holes contain numerous high-grade intercepts up to 1.3 metres at 39.6 grams per tonne gold. Ground preparation caused by deformation within the zone bounded by the Sirius fault and the Barkerville fault is thought to account for the better intercepts in this area.
