The Silver Discovery, or Rhub, showing is situated immediately north of Sam Hardy Lake on the former Rhub 8 claim, approximately 1.7 kilometres north of Intata Reach, 10 kilometres east of the Barb showing and 70 kilometres south of Burns Lake.
The region is within the Intermontane Belt, underlain dominantly by Lower to Middle Jurassic volcanic and sedimentary rocks of the Hazelton Group. These assemblages are overlain by the Upper Cretaceous to Lower Tertiary Ootsa Lake Group and Miocene plateau basalt. Intruding Lower Jurassic rocks of the Hazelton Group in the northeastern part of the map sheet is a belt of granodiorite, diorite, and quartz diorite plutons of the Lower Jurassic Topley intrusive suite. Felsic plutons of probable Cretaceous age intrude both Lower and Middle Jurassic Hazelton strata. The region is very structurally complex due to the presence of two strong fault systems, one trending northwest and another trending northeast.
The Silver Discovery zone is an area of intensely argillic-altered Ootsa Lake volcanic rock containing epithermal gold and silver mineralization. Mineralization is microscopic in nature and associated with pyrite-marcasite and possibly native gold and silver within argillically altered (kaolinized) and silicified Ootsa Lake rhyolite flows and tuffs. Gold-bearing boulders were initially discovered and led to the subsequent delineation of several zones of silica flooding and argillic alteration. These zones occur within rhyolite and rhyolite tuff of the Upper Cretaceous to Lower Tertiary Ootsa Lake Group. A felsic flow unit is distinguished by the presence of perlite. The zones are composed of brecciated rhyolite healed by amorphous silica, a series of stockwork veins or amorphous silica with varying amounts of pyrite and marcasite. Complex geology and structure in the Silver zone area makes correlation of rock types and mineralization extremely difficult. The main controls on mineralization appear to be fracture intensity and the porosity of the hostrock. Though Rhyolite flows and tuffs are preferable hosts, mineralization does crosscut lithologies.
A second area of epithermal quartz veining and breccia with weakly anomalous gold values, referred to as the Quarry zone, is located south of Davidson Lake, approximately 4 kilometres east-southeast of the Rhub (Silver Discovery) zone.
Work History
The first documented work in the area was conducted in 1949 by H.W.Tipper of the Geological Survey of Canada.
In 1980, Guichon Explorco Limited conducted exploration work in the area. Guichon Explorco staked the Mar claims over an area of epithermal gold potential. Two zones of epithermal alteration were identified based on rock-chip samples that returned elevated levels of arsenic, mercury, and minor gold. In 1983, a further program of soil sampling was completed.
In 1985, Hudson Bay Exploration (later known as Mingold Resources Incorporated) followed up on the work conducted by Guichon Explorco and conducted an examination of the Mar claim area. Several samples of chalcedonic quartz float with anomalous gold values were found in the area of the former Mar 11 claim. One sample of chalcedonic quartz float collected from the Rhub 4 claim area returned an assay of 0.07 gram per tonne gold (Assessment Report 21952, p. 5). The following year, Mingold Resources staked the Rhub 1 to 13 and Barb 1 claims over a region covering the mineralized area identified by Guichon Explorco and an area of anomalous gold values in rock identified by Mingold Resources. Prospecting in the area of the former Mar 11 claim resulted in the discovery of the Silver zone.
In 1987, Mingold Resources Incorporated carried out a program of soil and rock-chip geochemical sampling and trenching on the Barb and Rhub claims. In total, 2452 soil samples (including 226 samples from the Silver Discovery grid) and 153 rock samples were collected from the property. A 280 by 100-metre zone of anomalous (1 gram per tonne; Assessment Report 16593, p. 7) silver in soil was outlined on the Silver Discovery grid. The anomaly was partially coincident with an area of anomalous gold returning values up to 0.154 gram per tonne gold (Assessment Report 16593, p. 7). As a follow-up, seven trenches were dug on the Silver Discovery grid. Trench MBHT-6, dug in 1987, returned an average of 0.583 gram per tonne gold and 161.49 grams per tonne silver over 7 metres, including 3.5 metres with 0.891 gram per tonne gold and 224.57 grams per tonne silver (Assessment Report 18189, p. 12). Four samples (4137 through 4140) of subcrop from the Silver zone yielded from 0.165 to 0.220 gram per tonne gold and 90.0 to 607.4 grams per tonne silver (Assessment Report 16593). Later reports, in 1988, indicate samples yielded up to 7.15 grams per tonne gold and 610.8 grams per tonne silver (Assessment Report 18189).
Later in 1987 and continuing into 1988, Mingold Resources carried out a program of drilling and trenching. As a result, 16 reverse circulation drill holes totalling 1159.5 metres, including six drillholes totalling 579.1 metres in the Silver zone, were completed on the property. Three holes—SRH-4, 5 and 6—intersected the mineralized zone. Holes SRH-5 and SRH-6 tested an east-west–trending vein system. Both holes intersected several sections of low-grade silver (less than 34.3 grams per tonne; Assessment Report 18189, p. 13) and significant silica breccia and pyrite but did not encounter any economic grades of mineralization. Hole SRH-4 tested a north-south trend and intersected two zones of silver and gold mineralization. The upper and lower zones of mineralization yielded 37.4 and 36 grams per tonne silver with 0.34 and 2.33 grams per tonne gold over 3.05 and 4.57 metres, respectively (Assessment Report 18189).
In the summer of 1988, six NQ diamond drill holes totalling 1036.9 metres were completed in the Silver zone. Five holes were drilled to test a north-south–trending mineralized fault zone identified in Trench MBHT-6. Only two of the five holes (SRH-9 and SRH-11) intersected significant mineralization. Hole SRH-8 was drilled to intersect the east-west–trending vein system encountered the previous year in holes SRH-5 and SRH-6 and intersected five mineralized zones. Significant results from the 1988 drill program include drillhole SDH-9, with 7.17 grams per tonne gold and 27.8 grams per tonne silver over 1.52 metres and 1.34 grams per tonne gold and 5.83 grams per tonne silver over 1.22 metres; drillhole SDH-11, with 0.41 gram per tonne gold and 45.6 grams per tonne silver over 1.52 metres and drillhole SDH-8, with 0.034 to 0.068 gram per tonne gold and 42.17 to 203 grams per tonne silver over five separate 1.52 metre long sections (Assessment Report 18189, p. 14).
Further, in 1988, 1500 soil samples, including 48 from the Silver Discovery zone, were collected but did not return any significant results. A very low-frequency electromagnetic survey totalling 27.5 line-kilometres was completed and confirmed the presence of anomalies detected during the 1987 reconnaissance survey. Six trenches were dug in the Silver zone, but only three reached bedrock.
In 1989, on behalf of Alta Ventures Incorporated, Target Surveys Incorporated completed an induced polarization resistivity geophysical survey of the area and identified ten anomalous zones. In 1991, Equity Silver Mines optioned the Rhub-Barb property from Mingold Resources Incorporated and completed a program of diamond drilling and road building. Five diamond drill holes totalling 943 metres were completed over a 400-metre strike length on the J-anomaly, situated immediately north of the Silver zone and identified the previous year. Drilling intercepts included 0.25 gram per tonne gold and 71 grams per tonne silver over 2.89 metres in hole RB91CH-02, 64.0 grams per tonne silver over 2.11 metres in RB91CH-03, 1.03 grams per tonne gold over 0.02 metre in hole RB91CH-04 and 0.13 gram per tonne gold over 8.85 metres in hole RB91CH-05 (Assessment Report 21952).
In 1992, Cogema Resources Limited conducted a regional till geochemical sampling and prospecting program over the entire Nechako Basin.
In 1994, the area was prospected and sampled as the Ana claims by J.G. Dawson. A sample (GD11) from the Silver Discovery zone yielded 0.56 gram per tonne gold and 8.7 grams per tonne silver (Assessment Report 23904).
In 2003, Southern Rio Resources Limited staked the Sam claims to cover the Rhub epithermal gold-silver showing. A total of 16.2 line-kilometres of ground magnetometer and very low-frequency electromagnetic geophysical surveys were performed on the Sam #3 claim to the immediate south of the Silver zone showing. Readings were taken at 12.5-metre intervals along east-west cut gridlines.
In 2006, Goldmember Ventures Corporation conducted a regional geophysical study program that involved reprocessing existing geophysical data and producing new three-dimensional inversion maps.
In 2015 and 2016, John Kreft completed programs of prospecting and biogeochemical and geochemical (rock and soil) sampling on the area as the GRG claims. A sample (AGR-07) of rhyolite breccia yielded 1.12 grams per tonne gold and 79.4 grams per tonne silver (Assessment Report 35611).
