High grade vein material

Virtual Museum ID: 19-NC-03

Specimen Summary


consisting of quartz, argentite and native Ag. This was collected from dump material below one of the production headings dating back to the 1920s.

Specimen Data

 

The information listed below relates to the current holding location or collection that the sample is from, and whether the item is viewable at that location or is part of a private collection. Coordinates are given as guides, and we remind you that collecting specimens from these locations is not allowed. Caution is advised visiting such sites and Below BC assumes no responsibility for any injuries or trespassing charges that may occur as a result of the viewer entering these sites.

Collection Details

Original Collection:

Smithers Exploration Group (SEG)

Sub Collection:

DR. N.C. (NICK) CARTER ROCK COLLECTION #1

Collection ID:

NC-03

Virtual Museum ID:

19-NC-03

Accessibility:

Date Added to VM:

2019-08-20

Location Information

Sample Origin:

Alice Arm, B.C.

Specific Site:

Dolly Varden Mine

UTM Easting:

467897

UTM Northing:

6170769

Datum:

09 (NAD 83)

Coordinate Accuracy:

Specimen Details

VM Category:

Rock

Primary Features:

High grade vein material

Primary Mineral Formula:

Primary Category:

Secondary Features:

Advanced Geological Information

 

The following section provides geological data relating to the specimen or the site it was collected from, when available. Information has been obtained from various sources including private and government datasets but may not be up to date. Any geological time periods or ages listed often relate to the primary geology of the area, and may not be the actual date of an event such as mineral formation.

Geological Formation:

Stuhini Group/Hazelton Group

Geological Period:

Upper Triassic/Lower-Upper Jurassic

Stratigraphic Age:

Geological Belt:

Stikine

Geological Terrane:

Intermontane

Minfile ID:

103P 188

Site Details:

The Dolly Varden mine is located 300 metres west of the Kitsault River, 22.5 kilometres north of Alice Arm. The mine produced high grade silver ore periodically between 1919 and 1940.

The region is underlain by an assemblage of volcanics and sediments comprising the Upper Triassic Stuhini Group and the Lower-Upper Jurassic Hazelton Group. These are folded into a doubly plunging north-northwest trending syncline and have been regionally metamorphosed to greenschist facies.

The orebody consists of a stratiform volcanogenic silver-zinc-lead barite exhalative horizon which is underlain by andesitic crystal vitric (shard) tuff and overlain by andesitic ash tuff of the Hazelton Group. These units have undergone sericitization, silicification and propylitization due to regional metamorphism and hydrothermal alteration.

The deposit lies on the steeply dipping west limb of the Kitsault River syncline. The deposit has been segmented by a series of north to northeast striking reverse and normal faults into at least 13 minor blocks, 9 to 52 metres in length, which make up four major fault blocks. These faults dip 30 to 60 degrees west and horizontal displacements vary from 15 to 50 metres.

The deposit is divided into two main segments, the Dolly Varden East, containing the two eastern major blocks, and the Dolly Varden West, which contains the two major western blocks. The Dolly Varden East orebody strikes east to northeast for 200 metres and the Dolly Varden West orebody strikes west-northwest for 450 metres. The total strike length of the entire deposit is 650 metres. The deposit, 1 to 9 metres in width, dips 40 to 60 degrees north and extends downdip for at least 790 metres.

Mineralization in the Dolly Varden East deposit consists of disseminated to massive pyrite, minor chalcopyrite and traces of argentite, pyrargyrite and native silver in a gangue of milky white quartz and minor sericite. This quartz-sulphide exhalite is commonly found interbedded with hangingwall tuffs. The mineralization is reported to average 865 grams per tonne silver (Devlin, 1987).

The Dolly Varden West orebody consists of layers, disseminations and stringers of sphalerite and galena and minor pyrite, chalcopyrite and tetrahedrite and trace of native silver in a gangue of calcite, quartz, siderite and barite. This carbonate-sulphate-sulphide exhalite is reported to average 15 grams per tonne silver (Devlin, 1987).

Combined (proven, probable) reserves at Dolly Varden are 42,633 tonnes grading 754.1 grams per tonne silver (George Cross News Letter May 25, 1989).

Between 1919 and 1940, 33,434 tonnes of ore with an average grade of 1269.69 grams per tonne silver, 0.09455 per cent copper and 0.4599 per cent lead were mined from the Dolly Varden East orebody. See Torbrit (103P 191) for more details.

In 1910, the first staking in the Dolly Varden area occurred with the location of the Red Point No. 1 mineral claim (103P 010, 196). In 1911, the first claims for silver in the Dolly Varden mine area were staked. The Sportsman and North Star (103P 189) were staked in 1912 and 1914, respectively. Extensive prospecting, test pitting and drifting was carried out over the next seven years to develop the Dolly Varden silver deposit and bring it to production in 1919. The only other deposit in the area to see production was the Torbrit (103P 191). During production at the Torbrit, exploration and development continued on the North Star and Wolf (103P 198) prospects. Lesser amounts of exploration were conducted on the Moose-Lamb (103P 008), Tiger (103P 194) and Surprise (103P 185) showings.

From 1969 to 1973, Dolly Varden Mines Ltd. conducted surface exploration and diamond drilling on other quartz-barite prospects in the area. From 1979 to 1981, Dolly Varden Minerals Inc. commissioned consultants Derry, Michener and Booth to conduct diamond drill exploration and ore reserve calculations of the silver deposits. In 1986, B. Devlin, working on behalf of Derry, Michener, Booth and Wahl, and Dolly Varden Minerals Inc., recognized the probable volcanogenic origin of the Dolly Varden-North Star-Torbrit silver deposits. In 1989, Dolly Varden Minerals Inc. initiated a comprehensive, multistaged surface exploration program that included 2256 metres of drilling on the Red Point and Red Point Extension showings (103P 010, 196) along with detailed geologic mapping and geochemical sampling of a limited area of the 'Gold Belt' alteration. In conjunction with this work, Dolly Varden Minerals conducted a surface diamond drilling program on the North Star deposit (103P 189) consisting of 2397 metres in 6 holes to verify drilling done by Torbrit Silver Mines Limited in 1957. The program confirmed the previous results and indicated the presence of an extensive volcanic exhalative horizon. In 1990, Dolly Varden Minerals Inc. conducted geological mapping and diamond drilling. The drill program was conducted on portions of the North Star, Dolly Varden and Torbrit deposits and the V zone (103P 010, 18, 196) and totalled 7096 metres in 18 holes.

In 2010, Dolly Silver Corporation conducted an exploration program on the Dolly Silver property which consisted predominantly of a detailed stream sediment sampling survey with associated geological mapping, prospecting, rock and soil sampling. A total of 81 rock samples, 19 soil samples and 150 stream sediment samples were collected. A concurrent helicopter-borne time domain electromagnetic (VTEM), magnetic and radiometric survey over both the Dolly Silver and Dolly Varden properties was also completed. Flight line spacing was 200 metres over the Dolly Silver property and 100 metres over the Dolly Varden property with a total of 941.7 line kilometres of data collected.

In 2013-14, Dolly Varden Silver Corporation completed 5280 metres of diamond drilling in 12 holes, geology, geochemistry (2500 soils), geophysics (induced polarization (IP) and electromagnetic (EM), 10.9 line kilometres), and two boreholes (IP plus EM).

In 2015, Dolly Varden Silver Corporation delivered a maiden mineral resource estimate for the Dolly Varden silver project. The project area encompasses several past-producing mines and mineral occurrences which were explored in two phases of exploration during 2015. Phase one consisted of extensive groundwork and included geological mapping, prospecting, lithogeochemical rock sampling and soil sampling. Data acquired during phase one helped define drill targets for the second phase. Drilling totalled 2037 metres in ten diamond-drill holes. Three holes targeted the volcanogenic massive sulphide prospective Trout Horizon at the Ace-Galena showing (103P 208) located about 6 kilometres north of the Dolly Varden deposit.

In 2016, Dolly Varden Silver Corporation carried out surface mapping and sampling and completed 2311 metres of diamond drilling in 13 holes. Diamond drilling was carried out on the Torbit deposit (103P 191) and in the Ace-Galena area (103P 208).

In 2017, Dolly Varden Silver Corporation announced plans for 12,000 metres of diamond drilling at the Dolly Varden silver project. The project consists of the Torbrit (103P 191), Dolly Varden, Wolf (103P 198), and North Star (103P 189) deposits. Drilling discovered an eastern fault offset of the Torbrit deposit (Torbrit East, 103P 190), with assays including 13.00 metres (9.96 metres true thickness) grading 244.8 grams per tonne silver, 0.14 per cent lead and 0.09 per cent zinc. Within this interval was 5.00 metres (3.83 metres true thickness) grading 481.9 grams per tonne silver, 0.21 per cent lead and 0.12 per cent zinc (Information Circular 2018-1, page 137).

A maiden National Instrument 43-101 mineral resource estimate was announced in August, 2015, covering the four historical deposits on the property: Torbrit, Dolly Varden, Wolf and North Star. The total estimated mineral resources for the four deposits are 3.073 million tonnes Indicated at 321.6 grams per tonne silver, and 898,500 tonnes Inferred at 373.3 grams per tonne silver (Press Release - Dolly Varden Silver Corp., November 23, 2016; Information Circular 2018-1, page 129).

Additional Images