Dolly Varden Mine, Alice Arm, Skeena Mining Division, British Columbia, Canadai

Regional Level Types
Dolly Varden Mine	Mine
Alice Arm	Village
Skeena Mining Division	Division
British Columbia	Province
Canada	Country

The Dolly Varden mine is located 300 metres west of the Kitsault River, 22.5 kilometres north of Alice Arm, British Columbia. The mine produced high grade silver ore periodically between 1919 and 1940.
The following quote is from B.C. Government site “Minfile”- Minfile No. 103P 188, current to 2020:
“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).”

Comments by Giles Peatfield regarding some of the minerals reported:
It is important to note that the list below is minerals that have been reported by various workers, as far back as 1914. Some of these are questionable, as will be explained below. Minerals not dealt with in these comments have been reported by numerous workers as common.
Acanthite: McMullan (1916) reported “brittle silver”; all subsequent workers reported “argentite”.
Argyrodite: This rare silver-germanium sulfosalt was described by Soles (1952) and confirmed by X-ray analysis by Thompson (1953).
Arsenopyrite: This was reported by Forbes (1914), but not seen by any subsequent worker. I regard it as tentative at this locality.
Baryte: All workers up to the present have referred to this with old name “barite”.
Cerargyrite: This was reported by McMullan (1916), but not seen by any subsequent worker. I regard it as unlikely at this locality.
Cerussite: This was reported only by Soles (1952), but his description is detailed and I am inclined to accept this as valid for the locality.
Pearceite: This was first reported by Hanson (1922b) and reiterated by him (1935), with no detailed data. Burden (1940) also reported pearceite, but gave no data. I find it telling that the mineral was not reported by Thompson (1953), and for this reason I regard its occurrence as tentative at best.
Polybasite: This was reported by Soles (1952), on the basis of microscopic work, and was subsequently reported by Thompson (1953) based on Soles’ work. For this reason I believe it to be a valid occurrence.
Proustite: This was initially reported by Hanson (1922b). McKnight (196?) also reported proustite, but the marker of the report (R. M. Thompson?) would appear not to have been sure of this identification, and rather accepted McKnight’s tentative polybasite. I would regard proustite as tentative at best.
Pyrargyrite: This has been reported by numerous workers and should be regarded as valid.
Manganese minerals: Hanson (1922b) reported something that he thought might be either rhodochrosite or rhodonite, but gave no further information. No other workers have reported either mineral. Although one or the other (or both) are possible, I have not included them in the list of minerals reported.
Tetrahedrite: This has been reported by many workers. Soles (1952) described it, and made the following comment: “An X-ray photograph of the mineral was taken by Dr. R. M. Thompson who noted that the unit cell was extremely large; this fact suggests that the tetrahedrite is a highly argentiferous variety, although no silver was detected in microchemical tests.” We can be sure that there is tetrahedrite, but not that it is necessarily the high-silver variety.
Further to the discussion, it should be noted that in the early years, there was considerable debate as to whether or not the rich silver minerals were hypogene or the result of supergene processes. Warren and Brown admirably summarized this debate, and came to the conclusion that “. . . except for a large part of the native silver, the rich silver ore is hypogene in origin.” Dunne and Pinsent (2002) studied liquid inclusions, but unfortunately this work did not include any of the silver minerals so could not add to the discussion.

Other Databases

Link to British Columbia Minfile:	103P 188

Other Regions, Features and Areas containing this locality

References