On the Iron Vault claim the host rocks consist of dark green and red andesites with some interbedded tuffs separated from a series of greenish tuffs by a band of fossiliferous limestone. These rocks are part of the Lower Jurassic Hazelton Group, Nilkitkwa Formation. The tuffs are mostly fine-grained and massive, but some beds are well laminated with bedding, striking east and dipping from nearly vertical to 50 degrees north. The top of the series is believed to be north so where the beds dip to the north or northeast, the strata are overturned. These rocks are intruded by a 120 to 300 metre by 900 metre granodiorite stock which outcrops on the south end of the Iron Mask claim and extends west across the Copper Queen and Lily Fraction claims, all part of the Silver Creek Group. The limestone band is cut off to the west by the granodiorite stock. The limestone unit is lenticular in outline, attaining a maximum width of 20 metres. Mineralization occurs as lens-shaped pods consisting of pyrrhotite, sphalerite, and pyrite replacements in the limestone. Mineralization appears to be localized to zones where small faults crosscut the limestone. However, recrystallization and flowage have absorbed differential movement within the unit so that fissures do not penetrate the unit very deeply. Therefore, the orebodies occur along the contact and are characteristically short and lenticular in surface outline, but may be pipe-shaped.

Along the south side of the limestone contact with green tuffs, a lenticular sulphide body, approximately 15 metres long and 5 metres wide, consists of about 40 per cent black sphalerite, 40 per cent pyrrhotite, and 10 per cent pyrite. Other sulphide lenses are exposed in open-cuts along the north side of the limestone band and occur along small faults both as fissure fillings and as replacements in the wall rocks.

A calcite vein occurs along a fault with vertical displacement in the andesitic rocks. It consists of sheared and brecciated andesite cemented by calcite with varying amounts of galena, sphalerite, tetrahedrite, arsenopyrite, and pyrite. The fault has a curving strike, changing from 210 to 260 degrees, and dips from 55 to 65 degrees southeast. At elevation 1720 metres, the fault is bordered on the south side by limestone 15 metres in width. The limestone has been heavily replaced along the fault by massive sulphides to form a lenticular orebody 9 metres long and 5 metres wide. The sulphides are present in the following order of abundance: pyrite, sphalerite, galena, arsenopyrite, pyrrhotite, and chalcopyrite.

The best mineralization occurs east of the fault along the east edge of the limestone body. A representative sample of the ore, containing about 10 per cent sulphides, assayed: 0.34 gram gold, 215.7 grams per tonne silver, 2.04 per cent lead, and 3.5 per cent zinc (Minister of Mines Annual Report 1926, page 129).

Production in 1964 consisted of 3,235 grams silver, 663 kilograms lead, and 71 kilograms zinc.

WORK HISTORY

Exploration work on the Silver Creek group from about 1907 was done in open cuts, stripping, and a 7.6 metres adit. In the fall of 1910 the property was bonded to the Hudson Bay Mountain Mining Company, Limited, of which there is no record as a Canadian incorporation. Work by the company included open cutting, a 5.5 metre shaft, and 2 adits 24 and 41 metres in length. In 1912 a long crosscut was begun some distance below the mineralized outcrops and was driven 122 metres. The bond was given up in 1914.

Five claims, the Iron Mask, Copper Queen, Texada, Iron Vault and Van Anda (Lots 5750 R5-5752 R5, 5754 R5, and 5756 R5, respectively) were Crown-granted in 1914 to Peter Schufer and Leeman Wood.

The owners resumed further work on the property in I916 and continued into 1919. A short adit was driven on the calcite vein and small shipments of sorted ore were made in 1917 and 1918.

Late in 1925 The British Canadian Silver Corporation Limited, optioned the property and development work began in 1926. Considerable trenching was done, and some 55 metres of drifting and crosscutting in No. 3 adit. Work ceased late in the fall of 1926 and the option was subsequently given up. The Lily Fr. (Lot 7245), adjoining the Iron Vault on the west, was Crown-granted in 1930 to Peter Schufer.

R.W. Wilson & Sons, of Great Falls, Montana, optioned the Silver Creek and adjacent groups in about 1930. No activity was reported on the Silver Creek group until 1935 when further work was done in No. 3 adit.

Sil-Van Consolidated Mining and Milling Company, Ltd., incorporated in September 1950, acquired a number of properties on Hudson Bay Mountain, including the Silver Creek group. The company name was changed in 1957 to Sil-Van Mines Limited, with Silver Standard Mines Limited acquiring a 36.5 per cent interest in the company. In August 1963 Sil-Van incorporated a new company Hudson Bay Mountain Silver Mines Ltd., to which it transferred the Silver Creek and adjacent properties. During 1965-66 the company extended No. 3 adit 158 metres. Diamond drilling in 1905 was done in 16 holes totalling 1024 metres; 8 of the holes were apparently drilled on the Silver Creek group and the remaining on the adjacent Silver Lake group. Diamond drilling totalling 217 metres in 7 holes done in 1966 in No. 3 adit and the low level crosscut.

The company name (Sil-Van) was changed in April 1969 to Dorita Silver Mines Ltd. At that time the company held a 90 per cent in the Silver Creek property.