The Benson Lake Mine (Independence occurrence) is located northwest of Merry Widow Creek, approximately 200 metres southwest of the creek mouth on the Benson River.

Regionally, the area is underlain by basaltic volcanic rocks of the Upper Triassic Karmutsen Formation (Vancouver Group) which are overlain by limestone of the Upper Triassic Quatsino Formation (Vancouver Group), limestone, mudstone and siltstone of the Upper Triassic Parson Bay Formation (Bonanza Group) and mixed volcanic and sedimentary rocks of the Lower Jurassic LeMare Lake volcanic unit (Bonanza Group), respectively. The volcanic and sedimentary rocks have been intruded by gabbro to quartz diorite of the Lower to Middle Jurassic Island Plutonic Suite.

The Independent occurrences and Benson Lake mine are a continuation of the "Old Sport Horizon" (Geological Survey of Canada Bulletin 172, page 80) and underground workings are connected with the Old Sport mine (092L 035).

The mineralization occurs along the conformable contact between Upper Triassic Vancouver Group rocks comprised of Karmutsen Formation andesite and overlying Quatsino Formation limestone. These rocks strike northwest and dip 37 degrees west where they are in contact with the gabbro-diorite "Coast Copper Stock" of Jurassic Island Plutonic Suite. Mafic dykes have intruded the volcanics and sediments.

The mineralized horizon has been traced for over 2.5 kilometres to the Old Sport mine and ranges from 0.6 to 30 metres in width. The horizon is comprised mainly of garnet, epidote, calcite and magnetite with minor diopside, actinolite and chlorite. Some quartz veins are present, mostly in the footwall. Chalcopyrite and bornite, and locally pyrrhotite and pyrite with arsenopyrite, form lenses, veins, tabular bodies, and disseminations in the silicates and magnetite.

Gold and silver are associated with chalcopyrite. Average grade of ore mined during 1968 and 1969 was 0.98 gram per tonne gold, 7.59 grams per tonne silver and 1.92 per cent copper.

Measured and indicated reserves are 272,154 tonnes grading 1.0 gram per tonne gold, 1.6 per cent copper and 30.0 per cent iron. The reserves are based on 1990 work and may have been included with the Merry Widow deposit (092L 044), but may be related to this property (N.C. Carter, personal communication, 1991).

During 1960 through 1973, the Coast Copper and Benson Lake mines produced 2,621,131 tonnes of ore yielding 90.8 90814 tonnes of copper, 377165 kilograms of silver, 3526.3 kilograms of gold and 507,207 tonnes of iron (Assessment Report 28863).

Work History

The area has been explored in conjunction with the Merry Widow (MINFILE 092L 044) deposits since the early 1900’s. During 1960 through 1973, Coast copper developed and mined the Benson Lake property. In 1968, Quatsino Copper Gold completed a program of airborne magnetic and radiometric geophysical surveys on the area. In 1970, Alice Lake Minerals completed an aeromagnetic survey. During 1989, through 1992, Taywin Resources completed programs of geological mapping, trenching and surface sampling on the area.

During 2005 through 2012, Grande Portage Resources completed programs of rock, silt and soil sampling, geological mapping, airborne electromagnetic and magnetic surveys and a ground magnetometer survey on the area. In 2012, Grande Portage Resources Ltd. completed a program of prospecting and rock sampling on the area. In 2016 and 2017, Bridgeland Minerals completed a radar satellite and LIDIR orthophoto geological interpretation program on the area as the Blue Gold/Merry Widow property. In 2019, Mirva Properties Ltd. completed a rock sampling program on the Merry Widow property. In 2020, Roughrider Exploration Ltd. completed a program of rock, silt and soil sampling on the area as the Empire Mine property.