The Bend 1 Canyon Zone is located in the Cummins River canyon near the confluence of the Cummins River with the Columbia Reach on the east side of McNaughton Lake. The occurrence is a few kilometres from the now defunct Big Bend Highway and approximately 109 kilometres south-southeast of Valemount.
The area is underlain by a sequence of quartzites, carbonates and pelites of the Hadrynian Miette Group through the Lower Cambrian Gog Group to the Middle Cambrian Chancellor Group. The Gog Group is subdivided into three formations. From oldest to youngest these are: McNaughton Formation, 500 metres of basal quartzite; Mural Formation, 100 metres of marble, sandy carbonate, and shale; and the Mahto Formation, 10 to 200 metres of quartzite with minor pelite. The overlying Chancellor Group has two subdivisions; the Tsar Creek and Kinbasket formations. The Tsar Creek Formation consists of mainly pelite, up to 100 metres thick, with irregular lenses of sandy carbonate and quartzite up to 100 metres thick. The Kinbasket Formation consists of over 800 metres of sandy carbonate with lenses of grey marble, up to 200 metres thick.
Two phases of folding and metamorphism are recognized with metamorphism reaching amphibolite grade (biotite to sillimanite zone) resulting in a Barrovian sequence of isograds related to the first and major phase of metamorphism. Metamorphic temperatures in the area were determined to have reached up to 480 degrees Celcius at a pressure of approximately 5 kilobars.
The Porcupine Creek anticlinorium, a major regional structure trending northwest lies to the east of the prospect. The units strike southeast and dip steeply southwest. Thrusting is common in the area and to the west, the Purcell fault separates the Middle Cambrian Chancellor Group from Proterozoic Windermere Super Group rocks west of McNaughton Lake.
Stratiform mineralization of the Bend 1 Canyon Zone showing is exposed over approximately 100 metres in the canyon walls of Cummins Creek within the Tsar Creek Formation. Mineralization strikes southeast and dips 65 to 70 degrees south. Many layers in the Tsar Creek Formation are tightly folded with axial planes striking southeast and dipping steeply southwest. The main mineralized zone is 7 metres thick containing disseminated and massive sulphides. In decreasing order of abundance these are pyrite, pyrrhotite, sphalerite and galena with lesser arsenopyrite, chalcopyrite and magnetite in a siliceous matrix. The main zone is overlain by 6 metres of chocolate weathering, manganiferous dolomite with disseminations of pyrite, sphalerite and galena. Quartz-filled tension cracks are common. Mineralization is underlain by greater than 13 metres of intensely silicified, garnet biotite and garnet muscovite schist with minor pink quartzite. Quartz and sericite comprise this intense silicification. Exploration to date indicates a dip length in excess of 200 metres and a partially exposed strike length in excess of 400 metres (Assessment Report 16544).
The Bend prospect is a stratiform, synsedimentary, exhalative massive sulphide lens that was deposited within the unstable cratonic margin of Ancestral North America in the Hadrynian-Cambrian. Protoliths of the hostrock include shale, chert, pelitic chert, and manganiferous carbonate units consistent with deposition in a starved basin. The metalliferous-rich sediments were probably deposited from dense, metal-rich brines derived from compaction of the sedimentary pile (Fieldwork 1986). Upon reaching the seafloor, brines denser than the sea water pooled in a major depression. Other chemical sediments, such as iron and manganese-rich metacherts above the Bend occurrence, are commonly associated with the end of sulphide deposition (Fieldwork 1986).
Sampling from the south and uppermost exposure at 750 metres (high flood level of McNaughton Lake) yielded 2.1 metres grading 142 grams per tonne silver, 8.4 per cent lead and 2.0 per cent zinc (Assessment Report 16544). Some of the bands included at this location are 7 centimetres thick and yielded values of 130 to 615 grams per tonne silver, 3.5 to 5.0 per cent lead and 0.1 to 15.0 per cent zinc (Assessment Report 16544).
In 1992, results from diamond drilling by Teck Exploration Ltd. were encouraging. Of nine drillholes, TK-92-5, TK-92-8 and TK-92-12, intersected a relatively thick sequence of sulphide-bearing dolomite. At best, the mineralized horizon assayed 3.58 per cent zinc, 0.84 per cent lead and 14.97 grams per tonne silver over 5.24 metres (TK-92-5) which includes 0.35 metre of 8.50 per cent zinc, 1.78 per cent lead and 24.68 grams per tonne silver (Assessment Report 22635).
In 1949, mineralization was discovered during the construction of the Big Bend Highway and subsequently staked. In the subsequent years, the original claims were allowed to
lapse. In 1966, Cominco restaked 45 claims comprising the Ben 1-45 claim group and the following year Cominco drilled 240 metres in 13 short holes. In 1971, Laura Mines conducted further drilling with a total of 490 metres drilled in 4 holes. Subsequent work followed and in 1979 John Leask and Associates reinterpreted the mineral occurrence to be of a shale-hosted massive sulphide type, similar to the Howard’s Pass deposits. Work continued on the showing and area through the 1980s and into the early 1990s when Teck drilled 17 holes in 1991 and 1992 in an attempt to trace the mineralized horizon north and south along strike. No significant work has occurred on or around the Cummins River showing since this time.
In 2015, soil and rock sampling was conducted on the Cummins River property on behalf of Tsar Creek Holdings Ltd. The Cummins River claims covers the North Road showing (083D 002) and Canyon/Bend (083D 001, this description) showings. The ground work included the collection of 430 soil samples. Also in 2015, an airborne geophysical survey was completed on behalf of Tsar Creek Holdings Ltd. A total of 623 line kilometres of helicopter-borne electromagnetic (VTEM) geophysical data were acquired.
