Virtual Museum ID: 19-BCGS-LGT1
Tungsten or wolfram(W) has the highest melting point(3,422 °C) and boiling point(5,555 °C) of all elements. Its important ores include Tungsten, scheelite, wolframite, hence the elements alternative name. Used include light bulb filaments, x-ray tubes and welding to name a few.
Scheelite is an important ore mineral for tungsten. It is very nice to look at under short wave ultraviolet light due to its fluorescence. It can be many different colours, but it is always somewhat translucent if not transparent and when in good crystal form can be used as a gemstone.
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.
Original Collection:British Columbia Geological Survey (BCGS)
Virtual Museum ID:19-BCGS-LGT1
Date Added to VM:2019-05-07
Sample Origin:127km NE of Atlin, B.C.
Specific Site:Logtung deposit
Datum:09 (NAD 83)
Primary Features:Tungsten Ore
Primary Mineral Formula:W
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:Nisling Assemblage
Geological Period:Early Cretaceous
Stratigraphic Age:145 - 100.5 Ma
Geological Terrane:Dorsey, Plutonic Rocks
Minfile ID:104O 016
The Northern Dancer claim is part of the Logtung property, which also includes adjoining claims in Yukon Territory, located about 127 kilometres northeast of the community of Atlin. Both sets of claims are owned by Strategic Metals Ltd. (ca. 2005). The Northern Dancer claim covers the southerly portion of a large mineralized system that includes the Logtung tungsten-molybdenum deposit located in the Yukon portion of the property. Access to the property is provided by a 13 kilometre gravel road extending from Kilometre 1203 on the Alaska Highway. Although the road has not been maintained since the early 198Os, it is passable with four-wheel drive vehicles during summer and fall.
The Logtung deposit located on the Nisutlin Plateau in northern British Columbia is associated with Early Cretaceous monzonitic granite of the Logtung stock and a Cretaceous felsic dike complex which have intruded hornfelsed metasediments of the Paleozoic to Proterozoic Nisling Assemblage. The sediments, which notably lack carbonates, consist of graphitic argillites and quartzites, phyllites, dolomite and limestone.
Several phases of fracture-hosted mineralization are related to multiple intrusive events. Early quartz-molybdenite-scheelite veins are related to a monzonitic granite intrusion and occur along the west flank of the Logtung stock for a distance of 1.5 kilometres. Later quartz-pyrite-scheelite veins are spatially and genetically related to a felsic dike complex north of the British Columbia-Yukon border. Finally, a 4.5 by 1.0 kilometre area of polymetallic sheeted veins trends northeast, on both sides of the border, and is centred on the felsic dike complex. This system is zoned from quartz, beryl, scheelite, chalcopyrite, bismuthinite and molybdenite, with wolframite and fluorite veins occurring in the southwest part of the zone to lead-zinc-silver veins with abundant arsenopyrite and minor tin in the northwest (north of British Columbia-Yukon border).
Pervasive hydrothermal alteration is not widespread; silicification occurs as limited vein halos which form larger zones in areas of high vein density. Hornfelsing and skarning of surrounding sediments preceded hydro-fracturing and vein and breccia mineralization indicating the porphyritic nature of the deposit. Garnet-diopside alteration halos around quartz-molybdoscheelite veins; biotite and hornblende alteration zones occur around polymetallic sheeted zones in the southwest region of the deposit. The Logtung monzogranite stock is younger than expected, a previous Rb/Sr date on possible the same unit is 110 +/- 2 Ma.
Mineralization is associated with an elongate dome with an axial trace trending northeast, parallel to the strike of the north flank of monzogranite. Bedding in the sediments strikes northeast.
Unclassified reserves at Logtung are 162 million tonnes grading 0.03 per cent molybdenum and 0.1 per cent tungsten (CIM Special Volume 37, page 274).
On April 10, 2008, Largo Resources Ltd. announced updated indicated resources of 140.8 million tonnes grading 0.10 per cent WO3 and 0.026 per cent Mo and inferred resources of 253.2 million tonnes grading 0.10 per cent WO3 and 0.022 per cent Mo, both using a cut-off grade of 0.06 per cent WO3 (Press Release - April 10, 2008, www.sedar.com).
On March 12, 2009, Largo announced updated resources:
In 1975, the Bath Uranium Partnership discovered tungsten stream sediment anomalies, but it was not until the following year that the anomalies were traced to their source and a large claim block was staked straddling the British Columbia-Yukon border. After preliminary prospecting, ownership of the claims was transferred to Logjam Resources Ltd. which immediately optioned them to Amax Potash Limited. Between 1977 and 1981, Amax built a road to the property and explored with geological mapping, soil geochemistry, induced polarization surveys, 51 diamond-drill holes totalling 11,157 metres and 496 metres of underground workings. The surface work was done on both sides of the border but only 474 metres of diamond drilling (four holes) were performed on British Columbia claims. Most of the work focussed on an area about 300 metres north of the border where the Logtung deposit was outlined. In 1983, Amax transferred its interest to Canamax Resources Inc. which then prepared a preliminary feasibility study that concluded the deposit was uneconomic. In 1984, airborne magnetic and electromagnetic surveys were conducted. Canamax dropped its option in 1986. Subsequently most of the Yukon and all of the British Columbia claims were allowed to lapse. In 1993, NDU Resources Ltd. optioned the remaining claims as a possible bulk tonnage gold target modelled on the Fort Knox deposit in Alaska. The program was conducted on both sides of the border and consisted of soil geochemical surveys, prospecting and two diamond-drill holes (234 metres) in Yukon. Soil sampling outlined large areas of moderately to strongly anomalous tungsten, molybdenum, bismuth, beryllium and gold values but rock analyses and drilling returned disappointing results. The option was allowed to expire without additional work being done. In 1998, Nordac Resources Ltd. (renamed Strategic Metals Ltd. in 2001) restaked the deposit and performed additional prospecting and limited rock sampling, which were directed primarily toward beryllium potential. Strategic conducted a digital data compilation and performed additional prospecting in 2001. In 2003, Strategic conducted a short program of prospecting and minor hand trenching which focussed on areas to the south and west of the deposit in Yukon where earlier soil geochemistry and prospecting had identified tungsten-molybdenum-beryllium mineralization associated with sheeted quartz veins and veinlets. This was followed up with a road building and excavator trenching program in the same area during the summer of 2004. In 2005, on behalf of Strategic Metals Ltd., a total of 24 rock samples and 21 core samples were taken. Ten of the rock samples and all the core originated in Yukon; the other 14 rock samples were collected in British Columbia. In 2008, Largo Resources Ltd. on behalf of Strategic Metals Ltd., conducted preliminary engineering studies in support of the completion of a scoping study/preliminary economic assessment, environmental baseline studies, tailings site assessment study, access road and aggregate quality investigation, and access road maintenance.