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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  27-Nov-14 by Laura deGroot(LDG)

Summary Help Help

NMI 104O13 W1, Be1
Name NORTHERN DANCER, LOGTUNG, LOG JAM CREEK, B.C. ZONE, JAM 2 Mining Division Atlin
BCGS Map 104O092
Status Developed Prospect NTS Map 104O13E
Latitude 59º 59' 44" N UTM 09 (NAD 83)
Longitude 131º 36' 06" W Northing 6653770
Easting 354891
Commodities Tungsten, Molybdenum, Bismuth, Copper Deposit Types L07 : Porphyry W
K07 : Mo skarn
Tectonic Belt Omineca Terrane Dorsey, Plutonic Rocks
Capsule Geology

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:
(http://www.largoresources.com)
--------------------------------------------------------
Category Amount (tonnes) WO3 (%) Mo (%)
Measured 30,800,000 0.114 0.030
Indicated 192,600,000 0.100 0.029
Inferred 201,200,000 0.089 0.024
--------------------------------------------------------


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.

Bibliography
EMPR ASS RPT *6491, *12715, 23305, 25933, 28112, 30776
EMPR EXPL 1977-E243; 1978-E275,E276; 1999-19-31
EMPR FIELDWORK 1977, p. 70; *1978, pp. 47-50; 2001, pp. 35-40
EMPR GEOLOGY 1977-1981, pp. 186-187
EMPR MAP 65 (1989)
EMPR OF 1992-1; 1996-11; 1998-8-F, pp. 1-60; 2000-6
EMPR PF (2nd Annual Report: Logtung Resources Ltd., 1979; *Noble, S.R. et al. (1984): The Logtung large tonnage, lowgrade W (scheelite) - Mo porphyry deposit, South-Central Yukon Territory; EG V. 79, pp. 848-868; Prospectors Report 2000-28 by Dan Blower)
GSC EC GEOL 23, p. 24
GSC MAP 18-1968
GSC OF 561; 2779
GSC P 68-55; *78-1A, pp. 287-292
GCNL #120,#132,#179, 1978; #4,#46,#163,#219,#248, 1979; #116, 1980; #36, 1981
N MINER Apr.6, Sept.14, 1978; Mar.22, 1979; Jul.10, Aug.7, 1980; PR Mar.12, 2009
W MINER Nov. 1981; May 1982
Abbott, J.G. (1981a): Geology of Seagull tin district, Yukon Geology and Exploration 1979-1980, DIAND, pp. 32-44
*Abbott, J.G. (1981b): Logjam, Yukon Geology and Exploration, 1979-1980, DIAND, pp. 147,148
*Noble, S.R. (1982): Petrology and fluid inclusion study of W-Mo mineralization at the Logtung deposit, south-central Yukon Territory; unpublished M. Sc. Thesis, Univ. Toronto, p. 286
*Poole, W.H. (1956): Geology of the Cassiar Mountains in the vicinity of the Yukon-B.C. boundary, unpub. Ph.D. Thesis, Princeton Univ.
*Stewart, J.P. (1983): Petrology and geochemistry of the intrusives spatially associated with the Logtung W-Mo prospect, south-central Yukon Territory, unpub. M. Sc. Thesis, Univ. Toronto, p. 243

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