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File Created: 08-Apr-2009 by George Owsiacki (GO)
Last Edit:  29-Jan-2014 by Nicole Barlow (NB)

Summary Help Help

NMI
Name LOST SWEDE Mining Division Cariboo
BCGS Map 093A091
Status Showing NTS Map 093A13W, 093B16E
Latitude 052º 55' 02'' UTM 10 (NAD 83)
Longitude 121º 58' 33'' Northing 5863564
Easting 568869
Commodities Gold Deposit Types C02 : Buried-channel placers
Tectonic Belt Intermontane Terrane Quesnel, Overlap Assemblage
Capsule Geology

The Lost Swede placer showing is situated along the east side of the Swift River, near the confluence with Victoria Creek. The northern property boundary can be accessed by driving 3 kilometres south along the 1300 Road, 7 kilometres west then south along the 13A Road and 2 kilometres south along the 13A Branch 10 Road. The 1300 Road is situated 33 kilometres east along the Barkerville Highway (Highway 26) from Highway 97 in Quesnel. The Branch 10 Road provides access for an additional 10 kilometres to the southernmost portion of the property. Several recently constructed branch roads provide two- and four-wheel-drive access to most parts of the property.

The area is underlain by Upper Triassic to Lower Jurassic black slate and volcanogenic greenstone. Volcaniclastic sequences in the area are dominated by mafic rocks, mainly basalt and andesite agglomerate and tuff. The Eureka thrust fault lies approximately 12 kilometres east of the showing and defines the tectonic boundary between the Quesnel and Barkerville terranes.

Bedrock geology of the Lost Swede property comprises Middle to Upper Triassic Nicola Group siltstone, quartzite, mudstone and sandstone. Thick sequences of postglacial alluvium and glacial sediments blanket the central portion of the Swift River Valley, where bedrock exposures are rare. Scattered siltstone and quartzite outcrops occur at lower elevations proximal to the Swift River.

The Lost Swede property covers a large, 1 to 2-kilometre-wide area that extends 7.5 kilometres along the east side of the Swift River Valley, near the confluence of Victoria Creek. The surficial geology was examined across this area from June to October 2007 to identify potential locations for two types of gold-bearing placer targets. The first target consisted of postglacial outwash gravels where the best gold concentrations occur in coarse-grained boulder-rich lag horizons. The boulder horizons are usually buried beneath varying thicknesses of finer grained alluvial sediments and are underlain by glacial sediments or bedrock. Basal lag exposures are rare across the property and are limited to areas proximal to the Swift River along cut banks and in areas along roadcuts. The second target was made up of older gravels (preglacial and/or interglacial) that are normally confined to buried paleochannels and are usually well masked beneath widespread glacial sediment layers of unknown thicknesses. No older gravel exposures were identified on the property, although important bedrock exposures studied along the Swift River at the southeast end of the property give strong evidence for the potential location of a northwest-trending buried paleochannel.

Results of the 2009 seismic refraction survey indicated that the terrace at the valley bottom is composed of sediment sequences with a maximum thickness of greater than 45.7 metres. At the side-valley terrace, the average bedrock depth was 24.4 metres; the subsurface slopes gently to the north and west, roughly following the shape of the terrace surface.

Very little written record exists for placer mining in the area; however, previously disturbed areas provide evidence of past activities. Between 1874 and 1945, the total recorded placer gold production for the Swift River was 86 001 grams (2765 ounces) of gold (Assessment Report 31575, page 13).

A total of 20 auger drill holes with depths ranging from 2.7 to 35.9 metres were drilled along the east side of the Swift River Valley during October and November 2007. Older gravels were identified at a higher elevation in drillhole ADH 18, along a gently sloping valley-side terrace measuring up to 200 metres wide. This was the only hole where an older gravel unit was drilled to bedrock (13.7 metres). The basalmost 1-metre interval sampled from the 1.8-metre-thick older gravel layer yielded a high-grade gold concentration equivalent to 5.9 grams per tonne (or grams per cubic yard). This result in the older gravels overlying bedrock illustrates the potential for similar grades in other untested paleochannel bedrock locations (Assessment Report 29967).

In 2009, a seismic refraction survey was carried out on the property. The survey consisted of six lines totalling 2.52 kilometres. Later that year, eight hollow-stem auger drill holes totalling 162 metres were completed—five along the side of the valley and three along the terrace at the bottom of the valley.

In 2011, eight hollow-stem auger drill holes totalling 155.45 metres were completed in the northeastern corner of the Lost Swede property. In total, 61 core samples were collected and analyzed for gold content.

Drillhole LS09-1, drilled along the side of the valley, yielded 7-metre sections of gold-bearing interglacial gravels. Gold grades across the 7-metre sections ranged from 0.31 to 1.35 grams per tonne (Assessment Report 31575, page 2). A 3.4-metre sample of fractured bedrock recovered from the same drillhole returned 0.49 gram per tonne gold (Assessment Report 31575, page 2).

From the 2011 auger drill program, hole LS-11-01 yielded two 1.52-metre (5-foot) samples returning 2.6 and 1.4 grams per tonne gold (Assessment Report 33725, Appendix A, page 1) and hole LS-11-02 yielded three 1.52-metre samples returning 1.1, 1 and 1.2 grams per tonne gold (Assessment Report 33725, Appendix A, page 2).

Bibliography
EMPR ASS RPT *29967, 31033, *31575, *33725
EMPR BULL 97
EMPR OF 1987-9; 1989-14, 20; 1990-31
EMPR P 1990-3
GSC MAP 12-1959; 1424A; 1538G
GSC OF 574; 844

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