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File Created: 27-Jul-2016 by Nicole Barlow (NB)
Last Edit:  24-Jun-2020 by Karl A. Flower (KAF)

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NMI
Name BACKBURN SOUTH Mining Division Kamloops
BCGS Map 092I033
Status Showing NTS Map 092I06W
Latitude 050º 20' 46'' UTM 10 (NAD 83)
Longitude 121º 27' 59'' Northing 5578239
Easting 609116
Commodities Gold Deposit Types
Tectonic Belt Intermontane Terrane Quesnel
Capsule Geology

The Backburn South occurrence is located approximately 10.3 kilometres southwest of Spences Bridge, at an elevation of 1470 metres. The property can be accessed via the Botanie Lake Road, which is along Highway 12, approximately 1 kilometre northeast of its junction with the Trans-Canada Highway. An alternative access point may be gained via the Sleetis Creek Road, which is located approximately 9 kilometres from the start of Botanie Lake Road. The Sleetis Creek and Skoonka Forestry roads are linked via a 1.5 kilometre connecting road dubbed the “JJ Connector”, which was built in 2006 to allow easier access through the property and is where the JJ showing is situated.

Regionally, the northwest-southeast–trending Cretaceous Spences Bridge Group is part of the southern Intermontane tectonic belt of the Canadian Cordillera. The Spences Bridge Group volcanics are faulted against older plutonic and related metamorphic rocks of the Triassic-Jurassic Mount Lytton Complex. The dominant rock types within the area are subaerial andesite flows and tuffs, overlain by amygdule-rich basaltic flows. Minor felsic flows occur within these intermediate and mafic rocks, along with some sandstone, shale and conglomerate units. Stratigraphy is intruded by abundant Late Triassic and/or Jurassic to Miocene plutons. Metamorphic assemblages consist of Cache Creek Complex mélanges and Bridge River Complex metamorphic and ultramafic rocks. Quaternary sediments occur as thick drifts along the main rivers and some of the larger creeks. Major structural features in the region are steeply dipping normal faults, oriented subparallel to the western-bounding Fraser (River) fault system. The faults have two dominant trends: northwest-southeast and north-south (Assessment Report 34626). The Deadwood, Ember, Discovery and Backburn gold showings define a 3-kilometre long corridor of low-grade gold mineralization (Assessment Report 34636).

Locally, the Spences Bridge Group is overlain by Tertiary mafic to felsic volcanics of the Kamloops and Princeton groups, which are in turn cut by small intrusions of intermediate composition. The Spences Bridge Group underlying the Skoonka Creek property is further divided into two assemblages, the Pimainus Formation and the Spius Creek Formation. Above the basal conglomerate, the Pimainus Formation is a predominantly volcaniclastic package comprising subaerial andesite ash, crystal, and lapilli tuffs (Assessment Report 29084). These flows are poorly sorted, weakly to non-bedded, and may contain up to 50 percent amygdules. Sandstone, shale, and conglomerate units can also be found alongside the andesite flows within the Pimainus Formation. The Spius Creek Formation overlies the Pimainus Formation and comprises amygdule-rich basaltic flows. Bedding is often apparent in the fine-grained tuff units throughout the property, oriented at a northwesterly strike and dipping between 0 and 40 degrees to both the northeast and southwest (Assessment Report 28182).

Mineralization in this area consists of a mixture of andesite crystal and lapilli tuffs with centimetre-scale stockwork and discontinuous quartz veins. Silica alteration occurs as pervasive to localized zones associated with thin quartz veinlets or stockwork veining mineralization in the host rock (Assessment Report 29084). Weak limonite alteration also occurs along fracture planes and trace to minor, fine-grained, disseminated pyrite occurs in the wall rock adjacent to veining. The Backburn South anomaly contains an exposed stockwork quartz vein hosted in the Pimainus crystal tuff, near the contact with the lapilli tuffs. Moderate silica and clay alteration occurs in the host rock surrounding the vein. Trace to minor amounts of fine-grained disseminated to boxwork-textured pyrite occurs within altered tuffs. The samples contained open-space filling textures with local breccia zones of tuffisitic clasts and strong clay alteration; weak hematite staining occurs along fractures. Hematite alteration is present, but likely not related to hydrothermal processes. There are two styles of gold mineralization: (1) multi-stage massive, banded veins with associated breccia zones and intense proximal silica to distal argillic alteration and (2) narrow stockwork veinlets with disseminated pyrite and moderate silica, minor carbonate, limonite and clay alteration. The second style is more common in the Backburn showings (Assessment Report 34626).

Rock samples collected from brecciated vein material at Backburn South assayed up to 3.8 grams per tonne gold (Assessment Report 29084). The best sampling results from the Backburn South trench, over a range of 34 metres, consisted of 280 parts per billion gold over 8 metres in the northern half, near the contact between crystal and lapilli tuff (Assessment Report 29084). This sample was located on the eastern edge of a 300 metre area that contains three separate clusters of gold in soil anomalies that range from 43.5 to 1257.9 parts per billion gold in soil (Assessment Report 29084). Backburn South also had a soil sample (number 32375) that assayed 949.3 parts per billion gold (Assessment Report 29084).

In 2005, work completed by Strongbow Exploration Inc. in the Backburn area consisted of 294 samples taken at 50 metre station spacing and 50 metre line spacing to infill a portion of the 2005 regional soil survey. Five ground magnetic surveys were completed between April 2 and September 24 2006, contributing to a total of 33.7 line-kilometres. This sampling extended the regional grid 500 metres to the east and 300 metres to the south and identified two areas of interest: Backburn Central and Backburn South. Backburn Central and Backburn South were followed up with detailed prospecting and soil trenching later that year. Strongbow’s 2007 exploration program consisted of property and detailed mapping, grid and trench soil sampling (2262 samples), surface to trench rock sampling (783 samples), mechanized and hand trenching (432 metres), ground geophysics (33.9 line-kilometres of magnetometer surveying), airborne geophysics (580 line-kilometre DIGHEM V survey), diamond drilling (3147 metres in 13 holes; 1129 core samples assayed) and road construction (1.46 kilometres). The property-scale mapping (1:10 000) focused on the contact between the Spius Creek and Pimainus formations while detailed mapping (1:2 500) was conducted over the Backburn and Zebra showings. The airborne magnetic, electromagnetic and radiometric surveys covered the 2006 airborne survey area. The fall diamond drilling program tested the Deadwood (six holes), Ember (two holes), Backburn (four holes), and JJ (one hole) zones.

Bibliography
EMPR ASS RPT 27672, 28182, 28559, *29084, *34626
GSC MAP 42-1989
Chang, F. (2007-03-09): Technical Report 43-101F1 (Item 1) – The Skoonka Creek Project

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