The Shamrock (Nellie 8) occurrence outcrops along the steep west bank of the Summers Creek valley, approximately 2 kilometres south-southwest of the south end of Missezula Lake.
The area is underlain by massive to crudely bedded lahar deposits and volcanic conglomerate of the Upper Triassic Nicola Group (Eastern Belt, Bulletin 69). The beds strike north and dip 40 to 60 degrees west. Previous mapping has also described the lahars as being andesitic flow breccias.
The volcanics are cut by a zone of narrow shears and fractures striking 020 to 025 degrees and dipping 70 degrees northwest. The zone trends 015 degrees for 37 metres and is 3 to 6 metres wide over most of its length. The shears are displaced by two post mineral faults striking 075 and 150 degrees and dipping 80 to 90 degrees north and 80 degrees northeast respectively.
Mineralization consists of massive veinlets and disseminations of chalcocite and a few grains of chalcopyrite and pyrite developed along the shears and fractures. Native copper is also reported. The sulphides are accompanied by malachite and azurite. A bulldozer trench (circa 1971), located approximately 135 metres southwest of the original mineralized zone, is reported to have exposed minor disseminated chalcocite in tuffaceous fragmental over a distance of 60 metres.
A trench, located approximately 140 metres southwest of the shear zone, exposes minor disseminated chalcocite over a length of 60 metres. This mineralization may be related to a diorite dike.
Other northeast- and northwest-striking shears mineralized with chalcopyrite, chalcocite and pyrite occur north and south of the main zone of shearing over a distance of 600 metres. The shears appear to be confined to the same stratigraphic horizon.
In 1969, sampling of trenches is reported to have yielded an average of 1.42 per cent copper over a width of 5.1 metres and a length of 30 metres (Property File – 8537).
In 1972, three chip samples, taken across widths of 4.3 to 4.9 metres and evenly spaced over a strike length of 17 metres from the main shear zone, averaged 2.40 per cent copper, 4.8 grams per tonne silver and 0.10 gram per tonne gold, whereas a series of grab samples, taken over 60 metres, from the southwestern trenched area yielded 0.23 per cent copper (Assessment Report 3955).
In 1985, three samples (2151R, 2299 and 3000) from an area of trenches yielded values from 3.388 to 7.495 per cent copper, 0.006 to 0.019 per cent molybdenum and 1.4 to 52.4 grams per tonne silver (Assessment Report 14141).
In 2017, two samples (Aspen-2 and -3) from the Shear zone and Extension adits yielded 6.43 and 3.18 per cent copper with 8.4 and 4.9 grams per tonne silver, respectively (Assessment Report 37347).
Work History
This showing was first explored in 1929, with the excavation of several trenches and a short adit. A small shipment of ore mined that year averaged 5.78 per cent copper (Minister of Mines Annual Report 1929, page 278).
In 1963, Consolidated Woodgreen Mines Ltd. conducted additional trenching and drilled at least three holes. Between 1969 and 1972, various geological, geophysical and geochemical surveys were completed over the showing by Delkirk Mining Ltd., Belcarra Explorations Ltd. and Rio Tinto Canadian Exploration Ltd.
In 1971 and 1972, Belcarra Explorations Ltd. completed programs of geological mapping, trenching and soil sampling on the area as the Nellie and Warm claims. Later that year, a 12.3 line-kilometre induced polarization survey and a 48.8 line-kilometre ground magnetic survey were completed on the claims.
In 1985, Vanco Explorations Ltd. completed a program of geological mapping and geochemical (rock and soil) sampling on the area as the Bloo, Climax and Thor claims.
In 2017 and 2018, Christopher Delorme completed minor programs of prospecting and rock sampling on the area as the SDJV property.
