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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  20-Sep-2017 by Karl A. Flower (KAF)

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NMI
Name NO. 1, GIANT COPPER, 10 LEVEL PORTAL Mining Division New Westminster
BCGS Map 092H015
Status Prospect NTS Map 092H03E
Latitude 049º 10' 05'' UTM 10 (NAD 83)
Longitude 121º 00' 49'' Northing 5448037
Easting 644796
Commodities Silver, Lead, Zinc, Copper, Gold Deposit Types L04 : Porphyry Cu +/- Mo +/- Au
Tectonic Belt Intermontane Terrane Methow
Capsule Geology

The No. 1 (10 Level Portal) prospect is located in the head waters of Smitheram Creek, on the southeast side of Silverdaisy Mountain.

The area straddles the Hozameen fault. West of the fault, the property is underlain by mafic volcanics and lesser sedimentary rocks of the Permian-Jurassic Hozameen Complex. East of the fault, it is underlain by younger sedimentary rocks of the Lower and Middle Jurassic Ladner Group. Both packages have been intruded by many early-middle Tertiary plutons.

The prospect is hosted in steeply dipping and tightly folded rocks of the Ladner Group, consisting mainly of argillites and siltstones with minor greywacke and felsic tuff. Intruding this package is the Invermay stock, a medium-grained diorite to granodiorite body thought to be Oligocene. Numerous dikes and sills ranging from diorite to pyroxenite also intrude but pre-date the deformation and metamorphism.

Within the stock, deuteric alteration of the feldspars, hornblende and biotite is moderate to strong and accessory tourmaline is abundant. The argillites and siltstone have been strongly altered to pyritic biotite hornfels over an area several hundred metres wide surrounding the stock. The hornfels contain local concentrations of thin tourmaline veinlets containing minor pyrite and chalcopyrite.

The No. 1 occurrence is located in a breccia zone approximately 330 metres northeast of the AM deposit (MINFILE 092HSW001). It is very similar to the AM in terms of mineralization, host rocks and geochemical signature and is thought to represent a faulted segment of that deposit (Exploration in B.C. 1989, page 93). Both occurrences are located within a few hundred metres of the Invermay stock, within the contact metamorphic halo. The No. 1 and most of the smaller breccia zones on the Giant Copper property are interpreted as explosive diatreme breccias related to the intrusion of the stock.

In1989, a rotary drilling program on the western portion of the breccia intersected a higher grade structure, possibly a vein. Hole GCR-89-05 yielded 0.67 per cent copper, 2.68 per cent lead, 1.76 per cent zinc, and 247.54 grams per tonne silver over 27.4 metres; while hole GCR-89-20 intersected 9.0 metres yielding 0.99 per cent copper and 88.6 grams per tonne silver (Assessment Report 19878). This higher grade structure was reported to be open to the west. Trenching on the area yielded up to 1.4 per cent copper, 0.7 per cent lead, 0.07 per cent zinc, 3.10 grams per tonne gold and 315.4 grams per tonne silver (Assessment Report 19878).

The area has been explored as part of the Giant Copper (MINFILE 092HSW001) and Invermay (MINFILE 092HSW002) occurrences. These occurrences were discovered in the early 1930’s. The two properties were consolidated in 1956 by Canam Mining Corp. Between 1955 and 1963, several companies optioned the property and carried out exploration and development programs. After a two year option, Giant Mascot Mines Ltd. purchased all of Canam's assets in 1966. Giant Mascot Mines Ltd. continued work between 1966 and 1972. This included programs of ground magnetic and induced polarization surveys, geological mapping, rock and soil sampling and a lone diamond drill hole, totalling 38.4 metres, on the 10 Level, 26 Mile and Main Breccia grids. Further work ceased until 1979, when limited diamond drilling and rehabilitation work was carried out on the No. 10 level by G.M. Resources. By the end of 1980, 6017 metres of underground drifts and raises, and 14,078 metres of diamond drilling had been completed on the property. The property lay dormant again until 1988, when Bethlehem Resources Corp. acquired it from Campbell Resources Inc. (formerly Giant Mascot Mines Ltd.). Between 1988 and 1990, a comprehensive exploration and evaluation program was carried out; including extensive geochemical sampling, 9.5 line-kilometres of combined ground magnetic, electromagnetic and induced polarization surveys, rehabilitation of the 10 Level workings, trenching, re-logging of previous drill cores, 16 surface and underground diamond drill holes, totalling 1304.9 metres, and 35 rotary drill holes, totalling 2901.1 metres. In 1996, Imperial Metals completed a program of diamond drilling (16 holes, totalling 3457 metres) and 658.8 line-kilometres of airborne geophysical surveys on the area with the aim of establishing a second open-pit resource on the Giant Copper property (MINFILE 092HSW001). No further exploration work is reported until 2015, when a program of soil and rock sampling was completed. This work identified a northeast trending zone (200 by 350 metres) of weak copper-gold soil anomaly immediately south of the Giant fault and the 15 Level adit and approximately 1 kilometres north east of the No.1 breccia zone.

Bibliography
EMPR ASS RPT 18340, 19045, *19878, 23902, 24157, 24986, 36083
EMPR EXPL *1989-91-93
GSC BULL 238
GSC MAP 12-1969; 737A; 1069A; 41-1989
GSC P 69-47
EMPR PFD 800610, 831015

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