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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  06-Jun-2014 by Nicole Barlow (NB)

Summary Help Help

NMI 092O3 Cu3
Name TASEKO (EMPRESS), EMPRESS, GRANITE CREEK Mining Division Clinton
BCGS Map 092O013
Status Developed Prospect NTS Map 092O03W
Latitude 051º 06' 16'' UTM 10 (NAD 83)
Longitude 123º 24' 00'' Northing 5661516
Easting 471995
Commodities Copper, Gold, Molybdenum, Silver, Corundum, Gemstones, Sapphire Deposit Types L04 : Porphyry Cu +/- Mo +/- Au
Q10 : Gem corundum hosted by alkalic rocks
Tectonic Belt Coast Crystalline Terrane Overlap Assemblage
Capsule Geology

The Empress copper-gold porphyry deposit is on the east side of Granite Creek, 800 metres above its confluence with the Taseko River. A major strike-slip fault, the Tchaikazan Fault is interpreted to underlie the Taseko River Valley to the north of the showing. The showing is in andesite, porphyry flows and bedded fragmental dacitic andesite of the Upper Cretaceous Powell Creek Formation adjacent to its contact with Late Cretaceous quartz diorite of the Jurassic to Tertiary Coast Plutonic Complex. The contact strikes to the west and dips moderately to the north. The volcanic hostrocks are bleached, pyrophyllite altered (-±sericite) and extremely silicic. Wallrock alteration of the volcanics roughly parallels the intrusive contact and comprises (from the contact upward) quartz-magnetite, quartz and pyrophyllite-andalusite -± quartz -± plagioclase.

Three zones of copper-gold mineralization have been defined: the Lower North, Upper North and 76 zones. The latter two zones appear to be fault controlled, whereas the Lower North zone appears to be related to the intrusive contact. The Lower North zone has the strongest mineralization. Preliminary calculations indicate that over 5 million tonnes of greater than 1 per cent copper (plus gold) occur in a relatively flat-lying, disc-shaped pod. The pod is situated approximately 140 metres below surface and is open to the northwest, northeast and southwest. The Upper North zone is less well defined and consists of spotty mineralization occurring in a northeast linear trend from near surface to approximately 120 metres depth. The 76 zone appears to be vertical and trends in a northeast direction. The zone is open to the northeast but appears to be cut off by the quartz diorite stock at depth.

Pyrite, chalcopyrite and magnetite are the most abundant metallic minerals and are present as disseminations throughout the altered volcanic rocks, with minor amounts in fractures and as veinlets. Molybdenite and pyrrhotite are present in small amounts. Microscopic examinations of gravity concentrates of mineralized core indicate the additional presence of trace galena, sphalerite and free gold.

In the Empress deposit area, corundum, in association with andalusite pyrophyllite rock, is reported in several drillholes. It might be a geochemical pathfinder.

The Empress deposit was discovered in 1935. Since that time, the Taseko region has been explored intermittently through mapping, prospecting, and geochemical and geophysical surveying by various companies. Exploration companies have generally held the Empress, Rowbottom (092O 029) and Buzzer (092O 038) showings concurrently; soil sampling and step-out drilling frequently occur in the regions between the showings. Historical drill programs on the property have identified porphyry copper-molybdenum deposits at the Empress and have partially defined the Granite Creek and East zones through drilling and soil sampling, as follows (adapted from Assessment Report 32841):

Hole # Company Year

DDH 1-5 Phelps Dodge 1964 -1965

A 4–7, X 1-4, 8 Scurry Rainbow 1969

S 1-64 Sumitomo 1970

76 1–8, Q 1-39 Quintana 1976

T88 1-7 Alpine-Westley 1988

W89 1-16 Westpine 1989

W90 17-35 Westpine-ASARCO 1990

W91 36-55 Westpine-ASARCO 1991

07 58-63 Great Quest Metals 2007

08 64-73 Great Quest Metals 2008

GC11 74-79 Great Quest Metals 2011

Based on drilling results from 1990 and earlier, a reserve estimate of 6 760 500 tonnes of 0.73 per cent copper, 0.82 gram per tonne gold and 1.71 grams per tonne silver within the Lower North zone was announced in 1991 (Northern Miner, February 18, 1991). A March 1991 "preliminary pre-feasibility" study of the Empress deposit has calculated 10 048 000 tonnes of 0.61 per cent copper and 0.79 gram per tonne gold at a 0.4 per cent copper cut-off grade (George Cross News Letter No. 151, August 7, 1991).

In 1991 drilling, two potential new zones were discovered: the East and Granite Creek zones. In the Granite Creek zone, situated 243 metres north of the Empress, a drillhole intersected 88 metres grading 0.23 per cent copper and 0.27 gram per tonne gold (George Cross News Letter No. 7, 1992).

In 1995, with Explore BC Program support, Westpine Metals Ltd. conducted a program of rock and soil sampling and 14.2 line kilometres of induced polarization surveying on the Rowbottom and Buzzer zones. Three areas of elevated metal values were defined on the Rowbottom grid (Explore BC Program 95/96 - M114).

In 1996 and 1997, the property was sampled for sapphires; the largest found was 20 by 3 millimetres (George Cross News Letter No. 155, August 13, 1997). In nine collected samples, sapphires were identified but not of gem quality. No further work was recommended for sapphires (Assessment Report 26037).

Westpine Metals Ltd. changed its name to Great Quest Metals Ltd. in 1998. No work was completed on the property between 1999 and 2007.

In 2007, a program of step-out drilling from Granite Creek zone was conducted to test the Granite Creek magnetic anomaly and improve the Empress resource estimate. Follow-up drilling was completed in 2008.

Granite Creek Gold Ltd. acquired a 51 per cent interest in the property in 2010. A short program of prospecting and rock and soil sampling was completed in the Empress and Buzzer West areas. The program focused on previously identified outcrop and trenched areas. Subsequent drilling in 2011 focused on the Buzzer zone, whereas rock sampling focused on the Rowbottom showing.

Bibliography
EM INF CIRC 1998-1, p. 24
EMPR AR *1935-F24; 1956-35; 1968-155; 1969-181
EMPR ASS RPT 2134, 2226A, 2226B, 2874, 5764, 6085, 17871, *19350
*20889, 21985, 23361, 24088, 24753, 25262, 25759, 26037, 29557,
30169, 32064, 33392
EMPR Explore B.C. Program 95/96 - M114
EMPR FIELDWORK *1976, pp. 47-53; 1986, pp. 157-169; 1988, pp.
153-158; 1991, p. 232; 1997, pp. 26-1-26-14
EMPR GEM 1975-E119; 1976-E132
EMPR GEOLOGY *1976, 67-84
EMPR OF 1987-3; 1992-1; 1998-8-F, pp. 1-60; 1998-10
EMPR PF (Montgomery, J.H. (1968): Report on the Taseko Mohawk,
Empress, Granite Creek and Spokane Prospects Near Taseko Lakes;
*Lambert, Ellen, (1989): Geology, Geochemistry and Mineralization
of the Taseko Property; News Release, Westpine Metals Ltd., Jan.
1991; Taseko Mines Limited Annual Report 1997 (17 pages); Press Release: Excellent Results Received from Prosperity Pilot Plant Program, November 17, 1997; Press Release: Major Milestone Reached for Prosperity, March 16, 1998; Press Release: Prosperity Project Achieves Major Environmental Review Milestone, April 29, 1998; Press Release: Prosperity Scheduled to become Largest Gold Mine in Canada, June 10, 1998; Press Release: Taseko Mines and British Columbia Government Sign Cooperative Resource Development Protocol, December 15, 1998; Press Release: Taseko to Acquire $6 Million of Exploration Work, January 15, 1999; Press Release: Giant Gold-Copper Deposit Advancing Towards Production Decision, January 21, 1999; Mining Quarterly, Vol 6, No 1, Winter 1999; Company booklet: Prosperity Gold-Copper Project: Responsible Mineral Development)
EMR MIN BULL MR 223 B.C. 189
GSC OF 534; 2207
CIM Spec. Vol. *46, pp. 441-450
GCNL #35(Feb.20),#154(Aug.11),#171(Sept.6),#181(Sept.20),#192(Oct.5),
#198(Oct.16),#219(Nov.15), 1989; #101(May 25),#121(Jun.22),
#138(Jul.18),#143(Jul.25),#147(Jul.31),#155(Aug.13),#163(Aug.23),
#175(Sept.11),#190(Oct.1), 1990; #97(May 21),#117(June 18),
#131(Jul.9),#139(Jul.19),#142,#151(Aug.7),#158(Aug.16),
#172(Sept.6),#179(Sept.17),#185(Sept.25),#191(Oct.3),#18(Jan.25),
#24(Feb.4),#51(Mar.13),#60(Mar.26),#68(Apr.9), 1991; #7(Jan.10),
#41(Feb.27), 1992; #155 (Aug.13), 1997
N MINER Aug.6,27, 1990; Feb.18, Mar.25, Apr.8, Sept.2,24, 1991
NW PROSP Sept./Oct. 1989
Placer Dome File

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