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File Created: 24-Jul-1985 by BC Geological Survey (BCGS)
Last Edit:  27-Mar-2022 by Nicole Barlow (NB)

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NMI 104B1 Au2
Name S1, S-1, UNION, BIG MISSOURI, PREMIER, DILWORTH Mining Division Skeena
BCGS Map 104B020
Status Developed Prospect NTS Map 104B01E
Latitude 056º 06' 58'' UTM 09 (NAD 83)
Longitude 130º 01' 15'' Northing 6219484
Easting 436519
Commodities Gold, Silver, Zinc, Lead, Copper Deposit Types G07 : Subaqueous hot spring Ag-Au
I02 : Intrusion-related Au pyrrhotite veins
G06 : Noranda/Kuroko massive sulphide Cu-Pb-Zn
Tectonic Belt Intermontane Terrane Stikine
Capsule Geology

The S1 Zone, which is located 400 metres northeast of the Big Missouri deposit, lies within south-southeast striking, moderately dipping andesite, agglomerate and lapilli tuff, with interbedded cherty tuff of the Lower Jurassic Unuk River Formation. (See Big Missouri (104B 046) for enhanced geology).

The S1 Zone lies immediately west of the north trending Union Creek Fault and occurs within the Middle Horizon, which is the same horizon containing the Big Missouri deposit. Three distinct southwest dipping cherty tuff beds, approximately 20 metres apart, comprise the Middle Horizon. These are separated by plagioclase-amphibole porphyritic andesite units, which show weak sericite and silica alteration.

The cherty tuff beds are generally 1 to 2 metres thick and contain carbonate, andesite fragments, laminated and/or mineralized chert fragments and sulphide mineralization. A well-developed footwall breccia grades upward into each cherty tuff bed and downward into a stringer zone.

The andesite sequence, which encloses the cherty tuff and breccia strikes southeast and dips 20 to 30 degrees southwest. This sequence is likely gently warped around a northeast trending axis. Several steep dipping, north-northwest and northeast trending faults juxtapose the strata.

Mineralization, consisting of pyrite, sphalerite, galena, and chalcopyrite, occurs as disseminations, lenses, pods, and stringers within the cherty tuff, footwall breccia, and footwall and hangingwall stringer zones. Weakly laminated, semi-massive to massive sulphide occurs locally at the base of the cherty tuff beds. The lower cherty tuff-footwall breccia zone has the greatest sulphide content.

Gold and silver occur only as electrum which is strongly associated with sphalerite. Electrum also occurs within galena and along sulphide grain boundaries. All the sulphides are closely associated, and commonly intergrown in polycrystalline aggregates along veinlets.

Production from the S-1 zone in 1990 totalled 304,000 tonnes of ore grading 2.4 grams per tonne gold and 10.0 grams per tonne silver. Geological (inferred) reserves in 1991 were 800,000 tonnes grading 2.2 grams per tonne gold and 10.0 grams per tonne silver (D. Alldrick, PhD Thesis, UBC, 1991).

Work History

Ascot Resources Ltd conducted exploration on the Dilworth Property in 2007 and 2008 and subsequently acquired the Premier Gold Property from Boliden Ltd under the terms of a 2009 option agreement.

In 2009, Ascot Resources drilled three drill holes (drillholes P09-021 to P09-023) on the S1 Pit. Most of the rock encountered in drill core was poorly altered andesite, with rare Feldspar Porphyry. While there were occasional results of less than 0.50 gram per tonne gold, generally most assay results were low (Assessment Report 31489).

In 2010 Ascot Resources drilled three drill holes on individual pads on the S1/Creek Zone, all oriented to the east. Two holes, P10-074 and 076 were drilled with a small drill below the S1 Pit from corners on the main haul. The other hole, P10-114 was drilled by an NQ diamond-drill. It was located above and to the north of the S1 Pit. P10-114, contained several short intersections of Premier Porphyry in the middle of the hole, plus a mineralized zone of 0.31 grams per tonne gold over 123.14 metres near the top of the hole including several short sections of siliceous breccia (Assessment Report 32357). Several faults were encountered after 120 metres that may correspond to the Cascade Creek Fault that also cut off mineralization. Mineralization at the bottom of the hole is poor. The upper mineralized zone, including several short intervals greater than 2 grams per tonne gold (Assessment Report 32357), are potentially within the boundary of any expansion on the S1 Pit. This is also part of the trend of mineralization from Unicorn (104B 044) and could be considered the southern extension of this zone yielding a strike length of over 900 metres.

In 2011, several pad sites were established around the S1 Pit to test for mineralization extending to the north and south. There was also some overlap with drilling from the Province/Big Missouri Zones which show the Big Missouri mineralized zone extending into the bottom of the S1 Pit. The mapped trace of the Jain Fault, that affects mineralization in the Province and Big Missouri areas, runs through the southern area of S1 and along the east side of the S1 Pit. There are no markers on the fault to determine offset or sense of displacement, and the Jain Fault truncates mineralization in this area. Typical drill results include P11-252, 0.42 gram per tonne gold and 3.3 gram per tonne silver over 56.0 metres which includes 0.85 gram per tonne gold and 4.6 gram per tonne silver over 9.53 metres and hosted in siliceous breccia (Assessment Report 33267).

See Big Missouri (104B 046) for related and specific historical work and bibliography. See also Yellowstone (104B 039) and Premier (104B 054) for details of the combined Dilworth and Premier properties that include the S1 and Big Missouri. See Big Missouri for Indicated and Inferred Resources of the Big Missouri, Mary Ellen (104B 092) and Dilworth (104B 039) deposits.

EMPR AR 1914-154; 1919-369; 1930-114
EMPR ASS RPT 2320, 3013, 6080, *6361, 21993, 29918, 31000, *31489, *32357, *33267, 35410
EMPR BULL 58; 63; 85
EMPR EXPL 1976-179
EMPR FIELDWORK 1980, pp. 201-209; 1982, pp. 182-195; 1983, pp. 149-164; 1984, pp. 316-341; 1985, pp. 217,218; 1986, pp. 81-102
EMPR OF 1987-22; 1998-10
EMPR PF (CORP Profile, Tournigan Mining Explorations Ltd., National Securities Corporation, in Big Missouri - 104B 049)
GSC MAP 9-1957; 1829; 307A; 1418A
GSC MEM 132; 175
GSC P 89-1E, pp. 145-154
CIM SPEC. Vol. *37, pp. 202-215
GAC Dykes et al: Field Trip "C" Guidebook, Oct.19-21, 1988 (in Property File 104B046)
GCNL #72, 1982; #228,#288, 1986; #45,#207,#245, 1987; #102, 1988
N MINER May 12, 1983; Dec.1, 1986; Nov.16, 1987; June 6, 1988
W MINER May, 1983
Alldrick, D.J. (1991): Geology and Ore Deposits of the Stewart Mining Camp, B.C.; PhD Thesis, UBC
Brown, D. (1987): Geological Setting of the Volcanic Hosted Silbak Premier Mine, M.Sc. Thesis, University of British Columbia (copy in Property File - 104B 054)
Galley, A. (1981): Volcanic Stratigraphy and Gold-Silver Occurrences on the Big Missouri Claim Group, Stewart, British Columbia, M.Sc. Thesis, University of Western Ontario
Stockwatch Oct.19, 1987
Westmin Resources Limited, Annual Report, 1983
Christopher, P.A. (2009-08-03): Technical Report on the Premier Gold Project
Kirkham, G. (2012-06-18): Technical Report on the Resource Estimate for the Premier Gold Property
Kirkham, G. (2012-08-20): Revised Technical Report on the Resource Estimate for the Premier Gold Property
Puritch, E. (2013-03-27): Technical Report and Resource Estimate for the Big Missouri and Martha Ellen Deposits, Premier Gold Property
Rennie, D.W. (2018-06-22): Technical Report on the Premier-Dilworth Project
Rennie, D.W. (2019-01-17): Technical Report on the Premier Project
Bird, S.C., Meintjes, T. (2020-02-28): Resource Estimate Update for the Premier Gold Project, Stewart, British Columbia, Canada
Ascot Resources Limited (2020-05-22): Premier & Red Mountain Gold Project Feasibility Study NI 43-101 Technical Report, British Columbia