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File Created: 03-Dec-1991 by George Owsiacki (GO)
Last Edit:  04-Apr-2022 by Karl A. Flower (KAF)

Summary Help Help

NMI
Name SIB (LULU), SIB, LULU, MARGUERITE Mining Division Skeena
BCGS Map 104B058
Status Prospect NTS Map 104B09W
Latitude 056º 35' 46'' UTM 09 (NAD 83)
Longitude 130º 30' 21'' Northing 6273441
Easting 407537
Commodities Gold, Silver, Antimony, Zinc Deposit Types G07 : Subaqueous hot spring Ag-Au
G06 : Noranda/Kuroko massive sulphide Cu-Pb-Zn
I05 : Polymetallic veins Ag-Pb-Zn+/-Au
I09 : Stibnite veins and disseminations
Tectonic Belt Intermontane Terrane Stikine
Capsule Geology

The Lulu zone of the SIB prospect is situated 2.5 kilometres west of the Unuk River and approximately 3 kilometres south-southeast of Tom Mackay Lake, 80 kilometres northwest of Stewart, B.C. and 46 kilometres southwest of Bell 2 Lodge on Highway 37.

At the Lulu showing of the Sib property, Eskay-type, gold-silver rich massive sulphide mineralization is situated in a succession of Eskay Rift rhyolite and mudstone that is directly correlative with the Eskay Creek deposit.

Bedrock in the Unuk map area consists of a thick (more than 5000 metres) succession of Upper Triassic to Middle Jurassic volcano-sedimentary arc-complex lithologies (Stuhini and Hazelton groups) underlain by Permian and older arc and shelf sequences (Stikine Assemblage) and overlain by Middle and Upper Jurassic marine-basin sediments (Bowser Lake Group). Rocks have been folded, faulted and weakly metamorphosed, mainly during Cretaceous time. Dioritic to granitic rocks that crop out east and west of the Prout Plateau represent at least four intrusive episodes spanning Triassic to Tertiary time. Remnants of Pleistocene to Recent basaltic eruptions are preserved locally (Exploration in British Columbia 1989).

The Sib property is situated on the west limb of a 9-kilometre long, 3-kilometre-wide north-northeast trending anticline comprised of Lower Jurassic Betty Creek and Mount Dilworth formations (Hazelton Group) volcano-sedimentary lithologies. These are overlain by and/or are in fault contact with synclinally folded Lower-Middle Jurassic Salmon River Formation (Hazelton Group) and Jurassic-Lower Cretaceous Bowser Lake Group sediments. The Betty Creek and Mount Dilworth formations stratigraphy is continuous along the length of both the Sib property and the adjoining Eskay Creek property (104B 008) to the north-northeast. The 21 zone deposits of Eskay Creek are approximately 4 kilometres along strike to the northeast of the Sib property boundary and are hosted by carbonaceous mudstones and rhyolite-mudstone breccias that are correlated with the unnamed lower member of the Salmon River Formation (see Eskay Creek).

Along the eastern side of the Sib property, Betty Creek Formation lithologies predominate. These include a 396- to 1828-metre-thick section of tan weathering, pale green andesitic plagioclase porphyritic lapilli tuff and agglomerate containing lesser amounts of interbedded crystal tuff and black mudstone. A mudstone unit comprises sedimentary-epiclastic rocks interbedded with minor tuffaceous and volcanic fragmental rocks. The unit is from 48 to 914 metres thick and includes interbedded mudstone, sandstone, conglomerate and ash and crystal tuff. An andesitic conglomerate unit occurs as a 487-metre long and up to 91-metre-wide lens.

Mount Dilworth Formation rocks occur along the western half of the property. A felsic volcanic unit, ranging in width from 121 metres to greater than 396 metres, comprises massive, banded and brecciated grey to white cherty felsic rock and includes several interbeds of mudstone-looking rock. Black, variably siliceous, carbonaceous mudstone up to 20 metres thick occur as interbeds in the felsic rocks. The Lulu zone mineralization occurs in this mudstone. A mudstone approximately 149 metres lower in the stratigraphic section than the "Lulu mudstone" hosts the Marguerite zone mineralization.

Overlying the Mount Dilworth lithologies are Salmon River Formation interbedded black cherts, carbonaceous mudstone and siltstone, and banded greywacke and siltstone.

Granodiorite dykes/sills are subparallel to stratigraphy within Mount Dilworth felsic rocks and occur in the northwest end of the property. The dikes or sills are up to 24 metres thick and 304 metres long and comprise grey to grey-green aphanitic to augite- feldspar porphyritic granodiorite.

Bowser Lake Group sediments comprised of moderate northwest dipping siltstone, sandstone and conglomerate occur in the extreme northwest corner of the property and are in fault contact with underlying Salmon River Formation rocks.

In general, the rocks on the Sib property form a simple homoclinal sequence trending approximately 035 degrees and dipping 20 to 80 degrees northwest.

Two distinct parallel zones of alteration occur concordant with stratigraphy at Sib. The eastern zone (or Central Anomalous zone) includes a 9-kilometre-long linear trend of conspicuous gossans situated along the western margin of the Betty Creek Formation volcanics and extends north to the Eskay Creek property. This trend encompasses the North, Battleship Knoll, Adit, 1100, South and Meadow zones at Sib. Alteration along this zone comprises intensely potassium metasomatized, brecciated, quartz flooded, pyritized andesitic tuffs with intermittent zones of discontinuous quartz-potassium feldspar-sulphide veins, vein breccias and stockworks. In 1990, all but one of twenty drill holes testing the eastern zone intersected stockworks carrying gold concentrations in the range of 0.34 to 4.29 grams per tonne over widths of up to 19 metres.

The western zone of alteration occurs west of the eastern zone within the felsic rocks of the Mount Dilworth Formation. The alteration comprises extensive and locally intense pervasive silicification and sodium metasomatism. Albitites have also been extensively developed. Drill holes targeted at mudstone interbedded in the felsic assemblage intersected gold and silver mineralization over wide intervals. Below an extensive interval of silicified and albitized felsic strata, drill hole 90-30 intersected 21 metres of black siliceous carbonaceous mudstone (Lulu mudstone). A 14-metre interval of the mudstone is mineralized with disseminated pyrite, framboidal pyrite, laminar pyrite and disseminated and fracture- controlled stibnite and sphalerite. Native gold, pyrargyrite and arsenopyrite occur in trace amounts. Gold and silver assayed 14.4 grams per tonne and 1059.5 grams per tonne respectively, across 14 metres (Summary Report in Statement of Material Facts #42-91). A short interval of the felsic hanging wall is sericitic. In the immediate footwall of the Lulu mudstone, felsic strata are highly pyritic and sericitic. The Lulu mineralization is underlain, 149 metres lower in the stratigraphic section, by the mineralized "Marguerite mudstone", which is the lowermost mudstone interbedded within the Mount Dilworth Formation felsic volcanics. A drill core assay across 4.5 metre assayed 3.5 grams per tonne gold and 36.3 grams per tonne silver (Summary Report in Statement of Material Facts #42-91).

Heritage Explorations Ltd. drilled 3 core holes in the Lulu Zone during 2002 and intersected 11.7 metres grading 19.5 grams per tonne gold and 1,602.9 grams per tonne silver in drillhole 2-113.

In 2008, Kenrich-Eskay Mining Corp's drillhole EK08-133 was a Lulu Zone confirmation hole and tested the immediate along strike extension of the zone. The hole is collared in an Eskay-type tholeiitic rhyolite flow breccia that passes into a 15.5 metre interval of highly faulted carbonaceous and finely pyritic mudstone. A 10-metre core interval from 55.7 to 65.7 metres depth returned grades of 9.0 grams per tonne gold, 405 grams per tonne silver, 0.2 per cent zinc, 0.3 per cent arsenic and 2.9 per cent antimony (Assessment Report 30726). This includes a 2.3 metre drilled interval (55.7-58.0 metres) of finely laminated to clastic pale to dark grey massive and semi-massive sulphides (likely stibnite)/sulphosalts and mudstone. This higher-grade interval returned 15.9 grams per tonne gold, 1299 grams per tonne silver, 0.5 per cent zinc, 0.4 per cent arsenic and 7.8 per cent antimony (Assessment Report 30726).

The most significant mineralization was obtained from hole EK08-134. That hole passed through the Coulter Creek Thrust Fault (CCTF) at 458 metres depth. The interval between 488.2 and 513.6 metres is a pale grey-green Eskay-type tholeiitic rhyolite intrusive into mudstone, and in part flow banded. Notably, thin, anastomosing quartz-polymetallic sulphide veins cut this unit. These locally carry up to 15 per cent sphalerite-galena-chalcopyrite-pyrite. Additionally, there are thicker, laminated “stockwork” style quartz-polymetallic sulphide veins with up to 5 per cent sphalerite-galena-chalcopyrite. This extensive veined interval encompasses a 25.4-metre-thick drilled interval (488.2 to 513.6 metres) with length-weighted average grades of 2.12 grams per tonne gold, 4 grams per tonne silver, 0.17 per cent zinc, and 0.13 per cent lead plus anomalous arsenic and antimony.

In 2017, Ten drill holes completed by Eskay Mining Corp targeted the CCTF footwall rocks, while two holes targeted a potential northern extension of known mineralization in the CCTF hangingwall (LULU zone). Chlorite-sericite alteration consistent with volcanogenic massive sulphide (VMS) footwall alteration was also present in every hole drilled, and local sulphide-bearing veining was intersected in several holes. The assays to date, although low-grade, do show mineralizing systems are present.

Drill hole EK17-144 (from 672.49-674 metres) contained quartz-carbonate veins with sericite altered envelopes that yielded 2.25 grams per tonne gold over 1.51 metres (Eskay Mining Corp. News Release, October 19,2017). In drill hole EK17-149 (from 386.88-410.08 metres) contained numerous polymetallic sulphide (pyrite, pyrrhotite, sphalerite, galena, plus/minus chalcopyrite and arsenopyrite) veins, up to 10 centimetres thick, accompanied by abundant stringers and disseminations of red to brown sphalerite in rhyolitic groundmass.

In 2018, drillhole EK-160 yielded 0.80 gram per tonne gold over 109 metres, including 61.9 grams per tonne gold over 1 metre (Assessment Report 38315).

Work History

Consolidated Silver Butte (SIB) and its predecessor companies were active on the SIB from the 1930s until the early 1990s. In 1989, 1990 and 1991 Copeland Rebagliati & Associates Ltd. (and its predecessor company Coastal Mountain Engineering & Management Ltd.) conducted exploration on the SIB claims on behalf of American Fibre Corporation and Silver Butte Resources Ltd. Later, Heritage Exploration (now St. Andrew Goldfields, SAS) applied a systematic and multidisciplinary approach to its exploration at the core SIB property (including the Lulu and Hexagon zones) in the period 2001 to 2003. Those programs involved aggressive drilling of targets developed by geological mapping, geochemical sampling (stream sediments), lithogeochemical sampling (rocks), and airborne geophysics (AeroTEM II). In aggregate, the historical exploration programs completed a total of 132 diamond drill holes, comprising 19,417 meters of diamond drilling. Most of the historical drilling was targeting the mudstone horizon at the Lulu zone. Historical interpretation of the results concluded that the Coulter Creek Thrust Fault limited the exploration of the Lulu to the south, and at depth.

Kenrich-Eskay Mining Corp optioned the Property in May 2008. The 2008 exploration program comprised geological mapping and lithogeochemical sampling, along with 4 drillholes for 2,333.6 metres of drilling. Geological mapping was conducted on the surface over the SIB claims to tie the SIB lithologies into the mapping scheme of the more advanced geological work from the 2003-08 Corey programs. That early summer 2008 work confirmed the validity of the drill targets lying in the footwall of the Coulter Creek Thrust Fault, an untested region of the SIB claims. Three of the four diamond drill holes of the 2008 program targeted the footwall to the Coulter Creek Thrust Fault, each intersecting Salmon River formation rocks of the Eskay-type geological signature.

The 2008 diamond drilling program was targeted at “Lulu horizon” mineralization within stratigraphically equivalent mudstone in the footwall of the Coulter Creek Thrust Fault, beneath the overthrusted Betty Creek formation rocks. Drillholes EK08-132, 134 and 135 were planned to locate the fault displaced segments of the Lulu Zone stratigraphy in the footwall of the Coulter Creek Thrust Fault.

The most significant mineralization was obtained from hole EK08-134. That hole passed through the Coulter Creek Thrust Fault (CCTF) at 458 metres depth. The interval between 488.2 and 513.6 metres is a pale grey-green Eskay-type tholeiitic rhyolite intrusive into mudstone, and in part flow banded. Notably, thin, anastomosing quartz-polymetallic sulphide veins cut this unit. These locally carry up to 15 per cent sphalerite-galena-chalcopyrite-pyrite. Additionally, there are thicker, laminated “stockwork” style quartz-polymetallic sulphide veins with up to 5 per cent sphalerite-galena-chalcopyrite. This extensive veined interval encompasses a 25.4-metre-thick drilled interval (488.2 to 513.6 metres) with length-weighted average grades of 2.12 grams per tonne gold, 4 grams per tonne silver, 0.17 per cent zinc, and 0.13 per cent lead plus anomalous arsenic and antimony.

In 2010, Eskay Mining Corp drilled five holes, 700 to 800 metres deep, in search of the fault-displaced continuation of Eskay-type stratiform gold and silver-rich massive sulphides. Very little significant mineralization was found. In drill hole EK10-138 below the CCTF, a two-metre interval contained 5 per cent pyrite-sphalerite-galena stringers within a sheared and veined argillite unit. Within this, a 0.9-metre interval from 556.9 to 557.8 metres depth assayed 0.06 gram per tonne gold, 0.2 per cent lead, 0.5 per cent zinc and five grams per tonne silver (Eskay Mining Corp., News Release, November 22, 2010).

In 2017, Eskay Mining Corp./SSR Mining Inc completed a 9,335-metre, 12-hole diamond drill program on its SIB property. SSR Mining Inc. had the option to earn a 51-per-cent undivided interest in the property. Drilling returned no economic concentrations of precious metals but did succeed in confirming the presence of Eskay Creek equivalent stratigraphy in the footwall of the Coulter Creek Thrust Fault (Assessment Report 37389).

In 2018 SSR Mining completed a 9128 metre drill program focused on identifying precious metals enriched volcanic associated massive sulphide (VMS) mineralization and associated feeder systems hosted within Eskay Member rhyolite of the Salmon River Formation. Assay results were encouraging with hanging wall holes EK18-158 and EK18-160 both intersecting similar broad zones of anomalous gold and base metal mineralization. Polymetallic sulfide veining was dominantly hosted within intensely silica altered intermediate volcanics of the Betty Creek Formation. This is interpreted to represent feeder systems to a possible VMS deposit up stratigraphy (Assessment Report 38315).

In 2020, Eskay Mining Corp. completed a program of prospecting, rock sampling, ground and airborne geophysical surveys and 4335 metres of diamond drilling in 20 holes on the area as part of the Sib-Corey-North Mitchell property. The geophysical surveys consisted of a 911.7 line-kilometre airborne electromagnetic survey, a 55.85 line-kilometre induced polarization survey and a 43.19 line-kilometre magnetotelluric survey. Drilling was performed on the TV (MINFILE 104B 385) and Jeff (MINFILE 104B 525) occurrences.

Bibliography
EMPR BULL 63
EMPR EXPL *1989, pp.197-223; 2008, p.24; 2010, p.46; 2017-134
EMPR FIELDWORK 1988, pp. 241-250
EMPR OF 1989-10; 1999-2; 1999-14
EMPR PF (Research Quarterly Update for St. Andrew Goldfields Ltd., January 21, 2003)
GSC MAP 9-1957; 1418A
GSC P 89-1E, pp. 145-154
CMJ Heritage Explorations Ltd, August 13, 2003
GCNL #229 (Nov.), 1991
N MINER Dec.2, 2002
N MINER Vol.88, No.33, Oct.7-13, 2002
PERS COMM J.M. Britton (1991)
PR REL Heritage Explorations Ltd., Sep.12, Nov.19, 2002; Sep.2, 2003 Eskay Mining Corp Nov.22, 2010; Oct.17, 2016; Aug.2, Oct.19, 2017
Donnelly, D.A. (1976): Study of the Volcanic Stratigraphy and Volcanogenic Mineralization on the Kay claim group, Northwestern British Columbia, Unpublished B.Sc. Thesis, University of British Columbia, 61 pages
Gunning, M.H. (1986): Late Triassic to Middle Jurassic (Norian to Oxfordian) Volcanic and Sedimentary Stratigraphy and Structure in the Southeastern part of the Iskut map sheet, North-Central British Columbia, Unpublished B.Sc. Thesis, University of British Columbia, 85 pages.
*Statement of Material Facts #42-91, May 24, 1991 - Summary Report on the Sib Claims (March 11, 1991)
Lindsay, D., Prowse, N.D. (2021-06-08): NI 43-101 Technical Report on the Sib-Corey-North Mitchell Property

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