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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  30-May-14 by Nicole Barlow(NB)

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NMI 093K8 Sb1
Name SNOWBIRD, MCMULLEN, STUART LAKE ANTIMONY MINE, BAY, NORTH, EAST, SOWCHEA, PEGLEG Mining Division Omineca
BCGS Map 093K048
Status Past Producer NTS Map 093K07E
Latitude 54º 27' 10" N UTM 10 (NAD 83)
Longitude 124º 30' 28" W Northing 6034946
Easting 402245
Commodities Gold, Antimony Deposit Types I01 : Au-quartz veins
I09 : Stibnite veins and disseminations
Tectonic Belt Intermontane Terrane Cache Creek
Capsule Geology

The Snowbird property is located 16 kilometres west of Fort St. James, near the southern shore of Stuart Lake.

Gold-antimony mineralization at the Snowbird property occurs within the Carboniferous-Jurassic Cache Creek Complex (Group) of the allochthonous Cache Creek terrane, which is truncated to the east by the Pinchi fault, a complex, northwesterly trending, transcurrent fault system. Northeast of the fault zone, the Upper Triassic Takla Group is composed of greywacke and siltstone with minor conglomerate and limestone. Southwest of the fault zone, the Cache Creek Complex is composed of chert, argillite, basalt, alpine-type ultramafics, extensive carbonates and minor blueschist.

The dominant structural feature at the Snowbird property is the Sowchea shear zone, a zone of brecciation and open-space fracturing up to 50 metres wide, which strikes north westerly and dips 40 to 50 degrees northeasterly. Multiple episodes of ankerite and silica flooding over a strike length of at least 1200 metres have produced a classic listwanite lithology along the shear zone, comprised of ankerite, quartz and mariposite.

North and south of the shear zone, the listwanites grade into a steeply dipping, silicified, carbonaceous argillite sequence. Occurrences of diorite-andesite intrusions in the argillite may be associated with the granite-diorite Early Jurassic-Late Triassic Topley Intrusions, which crosscut the Cache Creek Complex. The McKnab Lake pluton is 166 Ma, mariposite is approximately 162 and sericite show Snowbird stock is 157 Ma.

The gold-antimony mineralization is associated with the Sowchea shear zone whose permeability appears to have controlled the vertical and lateral extent of mineralization. Three sulphide-bearing quartz veins occur (Economic Geology 85).

The Main vein is located in the hanging wall of the shear zone. It strikes 120 degrees with a dip of 40 to 50 degrees to the northeast. Trench sampling along 64 metres of the Main vein has yielded gold assay values that average 4.45 grams per tonne across an average width of 0.9 metre (Economic Geology 85). Figure 3.7, Bulletin 108 shows 20.02 grams per tonne and 21.84 grams per tonne gold on drill fragments (10 centimetres?).

The Peg-leg vein is located in the footwall of the shear zone. It strikes at 120 degrees with a dip of 40 to 50 degrees to the northeast. Trench sampling along 66 metres of the Peg-leg vein has yielded gold assay values of 13.03 grams per tonne across an average width of 0.8 metre (Economic Geology 85). A 10-centimetre drill core yields 8508 grams per tonne gold and 2900 grams per tonne silver (Bulletin 108, page 37).

A third vein, which crosses into the argillites is stibnite rich and strikes at 010 degrees, approximately at a right angle to the Sowchea shear zone.

Carbonate (ankerite)-quartz-mariposite listwanites are fine to medium-grained, dark olive green to grey-coloured rocks with centimetre-scale patches of bright apple-green mariposite. Some samples have a greasy-soapy feel suggesting the presence of talc. An extensive network of ferroan magnesite and quartz veinlets and stringers crosscut the rocks. Mariposite is found most often as an alteration product of chromites. Chromite is fractured, fragmented, and suggests an alpine-type ultramafic. Remnant olivine, extensively altered to serpentine family minerals (usually chrysotile or antigorite) and magnetite, is present in several thin sections (Economic Geology 85).

In the Main vein, stibnite mineralization is sporadically distributed as pods or vuggy fillings in fractured, milky white quartz gangue. The mineralogy of the quartz-sulphide veins generally consists of three sulphide minerals, stibnite, arsenopyrite and trace amounts of anhedral pyrite, occurring in the quartz gangue. Anhedral stibnite is intimately embayed with the quartz, fills interstices within it, and often appears to replace it. Clusters of subhedral arsenopyrite are found either within the anhedral quartz gangue or intermixed with the stibnite.

Deposition of stibnite-bearing quartz veins at the Snowbird property occurred after pervasive listwanitization along the Sowchea shear and complex, greenschist facies metamorphism of the Cache Creek Complex during the Jurassic. Several geologic characteristics of the Snowbird occurrence are similar to other documented mesothermal deposits (Economic Geology 85).

Massive stibnite was first discovered in a shear zone on the Snowbird property in 1920 by placer prospectors in the area. In 1937, a shipment of 48.9 tonnes of (unknown grade) antimony ore was produced from underground workings. In 1939, Pioneer Gold Mines Limited optioned the property and sunk a 45 metres shaft on the “Main Vein” and a 45-metre adit on the massive stibnite “Cross Vein”. During this time 32.6 tonnes of ore (unknown grade) was shipped. In 1947, Cominco acquired the property and shipped a total of 59.9 tonnes of massive stibnite (unknown grade) from the “Cross Vein”. An ore shoot sampled at this time returned 8.58 grams per tonne gold and 9.2 per cent antimony over 28.5 metres length and 0.9 metres wide (Property File Rimfire Minnova Inc., 1990).

The property lay dormant until 1970 when a geochemical survey was completed on a small portion of the property. In 1974 and 1980 a small amount of drilling was completed on the quartz stringer zones with the best intersection returning 12.01 grams per tonne gold over 1.5 metres (Property File Rimfire Minnova Inc., 1990).

X-Cal Resources Limited optioned the property in 1985 and completed a trenching, geochemical sampling and a ten-hole diamond drilling programme in 1986. The drilling centered on the “Main Vein” and “Pegleg Vein”. The best assayed intersection returned 9.26 grams per tonne over 4.25 metres. A separate hole (85-6) intersected a vein 0.15 metres wide containing visible gold, assaying 8511.89 grams per tonne gold and 2901.1 grams per tonne silver (Property File Rimfire Minnova Inc., 1990).

During 1987, a comprehensive geophysical survey comprising IP, horizontal loop EM, VLF-EM and magnetics was completed over the northwest portion of the property. The IP survey located and extended the known zone of alteration to 2000, metres at this time. This was followed by twenty-five diamond-drill holes and fifty-seven percussion drillholes on the same area as in 1986. Diamond drilling in, 1988, extended the known zone of gold mineralization in the structure an additional 370 metres. Intersections included 2.65 metres of 7.75 grams per tonne gold and 6.12 metres of 10.94 grams per tonne gold (Property File Rimfire Minnova Inc., 1990).

In 1994, X-Cal Resources completed airborne electromagnetic and magnetic surveys. In 2003, a program of geological mapping and sampling was completed. A sample (SB-03-02) from the main shaft assayed 3.67 grams per tonne gold and greater than 0.2 per cent antimony, while another sample (SB-03-01) from the mariposite alteration zone assayed 0.115 per cent antimony and 0.916 gram per tonne gold (Assessment Report 27154).

In 2011 and 2012, Omineca Gold completed a program of geological mapping, rock sampling and historical data review.

Unclassified reserves at Snowbird are 4535 tonnes grading 6.86 grams per tonne gold and 3.0 per cent antimony (News Release, X-Cal Resources, October 9, 1986). Possible reserves in the North zone are 226,775 tonnes grading 6.86 grams per tonne gold (Northern Miner - March 27, 1989).

Approximately 78 tonnes of stibnite ore were mined from the Snowbird property between 1938 and 1940 (Economic Geology 85).

Bibliography
EMPR AR 1929-186; 1939-99; 1963-38
EMPR ASS RPT 520, 2764, 3520, 5136, *8613, *15261, 15732, *15853, *16766, 23523, *27154, 33310
EMPR BULL 108, p. 27-40
EMPR EXPL 1980-337; 1986-C346; *1987-C296,B47,B48; *1989-171-174; 1992-69-106
EMPR FIELDWORK 1992, pp. 69-86, 475-482
EMPR GEM 1970-117; 1971-166; 1974-254
EMPR MAP 65 (1989)
EMPR MIN POT MAP 1993-2
EMPR OF 1992-1; 1993-9
EMPR PF (Fort Fraser Mineral Occurrence Map to accompany GSC Paper 38-14; Geology Stuart Lake Area, 1940; Stevenson, J.S. 1939 Notes on Snowbird Property; Rough Geological Map assumed Snowbird Area, 1940; James, D.H. 1963 Report on Magnetometer Survey; Trench Locations, Consolidated Shunsby Mines Ltd., 1971; Claim Map, 1971; Dept. of Mines Summary of Exploration and Development work, 1972, 1975; X-Cal Resources Quarterly Report Nov. 1986; Articles (unidentified source) Jan. 1987; Quarterly Report Jan. 22, 1987; Shareholders Quarterly Aug. 27, 1987; X-Cal Resources Ltd. Annual Report 1987; X-Cal Resources Annual Report 1989; Progress Report X-Cal Resources Ltd. Feb. 1989; X-Cal Resources Circular Apr.8, 1989; Yorkton Natural Resources, Circular Issue #22, May 1, 1989)
EMPR PF Placer Dome (Drillhole Cross-Section Maps - Snowbird Property; C.J.S. (1989-01-08): Geology map, East sheet, Snowbird Property; C.J.S. (1989-01-08): Geology map, West sheet, Snowbird Property)
EMPR PF Rimfire (Macrae, R. (1958-05-13): Re: Stuart Lake Antimony Prospect; Minnova Inc. (1990-11-06): Re: X-Cal Resources Ltd. Snowbird Gold Project, Bralorne Gold Project)
EMR MR CORPFILE (Pioneer Gold Mines of B.C. Limited; Tungsten of British Columbia, Ltd.; Consolidated Shunsby Mines Limited; Westwind Mines Ltd.; X-Cal Resources Ltd.)
EMR MR MIN BULL 223 B.C. 224
EMR MP RESFILE (British Columbia)
GSC MAP 630A; 907A; 971A; 1424A
GSC MEM *252, pp. 186-189
GSC OF 2593, 3182
GSC P 38-14, p. 7; 90-1F, pp. 115-120; 91-1A, pp. 7-13
ECON GEOL *85 (1990), pp. 1260-1268 (Madu, B.E., Nesbitt, B.E. and Muehlenbachs, K.)
GCNL #133, #215, 1980; #59, #146, 1981; #67,#197, 1986; #10,#24,#47, #108,#208, 1987; #40,#73,#191, 1988; #6(Jan.10),#10(Jan.16),#33, #47,#148(Aug.2),#167(Aug.30), 1989; #143(Jul.25), 1990; #9(Jan.14), 1991
N MINER Apr.21, Aug.8, Oct.20, Dec.8, Dec.22, 1986; Jan.26, Feb. 2, Feb.9, Mar.23, 1987; Mar.6,27, Aug.14, 1989
NW PROSP Jan. 1987; Jan/Feb, Mar/Apr, May/June, 1989
PR REL X-Cal Resources Oct.9, 1986; Jan.12, Feb.2, June 2, July 20, Oct.26, 1987; Feb.10, Apr.8, 1989
TSE Review Oct. 1987
Placer Dome File

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