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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  13-Jan-04 by Robert H. Pinsent(RHP)

Summary Help Help

NMI 082K11 Ag1
Name SILVER CUP (L.768), SUNSHINE (L.1564), SILVER CUP FRACTION (L.2622), COMSTOCK, COMSTOCK/AINSWORTH Mining Division Revelstoke
BCGS Map 082K064
Status Past Producer NTS Map 082K11W
Latitude 50º 38' 10" N UTM 11 (NAD 83)
Longitude 117º 22' 02" W Northing 5609425
Easting 474031
Commodities Silver, Lead, Zinc, Gold, Copper Deposit Types I05 : Polymetallic veins Ag-Pb-Zn+/-Au
Tectonic Belt Omineca Terrane Kootenay
Capsule Geology

The Silver Cup mine is at approximately 2000 metres elevation at the north end of Silver Cup Ridge. The host tenure, is one of a cluster of crown-granted claims that straddle a sharp ridge between Silver Cup Creek, which flows to the north into Lardeau Creek and Triune Creek, which flows to the northeast into the south branch of Lardeau Creek. The mine is at the head of the Silver Cup drainage and was served by a road and tramway down that creek to service point at Five-Mile east of Ferguson. The Silver Cup (L.768) tenure is bounded by the Gold Bug Fraction (L.3053) to the southwest and the Sunshine (L.1564) claim to the northwest. It is also bounded by the Silver Cup Fraction (L.2622) on the northeast and the Free Coinage (L.1588) on the southeast. The Free Coinage [082KNW109], Triune [082KNW026], Yuill [082KNW120] and Towser [082KNW028] occurrences are extensions of the Silver Cup mineral system to the southeast and northwest.

The Silver Cup orebodies were discovered around 1890 and they were mined almost continuously between 1895 and 1921. Thereafter, it operated intermittently in the 1930s and produced from its dumps into the 1980s. In total, the mine shipped 21,117 tonnes containing 45,278 grams of silver, 173,147 grams of gold, 485 kilograms of copper, 2,713,010 kilograms of lead and 213,197 kilograms of zinc.

The Silver Cup claim was originally owned by Messrs. Farrell and Dunn, and the neighbouring Sunshine claim was held by the Fraser River and Cariboo Gold Fields Company Limited. In 1895, they were combined under single management and since then, they have been worked as a single property. There was considerable development in the late 1890s when high-grade ore was sent by tramline to Five-Mile on Lardeau Creek for shipment. In 1902, a small stamp mill was built at Five-Mile and Ferguson Mines Limited made an unsuccessful attempt to process low-grade ore from the Silver Cup and nearby Nettie L. [082KNW100] mines. The Silver Cup mine closed in 1913. At that time, there were approximately 3650 metres of drift and crosscut on four adit levels, and eight internal levels, connected by shafts, raises and stopes. The No. 7 adit level was the main haulage way. It also linked the Sunshine and Silver Cup structures, was connected by a raise with the No. 4 level, and contained an internal shaft to the bottom, No. 12, level.

In 1937, a small flotation mill was erected at the Silver Cup campsite, on the Towser claim, and it processed ore from the dumps that year and again in 1941. In 1952, Yellowknife Bear Mines Limited had an option on the property and Granby Mining, Smelting and Power Company conducted some underground exploration and development work. The latter, dewatered the internal shaft between the No. 7 and No. 10 levels and diamond drilled ten holes to test areas below the No. 7 level. The bottom two levels were left flooded. Although some mineralization was found, the results were disappointing and Granby stopped the programme in 1953. Over the next few years, the mine passed through several different hands. In 1969, Silver Dawn Mines Limited acquired the property, sampled the upper adits and dumps and shipped a small sample. Since then, there has been little additional work (EMPR PF: MacKenzie Report for Mohawk Oil Co. Limited, 1972). The property was owned by True Blue Explorations Limited in 1972 and by C.T. Exploranda Limited in 1976. C.T. Exploranda also acquired the neighbouring Yuill [082KNW120] and Towser [082KNW028] properties to the north and it focused most of its attention on these adjacent properties. However, it also investigated what remained of the Silver Cup dumps. In 1980, it drove a drift from the Yuill adit southwest towards the main Silver Cup structure and drifted along it to the southeast.

The Trout Lake area is underlain by a thick succession of sedimentary and volcanic rocks of the Badshot Formation and Lardeau Group near the northern end of the Kootenay arc, an arcuate, north to northwest trending belt of Paleozoic and Mesozoic strata that is now classified as a distinct, pericratonic, terrane. The arc rocks are bordered by Precambrian quartzite in the east and they young to the west, where they are bounded by Jurassic-age intrusive complexes. They were deformed during the Antler orogeny in Devonian-Mississippian time and were refolded and faulted during the Columbian orogeny, in the Middle Jurassic. A large panel, the "Selkirk allochthon", was later offset to the northeast by dip-slip motion along the Columbia River Fault.

The Badshot Formation is composed of a thick Cambrian limestone that is a distinctive marker horizon in the Trout Lake area. It is underlain by Hamill Group quartzite and it is overlain by a younger assemblage of limestone, calcareous, graphitic and siliceous argillite and siltstone, sandstone, quartzite and conglomerate, and also mafic volcanic flows, tuffs and breccias, all of which belong to the Lardeau Group. The rocks are isoclinally folded and intensely deformed, but only weakly metamorphosed. They occur as intercalated beds of marble, quartzite and grey, green and black phyllite and schist. Fyles and Eastwood (EMPR BULL 45) subdivided the group into six formations (Index, Triune, Ajax, Sharon Creek, Jowett and Broadview) of which the lowermost (Index) and uppermost (Broadview) are the most widespread. The Triune (siliceous argillite), Ajax (quartzite) and Sharon Creek (siliceous argillite) are restricted to the Trout Lake area. The Jowett is a mafic volcanic unit. There are four principal veins on the Silver Cup property. They are known as the Main (Silver Cup) Lead, Blind Lead, Cross Lead and (near the entrance of the No. 7 adit) the Sunshine vein. The Main lead vein strikes at 145 degrees and dips steeply to the east. It consists of quartz with crushed silicified slate, pyrite, galena and graphite, and has sharp walls. The Blind lead vein is southwest of the Main lead and in its footwall. It is similar in composition and has the same orientation in the upper levels of the mine; however, it swings to a strike of 165 degrees below the No. 7 level. The walls of the vein are less well defined and the vein does not extend to surface. There are numerous sparsely mineralized stringers of quartz occupying fractures between the two zones and ore shoots commonly occur where minor cross-fractures intersect major veins. This is particularly evident in the footwall of the Blind vein and the hangingwall of the Main vein. The Cross Lead vein is similar in composition to the other two; however, it is less well defined. It strikes north and dips steeply to the east. The Sunshine workings are approximately 400 metres to the northwest of the main Silver Cup workings. The Sunshine vein also strikes north; however it has a shallow, 30 degree, dip to the east.

Approximately 95 percent of the ore produced at the Silver Cup mine came from the Main lead shoot, which is a well-defined lens with a maximum length of 100 metres, width of 61 metres and down dip extent of in excess of 365 metres. The lens strikes at 145 degrees, dips at 66 degrees to the northeast and pitches at 86 degrees to the northwest. It is in altered slates and shales of the Triune Formation and it both conforms to, and (locally) cuts, bedding at small angles. The shales overlie Index Formation phyllites in the core of a double anticline (two separated by a compressed syncline) that strikes at approximately 135 degrees and plunges to the northwest.

The structural geology of the area was studied by Trettin, in 1957 (EMPR PF: H. P. Trettin; Silver Cup Mine, Regional Frame-work and Structural Ore Control; M.Sc. Thesis, University of British Columbia; 1957). He notes that the Main and Sunshine leads are on the southwest limb of the southwest anticline and he considers that the exceptional size and depth extent of the main zone is a result of dilation caused by a combination of a drag folding and development of a compressional bulge in a mechanically brittle rock. The three other veins on the property were less well located structurally, and show less dilation. The schists and phyllites have been affected by lower-greenschist facies metamorphism and by widespread hydrothermal alteration. They were intensely carbonatized (Ca, Mg, Fe) and then silicified with the development of chromium mica (mariposite). The green and black phyllites of the Index Formation are more susceptible to alteration than the more siliceous Triune Formation strata.

The Main and Blind veins are composed of wall rock fragments, locally vuggy quartz, lesser carbonate and small amounts of sulphide. They are mineralized with pyrite, which carries sub-microscopic gold, galena and sphalerite. They also contain small blebs of chalcopyrite, argentiferous tetrahedrite, minor pyrargyrite, freibergite and arsenopyrite. Ore shoots within the two veins generally vary from a few centimetres to 1.5 or 3.0 metres in width.

The Sunshine vein is similar to the those found in the Silver Cup mine. It is at the contact between Triune Formation grey to black siliceous phyllite and Index Formation green phyllite, 365 metres northwest of the Silver Cup zone. Both units are mineralized. In the green phyllite of the Index Formation, subeconomic mineralization occurs in small fissures and faults that commonly strike to the northeast and dip to the southeast. In the more massive Triune Formation rocks, mineralization occurs in lenses between bulging planes of schistosity, which strikes to the northwest and dip to the northeast. The Sunshine stopes are short (3.0-7.6 metres long) and narrow (1.8 metres wide) but, like those on the Silver Cup vein, relatively long in a downdip direction (61 metres). Several small drag folds indicate relative movement of Triune Formation rocks to the northwest and one drag fold suggests upward movement of the hangingwall. The Sunshine X zone is northwest of the Sunshine lead. It strikes in a northeast direction and dips southeast, cutting the host rocks at a large angle. The zone is up to 2.1 metres wide and is in Index Formation green phyllite.

Although the Silver Cup mine was developed on a poly-metallic sulphide deposit, smelters charged a penalty for zinc in the early 1890s and sphalerite-rich "ore" was rejected and accumulated on the dumps. There are several on the mine property. In 1951, Hamilton estimated an indicated "reserve" based on four dumps of 37,191 tonnes averages 229.67 grams per tonne silver, 1.7 per cent lead, 1.5 per cent zinc and 2.74 grams per tonne gold (Hamilton, W.S. 1951). In 1977, C.T. Exploranda redefined the resource at 46,500 tonnes grading 1.37 grams per tonne gold, 252.7 grams per tonne silver, 1.2 per cent lead and 1.07 per cent zinc (Northern Miner, May 19th, 1977).

Bibliography
EMPR AR 1893-1049,1084; 1894-744; 1895-693; 1896-542; *1897-545,547,  548; *1898-1065,1193; 1899-602,681; *1900-815-817,822,823; 1901-  1018; 1902-H138,H140; *1903-H116-H121,H124; 1904-G116,G117; 1905-  J153; 1906-H136-H138,H249; 1907-L92,L214; 1908-J100,J101,J247;  *1909-K116,K117,K273; 1910-K101,K244; 1911-K154,K285; 1912-K151,  K323; 1913-K127,K420; *1914-K290,K301-K303,K510; 1915-K133; 1916-  K200; 1917-F191; 1920-N128; 1921-G161; 1928-C314,C435; 1936-E49;  1937-A40,A41,E56; 1939-A38; 1941-A26,A74; 1951-A179; 1952-A189,  A190; 1966-229,230
EMPR ASS RPT 7324, 9037, 17446
EMPR BULL 1 (1932), p. 113; *2 (1914), pp. 43,44; *45 pp. 75-78
EMPR ENG INSP (Underground plans-#61518)
EMPR EXPL 1976-E50; 1977-E69; 1978-E81; 1980-122
EMPR GEM 1969-341; 1970-466; 1971-429; 1972-77; 1973-95,96; 1974-25
EMPR OF 1998-10, 1990-24
EMPR P 1988-4
EMPR PF (Prospectus 1976, C.T. Exploranda Ltd; A.G. MacKenzie Report
on the properties of True Blue Explorations Limited (Silver Cup,
Towser and Yuill) for Mohawk Oil Co. Limited, December, 1972;
Eastwood, P. 1956: Plane table notes, rough notes; *Various geology
maps, plans (1956); *Trettin, H.P. 1957: Regional Framework and
Structural Ore Control of the Silver Cup Mine, Lardeau, M.Sc. Thesis,
University of British Columbia; *Hamilton, W.S. 1951-1953: Various
reports on the Silver Cup Property; Cannon, D.M. 1941: Report on the
Property of the Silver Cup Mine; CAN SUP File; 082KNW General: Sketch
map (1901), GCNL clippings; Starr, C.C. (1925): Report on the Silver
Cup Mine for Porcupine Goldfields Development and Finance Co. Ltd., 8
pages, workings 1"=100')
EMR MP CORPFILE (Silver Cup Mining & Milling Company, Limited; C.T.
Exploranda Ltd.)
GSC MEM *161 pp. 63-65
GSC OF 288; 432; 464
GSC SUM RPT 1903, pp. 66-68
CANMET IR MD 2898

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