Grande Portage Resources Ltd. (GPTRF)

[Mr. Zen]

a few more research notes on the Merry Widow area

The Merry Widow deposit occurs as 3 stacked lenses containing massive magnetite within Lower Jurassic Bonanza Group volcaniclastics and underlying Upper Triassic Vancouver Group, Quatsino Formation limestone. The occurrence lies several hundred metres east of the diorite to gabbro Coast Copper or Benson Lake stock of the Early to Middle Jurassic Island Plutonic Suite.

The sediments and volcanics are north to northwest striking and west dipping. The intrusion has locally modified attitudes. The north striking intrusive contact dips 90 to 70 degrees eastward; but in the vicinity of the open pit it dips only 55 degrees east. Contact metamorphism of limestone is limited to recrystallization, with destruction of bedding features. The volcanic rocks (clastics, pyroclastics and flows) are hornfelsed with local lenses of garnet- epidote-actinolite-diopside-chlorite skarn. Intrusive greenstone sills, dykes and masses, and crosscutting dykes of andesite, alaskite, diabase and granodiorite are present. Northeast trending faults, dipping south, predominate.

The upper lens of the main deposit occurs as two distinct ore zones, separated laterally by about 30 metres of unmineralized skarn. The upper lens measures 104 metres in diameter, is 17 metres thick and dips 30 degrees east. Limestone abruptly terminates the mineralization down dip.

The middle lens is separated from the upper by 12 metres of barren, skarned volcanic rock through which passes a flat-lying thrust fault. The middle lens is 85 metres wide and 9 metres thick.

The lowermost lens lies along the gabbro contact and separated from it by a thin skarn rind. It has been explored for 165 metres down dip, where the lens thins considerably from a 12-metre maximum width near its upper limit (Property File - J.C. Lund, 1966).

Magnetite mineralization in the lenses is massive, with sharp contacts where enclosed by limestone. Contacts with volcanic and intrusive rocks are less distinct, with disseminated magnetite occurring at some distance away from the massive lenses, giving a gradational change in magnetite distribution. Bedding structures can in places be traced into magnetite. Ore locally passes outward into stringers along bedding planes or follows dykes and sills in limestone. Botryoidal structures are present, suggesting emplacement at low pressure and temperature by "gel metasomatism" (Open File 1988-28, page 44).

Small amounts of arsenopyrite with pyrrhotite, sphalerite, marcasite, cuprite, chalcopyrite and calcite are reported. A north striking fault south of the open pit hosts small amounts of iron and copper sulphides and cobaltite with cobalt bloom (erythrite). Minor pyrite, chalcopyrite and pyrrhotite accompanied by quartz are present. Jefferey (Minister of Mines Annual Report 1960, page 97) believes this latter mineralization to be later than the magnetite, and that the orebody is the result of successive mineralizing periods of silicates (skarn), oxides, sulphides and carbonate emplacement. Commercial ore has developed where the intrusive contact has locally the lowest dip, and where the bulge in the intrusion has caused a change in the strike of the layered rocks. In addition, northeast striking faults are believed to localize mineralization (Minister of Mines Annual Report 1960, page 97).

The limestone in the vicinity of the magnetite bodies is white to grey in colour and calcium high calcium in composition. Three limestone samples collected by Taywin Resources Ltd. in 1990, while exploring for precious metal bearing skarn zones, analyzed as follows in per cent (Industrial Mineral File - J.M. Huber Corp., 1990):

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CaO 53.67 54.57 52.89

MgO 1.81 0.10 2.32

SiO2 0.45 0.14 0.02

Acid Insol. - 2.22 0.60

Al203 0.06 - -

Fe2O3 0.06 - -

MnO 0.02 - -

K2O 0.01 - -

Na2O 0.01 - -

P2O5 0.01 - -

TiO2 0.11 - -

Brightness:

Green Filter - 91.8 93.8

Blue Filter - 92.2 93.6

Amber Filter - 89.0 91.1

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An article in the George Cross Newsletter No. 80 (1989) indicates the presence of gold and silver values. Dixon (1989) reports the presence of tellurobismuthite. Gold is found in pyrrhotite-pyrite-rich veins and pockets that postdate the magnetite. A sulphide-rich sample assayed up to 17 per cent copper, 2.9 per cent zinc, 0.2 per cent arsenic, 0.16 per cent cobalt, 200 grams per tonne silver and 32 grams per tonne gold (EMPR Bulletin 101, Appendix 4A).

Production between 1957 and 1967, was from both surface and underground, and included ore from the Kingfisher (092L 045) and Raven (092L 046). From 3,371,015 tonnes of ore mined, 1,676,060,554 kilograms of iron concentrate was shipped. Annual reports detail yearly ore produced. Iron content was about 58 per cent.


Bibliography EMPR AR 1913-282; 1916-341; 1918-475; 1919-371; 1924-225; 1928-375; 1929-379; 1930-296; *1952-228-231; 1956-117; 1957-A44,A48,68; 1958-A43,A48,57; 1959-A46,A50,132-133; *1960-A51,A56,90-100; *1961-A46,95-97; 1962-A47,A51,96-97; 1963-A47,A51,100; 1964-A53, A57,152; 1965-229; 1966-A48,A50,66; 1967-A50,A53,70-71
EMPR ASS RPT 1760, 2306
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EMPR EXPL 1989, pp. 141-145; 1992-51; 2002-29-40
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EMPR MAP Preliminary Geological Map Alice Lake-Benson Lake Area, Jeffery, W.G., 1962
EMPR OF *1988-28; *1991-8; 1992-18, pp. 30-31
EMPR P *1989-3, pp. 56-58, 109; 1991-4, p. 228
EMPR PF (Claims of the Quastino Copper Gold Company Ltd.; Diamond drill sections, cross-section; Kingfisher and Merry Widow orebodies, Pit outlines, Mannix Co.; J. Lamb: Untitled reports, 1959, 1961; W.G. Jefferey & G.E.P. Eastwood: Field Report, (1961): Magnetite Occurrences in Benson Lake Area; J.C. Lund, (1966): Structural Geology of Empire Mine, M.Sc. Thesis, University of British Columbia; J.M. Huber Corp. (1990): Calcium carbonate division - laboratory data systems; private analytical report for Taywin Resources Ltd., 2 pages; Dixon, K. (1989): A Mineralogical Study of the Merry Widow Property, Vancouver Island; unpublished paper, the University of British Columbia; Taywin Resources Ltd., Diamond Drilling Report, July 1989; Taywin Resources Ltd., Geology of the Merry Widow, undated; Regional Geologist's Letter (Oct. 92) and notes (Jan.1991); Photos, 1992)
EMR MIN BULL 181 (1978) B.C. 121; 223 (1989) B.C. 175
EMR MP CORPFILE (Quatsino Copper-Gold Mines, Ltd.; Empire Development Co. Ltd.)
GSC BULL 172, p. 63
GSC MAP 4-1974; 255A; 1552A
GSC OF 9; 170; 463
GSC P 69-1A; 70-1A; 72-44; 74-8
GSC SUM RPT 1918 Part B, p. 35; 1929 Part A, p. 126
ECON GEOL Vol. 59, pp. 1298-1305; Vol. 60, pp. 124-148; Vol. 79, pp. 869-882
GCNL #80,#138(July 19),#132(July 11),#189(Oct.2),#205(Oct.25), #207(Oct.27), 1989; #58(Mar.23), #95(May 15),#135(July 15), 1992
N MINER Apr.27, 1992
PR REL Taywin Resources Ltd., June 15 and July 6, 1989 (located in Property File)
WWW http://www.infomine.com/index/properties/MERRY_WIDOW.html
Carson, D.J.T. (1968): Metallogenic study of Vancouver Island with emphasis on the relationship of plutonic rocks to Mineral deposits, Ph.D. Thesis, Carleton University, Ottawa
Dixon, K. (1989): A Mineralogical Study of the Merry Widow Property, Vancouver Island; unpublished paper, The University of British Columbia
Hudson, R. (1997): A Field Guide to Gold, Gemstone & Mineral Sites of British Columbia, Vol. 1: Vancouver Island, p. 187
Placer Dome File
Sangster, D.F. (1964): The Contact Metasomatic Magnetite Deposits of Southwestern B.C., Ph.D. Thesis, University of British Columbia
Wittur, G.E. (1961): Geology of the Magnetite Deposits of Empire Development Co. Ltd., Vancouver Island, British Columbia, unpub. B.Sc. Thesis, University of British Columbia