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File Created: 24-Jul-85 by BC Geological Survey (BCGS)
Last Edit:  10-Mar-89 by Wim S. Vanderpoll(WV)

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NMI 092L2 Au16
Name CENTRAL ZEBALLOS, BIBB, EXTENSION NO. 6 (L.1049), RENO GOLD, AE, AD, B2-B6, M2,5,6, MON FRACTION Mining Division Alberni
BCGS Map 092L007
Status Past Producer NTS Map 092L02W
Latitude 50º 02' 09" N UTM 09 (NAD 83)
Longitude 126º 47' 00" W Northing 5544969
Easting 658737
Commodities Gold, Silver, Lead, Copper, Zinc Deposit Types I01 : Au-quartz veins
I06 : Cu+/-Ag quartz veins
Tectonic Belt Insular Terrane Wrangell, Plutonic Rocks
Capsule Geology

The Central Zeballos mine lies in the Zeballos gold camp which is underlain by the Lower Jurassic Bonanza Group. The Bonanza Group consists of a sequence of basaltic to rhyolitic volcanic rocks. Conformably underlying the Bonanza Group are limestones and limy clastics of the Quatsino and Parson Bay formations, and Karmutsen Formation tholeiitic basalts, all belonging to the Upper Triassic Vancouver Group. Dioritic to granodioritic plutons of the Zeballos intrusion phase of the Early-Middle Jurassic Island Plutonic Suite have intruded all older rocks. The Eocene Zeballos stock, a quartz diorite phase of the Tertiary Catface Intrusions, is spatially related to the areas gold-quartz veins. Bedded rocks are predominantly northwest striking, southwest dipping, and anticlinally folded about a northwest axis.

Recorded production for the Zeballos gold camp totals 9465 kilograms of gold and 4119 kilograms of silver from 652,000 tonnes of ore mined (Fieldwork 1982, page 291). Most of the production came from the Spud Valley deposits (092L 013 and 092L 211) and the Privateer mine (092L 008).

The area of the Central Zeballos mine is underlain by dark- coloured granodiorite near its gradational contact with a lighter coloured, border phase of granodiorite and quartz diorite. Roof pendants or inliers of calc-silicate rocks, skarn-altered limestone and dark green andesite of the Quatsino Formation and Bonanza Group are present nearby.

The Central Zeballos vein lies in a 0.6 by 1.8 kilometre east-west body of porphyritic granodiorite of the Island Plutonic Suite. The light coloured border phase of the southern margin has a slightly schistose texture. This phase contains less biotite, and in the ground mass the orthoclase content is higher than plagioclase, as compared to the darker phase, which it has intruded. Contact relationships and distribution between the two granodiorite phases are indefinite. Inclusions of volcanic rock ranging up to 7 metres in width are present within the granodiorite.

West and below the granodiorite lies quartz diorite of the northwest trending South Zeballos pluton. Small dykes of quartz diorite have invaded granodiorite for short distances from the contact. Diabase dykes are present only in the layered rocks. Carbonate-sericite altered porphyritic dacite dykes, from several centimetres to 7 metres wide, occur in quartz diorite and granodiorite. Felsic dykes of less than 10 centimetres width cut quartz diorite and locally attain stockwork frequency.

The Central Zeballos vein has been explored and developed along a strike length of 450 metres and downdip for 340 metres. It occupies a well-defined west striking, 75 to 80 degree south dipping shear zone 7 to 45 centimetres wide containing quartz and strongly sheared country rock and gouge. Northeast trending diagonal joints interrupt the continuity of the vein. These joints may offset or briefly redirect the vein. The main shear locally splits into two or more breaks over a space of 1.2 metres, running parallel for as much as 15 metres before converging. Post-vein movement along the shear is indicated.

The best mineralization occurs in the wider sections of quartz, usually 20 to 25 centimetres, where comb structures and well-formed quartz crystals may be present.

Alteration of wallrock extends only a few centimetres from the shear. In the granodiorite, where most of the mineralization is located, alteration consists of bleaching with sericite, kaolin and quartz.

Banwolt (Geological Survey of Canada Paper 40-12, page 29) emphasizes the fact that the vein and shear zone follow, to a large degree, the path of an aplite dyke. The dyke has been shattered in places, its fragments cemented by quartz and sulphides.

Intermittent mining between 1938 and 1947 developed 10 levels, sublevels and related raises, winzes and crosscuts, and produced 37,789 tonnes of milling ore averaging 16.85 grams per tonne gold, 11.44 grams per tonne silver, 0.02 per cent copper and 0.19 per cent lead.

Possible reserves are 43,631 tonnes grading 12 grams per tonne gold and are estimates based on results from old mine data as supported by recent underground sampling and diamond drilling. The estimated grade given is based on historical data and not from current point sampling. Probable reserves are 8163 tonnes grading 12 grams per tonne gold and are estimates where indicated by compiling results of recent underground sampling with old mine data (Statement of Material Facts, Consolidated Impact Resources Inc., Report by J.C. Freeze, June 1989).

Bibliography
EMPR AR *1938-38,39,43-45; 1939-40,42,88; 1940-72; 1941-A27,70;  1942-28,65; 1946-36,179,295; 1947-180-181
EMPR ASS RPT 12077, 18556, 18577, 18770
EMPR BULL 20 Part V, pp. 16-20; *27, pp. 15, 104-112
EMPR ENG INSP Fiche Numbers 60270-60273
EMPR EXPL 1979-188; 1983-330
EMPR FIELDWORK 1982, p. 290; 1983, p. 219
EMPR GEM 1970-255; 1937-1953
EMPR MAP 65 (1989)
EMPR OF 1992-1
EMPR PF (Starr, C.C. (1939): Report on the Central Zeballos Gold  Mines Ltd., 9 p.; Central Zeballos Gold Mines, Claims and Surface  Geology (1"=300'), 1939; Starr, C.C. (1947): Report on the  Central Zeballos Mine, 6 p.; Central Zeballos Mine, Section on  East-West Plane (1"=100'), 1947; Central Zeballos Gold Mines,  Claim sketch (1"=600'), 1947; Starr, C.C. (1939): Central  Zeballos Gold Mine, article in Northern Miner, April, p. 37;  J.C. Freeze, Geological Report, June 1989; M.C. Hansen and  A.J. Sinclair, Preliminary Resource Assessment, undated)
EMR MP CORPFILE (Central Zeballos Gold Mines Ltd.; Reno Gold Mines  Ltd.)
GSC EC GEOL 1 (1947)
GSC MAP 4-1974; 255A; 1028A
GSC MEM 204; 272, pp. 48, 63
GSC OF 9; 170; 463
GSC P 38-5; 40-12, p. 30; 69-1A; 70-1A; 72-44; 74-8; 79-30
GSC SUM RPT 1929 Part A; 1932 Part A
CIM Transactions Vol.42 (1939), pp. 225-237; 1948, pp. 78-85; 72,  pp. 116-125
GCNL #299, 1980; #53,#128, 1981; #42,#174, 1982; #87,#189, 1983;  #190,#202,#213,#231,#248, 1988; #11,#24,#45,#52,#93(May  15),#134(Jul.13),#207(Oct.27), 1989
N MINER Apr., 1938, pp. 39-45; Dec.19, 1988
NW PROSP Oct./Nov., 1988
V STOCKWATCH Jul.3, 1987
WWW
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

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