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File Created: 22-Dec-91 by Chris J. Rees(CRE)
Last Edit:  07-May-97 by Chris J. Rees(CRE)

Summary Help Help

NMI
Name HANNAH 8,10,11, BIG FRANK, SAFFRON, BHA Mining Division Vancouver
BCGS Map 092N023
Status Prospect NTS Map 092N06W
Latitude 51º 17' 27" N UTM 10 (NAD 83)
Longitude 125º 24' 16" W Northing 5684913
Easting 332349
Commodities Gold, Silver, Copper, Molybdenum Deposit Types L04 : Porphyry Cu +/- Mo +/- Au
Tectonic Belt Coast Crystalline Terrane Plutonic Rocks
Capsule Geology

The Hannah occurrence is a showing of gold, silver, copper and molybdenum mineralization in altered intrusive rocks. It is located 1.5 kilometres southeast of Breccia Mountain, 25 kilometres north-northeast of the head of Knight Inlet.

The Hannah occurrence is within the Jurassic to Tertiary Coast Plutonic Complex (Geological Survey of Canada Open File 1163). The oldest rocks in the area of the occurrence are Mesozoic foliated granodiorite and quartz diorite. These are overlain by intermediate volcanic agglomerate and flows. All rocks are intruded by a Tertiary(?) biotite quartz monzonite stock, which is altered and mineralized and is the most economically important rock unit. The youngest rocks are outliers of unaltered, post-mineralization volcanic tuffs in the northwest of the area, which are probably the continuation of the Tertiary intrusive-extrusive complex that is well documented at the Hoodoo North occurrence (092N 029), 15.5 kilometres to the west-northwest.

The quartz monzonite stock intruded the dioritic rocks along a north-northwest trending structural lineament; the contacts are highly fractured. The stock is cut by numerous mafic to felsic dykes, typically intermediate feldspar porphyry, thought to be comagmatic with the stock (Assessment Report 18202).

The quartz monzonite stock itself is also fractured, and has pervasive hydrothermal alteration, primarily clay (argillic) and sericitic alteration of feldspars, and silicification. Associated quartz-pyrite stockwork veining may be accompanied by chalcopyrite, molybdenite and locally by minor specularite, magnetite and chlorite. The main altered area is described as "hybrid rocks", and is attributed to metalliferous hydrothermal fluid migration along contacts and late-stage fractures (Assessment Report 8744). Assay results from channel and chip samples (total 64) revealed that gold and molybdenum were more significant than copper and silver: the average assay for gold was 1 gram per tonne (maximum 11.3), and for molybdenum was 0.087 per cent (maximum 1.25) (Assessment Report 8744).

An important area is the Discovery zone where a shear zone in the quartz monzonite stock is intruded by felsic to intermediate porphyritic dykes (Assessment Report 18202). The area is marked by anomalous copper, molybdenum, silver and gold, and by a magnetic low and a Very Low Frequency (VLF) electromagnetic conductor; the report cited suggests the anomaly and alteration zonation are typical of a porphyry copper-molybdenum environment. The rocks are highly fractured, altered, veined, and mineralized with pyrite, chalcopyrite and molybdenite, associated with secondary quartz and carbonate. The zone has been explored by diamond drilling and trenching; one 1 metre section in a trench assayed 18 grams per tonne gold, 44 grams per tonne silver and 3.26 per cent copper (Assessment Report 18202). However, the mineralization was judged to be sporadic, and apparently decreases with depth and along strike.

Elsewhere on the property (Conductor "F") the sheared contact (striking 150 degrees) between a feldspar porphyry dyke and silicified monzonite is marked by strong sulphide mineralization. A select grab sample from here assayed 126 grams per tonne gold and over 1 per cent copper, and a 2-metre channel sample averaged 85 grams per tonne gold and 51 grams per tonne silver, and over 1 per cent copper (Assessment Report 18202).

Bibliography
EMPR AR 1966-55
EMPR ASS RPT *8744, *18202
EMPR EXPL 1980-278; 2002-29-40
GSC OF 1163
GCNL #245, 1980; #66(Apr.7), 1997
PR REL Saxony Explorations Ltd., Dec.18, 2002

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