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File Created: 10-Jan-95 by Dorthe E. Jakobsen(DEJ)
Last Edit:  02-Dec-14 by Laura deGroot(LDG)

Summary Help Help

NMI
Name DAVID, LEW, HARMONY, ROB Mining Division Fort Steele
BCGS Map 082F040
Status Developed Prospect NTS Map 082F08E
Latitude 49º 21' 45" N UTM 11 (NAD 83)
Longitude 116º 08' 07" W Northing 5468114
Easting 562787
Commodities Gold, Copper, Lead, Zinc Deposit Types I05 : Polymetallic veins Ag-Pb-Zn+/-Au
I01 : Au-quartz veins
Tectonic Belt Omineca Terrane Ancestral North America
Capsule Geology

The David deposit is located about 30 kilometres southwest of Cranbrook. The showing was discovered in 1990 and work that year comprised prospecting, geologic mapping, soil geochemistry, trenching, geophysics and diamond drilling by Dragoon Resources Ltd.

The area is underlain by sedimentary rocks of the Aldridge Formation of the Middle Proterozoic Purcell Supergroup (Belt). These strata are folded in the core of the Purcell anticlinorium. The Aldridge Formation consists of a thick section of basinal turbidites overlain by quartzites and siltstones of the Creston Formation and siltstones and carbonates of the Kitchener Formation. The Aldridge Formation is intruded by gabbro to diorite sills also of Middle Proterozoic age. Cretaceous granodiorite and quartz monzonite intrusions cut these rocks. Faults occur in two main orientations: northeast striking, predominantly west dipping normal and reverse faults, and easterly striking transcurrent faults.

Locally, the area is underlain by fine grained clastic rocks of the Middle Aldridge and Lower Creston formations. Middle Aldridge lithologies are typically medium-bedded siltstones and quartzites to laminated silty argillites. Lower Creston lithologies exposed on the northwest side of the property are thin bedded and laminated argillites. Gabbro and diorite sills and dikes are present mainly in the Aldridge Formation. At least seven sills have been identified on the property; some of these appear to be related to mineralization. Structure is dominated by north-northeast oriented steeply west dipping normal and reverse faults and shear zones. The most prominent is the Baldy normal fault.

The discovery showing was an exposure of gold-mineralized quartz. Chip sampling across 40 centimetres assayed up to 144 grams per tonne gold (Property Development Report by Bapty Research Ltd., 1991).

Significant gold mineralization is restricted to shear zones, semiparallel to bedding in the hostrocks, or closely related quartz veins. Mineralization consists of pyrite, galena, chalcopyrite and sphalerite with some visible gold. Alteration consists mainly of silicification, with lesser chlorite and clay.

The David shear occurs within quartzites and siltstones of the Middle Aldridge Formation and has been traced along strike for 1600 metres and 150 metres downdip. The shear contains anomalous gold values over this entire length. The 0.20 to 1.5 metre wide shear strikes 010 degrees and dips 60 degrees west, cutting the bedding of the hostrocks at an oblique angle. The average gold content is 0.5 to 2.0 grams per tonne. Mineralized ancillary shears intersect the main shear.

Quartz veining is locally common throughout the quartzites and siltstones ranging from small irregular quartz sweats, through thin quartz-feldspar stringers to wider (greater than 20 centimetres) quartz veins. Wide quartz veins that occur in the shear zone often carry significant gold values and about half the noted visible gold occurrences have been in such veins.

The mesothermal gold mineralization is structurally and lithologically controlled and is believed to have been deposited from oxidizing fluids associated with Cretaceous felsic intrusions.

Drilling outlined one continuous zone of gold mineralization over a strike length of 150 metres and to a depth of more than 100 metres; thickness averages 2.35 metres. Inferred resources for this zone are 96,000 tonnes grading 13.08 grams per tonne gold (uncut) or 7.11 grams per tonne gold (cut) (Property Development Report by Bapty Research Ltd., 1991).

Bibliography
EM GEOS MAP 1998-3
EMPR ASS RPT 20365, 20873, 21504, 24244, 24263
EMPR MAP 49
EMPR OF 1994-8
EMPR PF (Prospectors Report 2001-28 by Peter Klewchuk)
GSC MAP 11-1960; 15-1957
GSC MEM 228; 292
GSC OF 820; 929; 2721
*Property Development Report by Bapty Research Ltd., 1991

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