CORE SHACK Scotian Gold: The Beaver Dam Deposit

Beaver Dam, a gold-bearing quartz vein system within sedimentary rocks of the Meguma Group, 82 km north east of Halifax, N.S., contains proven and possible ore reserves of 2.7 million tonnes grading 9.3 g gold per tonne over a strike length of 600 m and to a depth of 600 m. The deposit is open along strike and to depth. Seabright Resources, the operator, owns 100% equity interest in the property subject to a sliding-scale net smelter return royalty based on the grade of ore mined. The royalty ranges from 0.6% to a maximum of 3% payable to Acadia Mineral Ventures.

Gold was first discovered at Beaver Dam in 1868. Work on the property continued sporadically with generally poor results. Seabright optioned the property in 1985 and earned a 51% interest from Acadia Mineral Ventures by spending $275,000 on exploration. Seabright then purchased the remaining 49% interest and the company has been drilling continuously since November, 1985. In August 1986, underground exploration began with a decline to recover a 4,000-tonne bulk sample to be sent to Seabright’s mill at Gay’s River, 65 km west of Beaver Dam.

The Beaver Dam deposit occurs within the Goldenville Formation of folded and metamorphosed rocks belonging to the Lower Paleozoic Meguma Group. The Goldenville Formation consists predominantly of greywacke and quartzite with a lesser amount of intercalated argillite.

The mineralization at Beaver Dam occurs in the southern overturned limb of a moderate-to-tightly- folded anticline which is disrupted by faults to the east and by the River Lake monzo-granite pluton to the west. The fold axes and strata strike 100 degrees and dip 75 degrees to the north on the southern limb in the area of the deposit.

Stratigraphy at the deposit, from south to north, is: the Crusher Lake greywacke; Austen argillite and gold zone (Austen zone); footwall “Millet Seed” greywacke; Papke argillite and gold zone (Papke zone); hanging wall greywacke; Crouse argillite; a thin discontinuous unit of greywacke and the No. 4 argillite; and the Mud Lake greywacke. The stratigraphy is terminated and shifted north, about 500 m, by the Mud Lake Fault. The sequence is about 120 m thick from the south of the Austen zone to the north of the Mud Lake Fault zone.

Gold occurs in and adjacent to a series of stratiform quartz veins interbedded with argillite and greywacke. The veins vary in thickness from a few millimetres to a few metres and are laterally and vertically continuous. The mineralization is hosted by two main interbedded vein systems, or “belts,” termed the Austen and Papke zones. The Austen zone consists of numerous, steep, northerly dipping veins in argillite with minor greywacke which collectively average 3-10 m in true thickness. The Papke zone is similar in vein morphology and thickness; however its host rock is a black graphitic argillite.

Gold occurs in its free state within quartz veins, usually along quartz grain boundaries and within grains of pyrrhotite and chalcopyrite. In general, where there is an increase in the chalcopyrite content, there is also an increase in gold content. Gold also occurs within sulphide-rich rock adjacent to the veins. Minor amounts of arsenopyrite and pyrite with lesser amounts of galena, chalcopyrite, pyrrhotite, sphalerite and stibnite are present in the veins in association with carbonate, scheelite and tourmaline as accessory minerals. Pyrite, pyrrhotite and arsenopyrite are the dominant sulphide minerals in the wall-rock.

Depth of overburden at the Beaver Dam property averages 5 m which has permitted the successful application of geophysical and geochemical surveying.

Feasibility studies are now underway. Seabright’s target for production start- up, at 400 tonnes per day, is summer, 1987.

At presstime a positive mine feasibility study by Kilborn Ltd. was released by Seabright. Pamela Phillips is a Toronto- based consulting geologist. She would like to thank senior project geologist David Duncan for the information and Joe Campbell and Jim Fortin for their assistance.

GEOGRAPHICAL LOCATION: Beaver Dam, Nova Scotia