Summary:
The known deposits within the Atlantic operation area are considered to be examples of turbidite-hosted, orogenic mesothermal gold deposits.
Strata of the Meguma Terrane in eastern mainland Nova Scotia include the basal greywacke-dominated Goldenville Group and the overlying, finer-grained, argillitedominated Halifax Group. Cochrane Hill is hosted in the basal Goldenville Group.
The Beaver Dam deposit is hosted in the southern limb of a north-dipping overturned anticlinal fold. The Moose River Formation is relatively thick in the vicinity of the Beaver Dam deposit.
Structure
The host stratigraphy is offset into segments by two northwest-trending faults; the sinistral Mud Lake Fault and the dextral Cameron Flowage Fault. The Mud Lake Fault truncates, and forms the eastern boundary to, the Main Zone mineralization.
Metamorphism
Lithologies at Beaver Dam have been metamorphosed to amphibolite facies (biotite grade) increasing to higher (staurolite) grade with proximity to the River Lake Pluton, the contact of which is about 2 km west of the Beaver Dam deposit.
Mineralization
Gold mineralization at Beaver Dam has been recognised over a strike length of approximately 1.4 km, extending from the Main Zone northwest to the Mill Shaft Zone. Historical drilling has shown that mineralization weakens between the Main Zone and Mill Shaft Zone. The eastern end of the main zone is controlled by the Mud Lake Fault and possible offsets to the mineralization have been identified between the Mud Lake and Cameron Flowage faults and in the Northeast Zone, immediately east of the Cameron Flowage Fault.
The mineralised zone can reach as much as 100 m in width with better gold grade (e.g., >0.5 g/t) material typically confined to a 5–40 m width or widths within that zone. Mineralization has been identified in historical drill holes at vertical depths of >600 m below surface, and remains open below that depth.
Gold mineralization is hosted within quartz veins and within the argillite and greywacke host rocks. Mineralized quartz veins are typically 0.5–20 cm in thickness, are commonly bedding parallel, but can also include cross-cutting veins. Sulphide assemblages include pyrrhotite, pyrite and/or arsenopyrite with lesser chalcopyrite, galena or sphalerite. Gold commonly occurs within quartz veins as coarse (>1 mm) grains and clusters of finer, but still visible (<1 mm), grains. Coarse gold grains are more likely to be found at vein-wall rock contacts and are often spatially associated with sulphides.
In the immediate vicinity of the deposit the host stratigraphy has been subdivided into several mappable units, from oldest to youngest: the Crouse Mudstone, Hanging Wall Greywacke, Papke Mudstone, Millet Seed Sandstone and Austen Mudstone. The mineralized zone appears to gently cross-cut this macro-stratigraphy. Gold mineralization is often associated with sulphides including pyrrhotite, pyrite, arsenopyrite, and chalcopyrite.