Geological Description

The Forest Hill Gold District is situated on the south limb of a generally east-west trending anticline which is overturned to the south. As a result, bedding dips steeply (65-76°) to the north as does the fold axis (Woodman, 2002). Although the location of the fold hinge was not positively located during exploration efforts, structural evidence suggest that the fold hinge plunges gently eastwards at 6-15° A west plunge on some minor folds and stuctures was also noted and this may indicate an undulating fold hinge or perhaps local deformation related to faulting. An axial planar cleavage, and a superimposed, subhorizontal, crenulation cleavage is evident and best observed within the schistose slate beds. The structural forces under which the crenulation cleavage developed is not well understood and may be related to later compression of the folds during granite emplacement. The stratigraphic package which hosts the veins has been traced along strike by diamond drilling for approximately 2km. The veins are mostly bedding-parallel and are confined to the schistose beds. Sixteen different Au-bearing veins were identified during underground exploration of the district.

Aero magnetic data suggests the district is highly strained and structurally complex. Geological mapping confirmed the presence of several fault and shear zones in the immediate Forest Hill area which may have caused local disruption and rotation of local stratigraphy and pre-existing structure. Underground mapping also documents significant dip-slip displacement of stratigraphy along faults. Some of the granitic plutons within the Forest Hill region exhibit a pervasive internal shear fabric indicating their emplacement occurred either during, or prior to, the waning stages of the period of shearing.

Mineralization

The Au mineralization at Forest Hill is hosted in stratabound quartz veins intruding the

metasediments. Most Au-bearing veins in the district fall within this class and range in thickness from a few millimeters to, rarely, up to a meter. Veins are laterally and vertically persistent and can often be traced for hundreds of meters within some slate or schistose units. Generally, the veins follow bedding contacts Carbonate is present in some of the auriferous veins. As well, arsenopyrite and pyrite with lesser amounts of galena, chalcopyrite, pyrrhotite and sphalerite are often frequently present. Tourmaline, scheelite, stibnite, cassiterite and feldspars have all been reported to occur in some veins. The Au mineralization at Forest Hill consists of fine- to medium-grained, “nuggetty”, free gold within the quartz veins and disseminated flakes of gold adjacent to selvage zones near vein/wallrock contacts.  Gold flakes interleafed with sericite and biotite in the silicified wallrock immediately adjacent to the veins have been reported, Gold has also been observed in close spatial association with galena and arsenopyrite and thus, the presence of these sulphides may serve as visual pathfinder to zones of Au mineralization.

The Salmon River, Joe, Barrel, Hard and Ophir leads all occur adjacent to the hinge of the Forest Hill Anticline and have numerous schistose lithologies associated with them.  

Mining

Gold-bearing quartz boulders were first discovered at Forest Hill in 1895 with mining beginning shortly thereafter in 1895 (Malcolm, 1976). Mining continued intermittently until 1916 under 7 different operators. The next period of mining was from 1934 to 1957.

Seabright Resourcs and Westminer carried out underground exploration and development from 1985 to 1989. Westminer Canada Limited records indicate that for the last 3 months of development at Forest Hill, 7,265 tons of ore at an RMD grade of 9.46 g/ton gold were mined from the Schoolhouse Vein Zone. If correct, then 58,566 tons of ‘mineable’ ore at between 7.6 to 9.46 g/ton remain based on the June 1989 Westminer Canada resource estimate.

Historic mining operations in the Wine Harbour Gold District resulted in a total reported production of 25,102 oz of gold, the seventeenth largest in the province.

The last recorded exploration diamond drilling was in 2006.