The Ruby silver project (EL7711) is located approximately 30km east of Armidale in north-eastern New South Wales. The exploration licence covers roughly 60km2 and encompasses most of the Rockvale Adamellite, of the late Permian to early Triassic, which hosts zonally arranged arsenic-silver-gold mineralisation at its periphery and along northeast/ northwest orientated fracture zones within an intrusion of late Permian sediments. Three major known deposits are situated in the area; the Ruby and Tulloch silver mines and the Rockvale arsenic mine, along with numerous additional workings and prospects for silver and gold.
The Ruby silver mine is spatially associated with an aplite dyke traceable along a north-easterly trend for 650m. The lode is approximately 1.4m wide with a sub-vertical dip, and comprises of a complex sulphide assemblage with minor gold in a gangue of vein quartz and calcite with sericite-silica altered country rock. Between 1895 and 1900, the mine was worked to a depth of 120m for a yield of 350,000 oz silver at 620 g/ton. A drilling program conducted by Silver Valley Minerals in 1968 produced significant results, including 5.08m @ 216 oz/ton Ag and 1.42m @ 687.5 oz/ton Ag. Results from an IP survey conducted in 1969 have also suggested that sulphide mineralisation extends well beyond the single known silver-rich shoot, which presents further significant future drill targets.
On trend with and 2.5km northeast of the Ruby Mine, lies the Rockvale Arsenic Mine. Discovered in 1923, it has produced about 3,000 tonnes of ore containing 600 tonnes of white arsenic (arsenic trioxide) and is associated with altered aplite along with a north-east trending shear zone over a 1.5km strike. This shear intersects the contact between the Rockvale Adamellite and the Permian sediments to the northeast of the mine. Mapping has demonstrated that the mineralised structure and associated alteration persists over a strike length of at least 1120m. The lode comprises fine-grained, strongly ferruginous and locally scorodite-rich, seriticised quartzo-feldspathic rock with a strong foliation.
The Tulloch Mine, discovered in 1913, has produced an estimated 50,000 oz of silver, representing a grade of about 200 oz/ton. The northeast-trending lode from which bulk production was derived has a maximum width of almost 1m. Silver mineralisation at the mine is developed in fissures associated with three obliquely intersecting sets of shears near the contact of fine-grained sediments with the Late Permian-Early Triassic Rockvale Adamellite. Primary mineralisation is dominated by arsenopyrite, pyrite, sphalerite and galena in a quartz-calcite gangue.
Work to date
In April/May 2011, Peel Mining undertook an 18 line kilometre IP survey over the historic Tulloch silver mine and Rockvale arsenic mine areas; multiple zones of strong shallow chargeable anomalism have been identified, many of which are coincident or proximal to the known historic workings. These chargeable IP responses are interpreted as areas of concentrated sulphide mineralisation.
A preliminary RC drilling programme was undertaken in May 2012 at Ruby Silver comprising 15 holes for 1,483m; drilling was designed to test the IP chargeability anomalies, and also test beneath historic workings at the Rockvale and Tulloch mines. Several narrow, high-grade silver intercepts were recorded, with better results at the Tulloch Lode including 2m @ 32 g/t Ag from 9m, 3m @ 227 g/t Ag from 20m and 3m @ 267 g/t Ag, 0.82% Pb, 0.39% Zn from 115m in PRRC009. High-grade mineralisation was also intersected below the old workings, along with encouraging results from the near surface in a previously unidentified parallel lode.