Victoria Bore Copper Project
Victoria Bore Project contains a granted exploration licence (E08/3220) and one exploration licence application (E08/3326) centred on the historic Victoria Copper mine which, according to historic mining records, produced high Cu grades averaging 32.7% for 62.5 t of Copper from near surface in the 1950’s. The Victoria Bore Project is located approximately 120 km south of the coast town of Onslow and 130km south east of Exmouth in Western Australia. The tenements lie adjacent to the North West Coastal highway and are readily accessible by gravel tracks. The local roads, while requiring upgrade to support mining operations, are accessible year-round and suitable to support ongoing exploration teams and associated equipment including drill rigs during the drilling season, which is determined by climate including cyclones and extreme heat.
While no major mining has been undertaken, the small-scale historical Victoria Copper Mine mineralisation was discovered around 1914 with workings covering a length of 130 metres via a series of shallow shafts, 1-2 metres wide, with the main shaft to a depth of 21 metres with three drives.
Limited exploration has occurred within the tenements with no systematic exploration ever undertaken. In 2012 Auricup contracted Khumsup Ltd to conduct a MLEM survey over a 1 km strike length of the mineralised structure centred on the mine workings designed to identify potential strike and depth extension to the existing mineralisation. The survey identified two shallow; relatively strong late time conductors, possibly associated with mineralisation. The northern most conductor (T1) is at least 400 metres long and remains open to the north, though given the length of the conductor it most likely has a stratigraphic source. The second conductor (T2) is a discrete, short strike length conductor located to the south of T1 and closer to the historic workings.
Recent spoil dump samples show consistency with the documented grades from mining with samples ranging from 6.8% up to 49% Cu. The oxide zone copper species (carbonates, silicates and oxides) mainly occurred as infill in brecciated quartz veining whereas the chalcocite was mainly found as massive zones with accessory oxide zone phases. No primary copper sulphides were identified in the mine spoil which is consistent with the documentation that the mine working never intersected fresh rock. The highest copper values were associated with the chalcocite-rich transitional samples (28.3 – 48.6% Cu) however material amounts of Ag, Au and Bi can be observed.
The Project is at a very early stage of geological understanding with good exploration potential in both the short and medium term. A follow up drilling program along with systematic exploration methods will be applied in a phased exploration program. The limited exploration and production to date has focused on the near surface oxide material within the vicinity of the main shaft with no exploration testing the depth or strike extensions of the mineralisation.
Geology and mineralisation
The region surrounding the Victoria Bore Project tenements contains extensive outcrops of Lower Proterozoic metasediments which are unconformably overlain to the west of the tenement by siliclastics and dolomitic sediments of the Middle Proterozoic Uaroo Group. The Lower Proterozoic metasediments, comprising quartz wacke, rudite, pelitic schist, BIF, dolomite and quartz-arenites are thought to be equivalent to Wyloo Group sediments that occur further to the east. However, the overlying Uaroo Group, consisting of dolomites, arenites, shale, chert and minor conglomerate only correlates in part with the Bangemall Group and the similarly aged Padbury Group. Thus, the Uaroo Group may have developed in a local basin during folding and uplift of the Wyloo Group. All of the Proterozoic rocks have undergone low-medium grade metamorphism, although only the Lower Proterozoic metasediments and the bottom section of the Uaroo Group show a slaty cleavage and mineral lineation (at times a spaced cleavage) that is reported to have developed during a single deformation.
The regional area is dominated by north-northwest striking ridges of Lower Proterozoic metasediments which dip shallowly to steeply east. On the western side of the region, Uaroo Group sediments (steeply dipping west) crop out on the eastern limb of a large north-northwest trending open synclinal structure. This structure has straight limbs in the southern part and large-scale chevron folding in the north. Five kilometres west of the tenement area, a large north-south block (10 km long by 2 km wide) of dolerite intrudes the Uaroo Group Sediments in the core of the syncline. The stratigraphy has been dissected by many small creeks and the northward flowing Rouse Creek. Away from the ridges are spinifex covered sandy alluvial plains as can be observed in Figure 2-1 which overlay the tenement area.
The local region surrounding the tenement is dominated by the Archaean and early Proterozoic greenschist to upper-amphibolite facies crystalline rocks of the Gascoyne Complex that are unconformably overlain by an outlier of mid-Proterozoic greenschist to lower-amphibolite facies metasediments that comprise the Uaroo Group, as noted above. The Uaroo Group represents the western most part of the Edmund Supergroup that forms part of the Bangemall Basin. The pre-Cambrian basement is overlain to the west by the early-Cretaceous sediments of the Carnarvon Basin. Unconsolidated Quaternary cover is common across the area. The Victoria Bore Project is hosted within the Uaroo Group metasediments that form a tightly folded synclinal keel over the Gascoyne Group which is described above.
Within the tenements the Uaroo Group metasediments form the north-northwest trending limb of an open synform. Around the existing workings the lithology is defined by chloritic shales and infrequent platy quartzite, with numerous dolerite dykes intruding. The outcrop areas are generally comprised of quartz-chlorite and quartz-biotite schists with minor recrystallised carbonate beds also present.
Mineralisation at the Victoria Bore Project is interpreted to be structurally hosted and occurs within chlorite, dolomite and silica altered host rocks. Mineralisation is present as supergene chalcocite and chrysocolla and malachite-rich oxide mineralisation and is primarily associated with magnetite rich quartz-sericite/quartz-chlorite schists. Supergene chalcocite has been identified in hand specimen with primary (sulphide) mineralisation consisting of chalcopyrite, galena and sphalerite hosted by a carbonate unit. In the southern most prospective digging the occurrence of copper is associated with quartz veining.