The Ophir Project consists of one tenement (EL8323) of around 174 km². It is located around 15 km northeast of Orange. Ophir is famous for being the location of Australia’s first recorded gold rush. There are also several other workings in addition to the Ophir gold workings within the tenement.
The geology consists of Ordovician mafic volcanics, volcaniclastics and intrusions, Silurian-Early Devonian intermediate to felsic volcanics and volcaniclastics and Carboniferous felsic intrusions. The area appears to have a complex structural history with folding and thrust faulting present.
Only minor modern exploration activities have been carried out on the tenement, with stream sediment sampling being the most comprehensive.
This project is prospective for a variety of deposit styles including; porphyry hosted gold-copper, VHMS, orogenic gold and base metals.
The Ophir Project has a rich history of gold mining, with the first payable gold workings commencing in 1851. These workings are considered to be the first payable goldfield in Australia. Mining included hard rock, alluvial and deep lead mining. It is reported that small scale deep lead mining is still occurring or has only recently ceased (Vassallo J. , 2019b). Historical location names for workings included; Ophir, Dead Horse Gully, Summerhill Creek and Pine Forest. These are all recorded as being gold occurrences. This is one noted occurrence of copper workings (MinView, 2019) within the tenement, located approximately 4.5 km east of the Lewis Ponds workings.
The area contains the Early Devonian deep marine and volcanic rocks of the Hill End Trough, and rocks of the Early to Late Silurian period including the Mullions Range Volcanics, the Barnby Hill Shale and the Anson Formation. The far northern part of the tenement contains the Oakdale Formation, which is within the Molong Volcanic Arc. There are also recordings of small Carboniferous granitic intrusions and capping by Tertiary basalts.
The area is structurally complex, especially the southern and central portions of the tenement, with major structures dominated by east over west thrusts and associated folding. Major faults such as the north-northwest trending McDonalds Hill, Lewis Ponds, and Godolphin Faults, which have been interpreted as east dipping low-angle thrust faults, are present in the southern and central section of the tenement. A seismic line conducted in 1992) which runs across the tenement and directly through the Dead Horse Creek historical workings, shows these low angle thrusts.
The tenement is prospective for orogenic gold deposits, similar to the hard rock shear and vein hosted deposits historically mined at Ophir, placer/alluvial and VHMS style mineralisation.
There are no recorded Mineral Resources located within this tenement.
The historical workings at Ophir extending over an area of approximately 4 km × 2 km, combined with significant interpreted structures indicates the economic potential of this area.
Outside of the Ophir mining centre, VHMS deposits have the potential to exist due to the presence of lithologies (Mumbil Shelf Formation) within the tenement that host deposits in other locations nearby. This includes Lewis Ponds and Mt Bulga (historical production of 6.5% Cu). The Drapers Creek and Belgravia prospects are also prospective for VHMS-type deposits. Both of these are within the same stratigraphic and structural setting from the Calula and Larras Lake workings, located approximately 7 km to the north in the Copper Hill East tenure.
Although there is limited recorded outcrop of granitic intrusions, there is still the opportunity for porphyry-style gold-copper mineralisation being present.
Lower Lewis Ponds is along strike and in the same structural setting i.e. hanging wall of the Lewis Ponds Fault, as the main Lewis Ponds deposit, however previous exploration has been at a very low level and similar to some of the other prospects in this tenement, require follow-up work.
Alluvial/placer deposits have been mined in the past; however, they are expected to be small and of low tonnages and hence in an exploration context, would be considered a low priority.
The main initial focus will be to finalise Native Title agreements around the Ophir prospect.