The Belara Project (EL9184, ELA6176 and ELA6287) is located 100 km north-northeast of Orange in Central NSW (Figure 1). Access to the Project is via the Gulgong-Wellington road, with the Belara and Native Bee historic underground mines located approximately 5 km west of Goolma. The land has a maximum relief of approximately 715 m and the topography becomes more varied towards the east of the Project Area. The land is used extensively for grazing and cultivation.
The main target in the project area is on the prospective trend for known VAMS mineralisation that was mined at the Belara and Native Bee underground mines in the 1800s and has been explored from the 1960s until the present day. This is a significant development opportunity that has the potential to deliver a JORC 2012 compliant resource in a short time frame using modern exploration techniques to acquire the required data to support the historic exploration results to date.
Figure 3. VAMS mineral potential map over the project area. Warmer colours represent higher geological potential for VAMS-type mineralisation.
The prospectivity of the region around the Belara mine area for hosting additional VAMS massive sulphide mineralisation, which tends to form clusters of deposits, has been confirmed by mineral potential modelling by Kenex for the NSW Geological Survey. https://search.geoscience.nsw.gov.au/product/9253; Figure 3).
The mineral potential maps produced for orogenic Au and skarn mineral systems also highlighted prospective ground in the east of the Project Area, which was the basis for the application for ELA6287, which covers the Gulgong area where alluvial gold has been mined in the past.
Regional Geology and Mineralisation
The Belara project area is located at the northern end of the Hill End Trough in the eastern Lachlan Orogen in central New South Wales (Figure 4). Most of the base metal mineralisation in this part of the Hill End Trough is associated with the Upper Silurian to Lower Devonian sedimentary units. The mineralisation has historically been interpreted to be Kuroko-type VAMS style mineralisation. These deposits are strata-bound accumulations of sulphide minerals that precipitated at or near the sea floor in spatial, temporal, and genetic association with contemporaneous volcanism and syn-volcanic faulting. Massive sulphides are typically dominated by pyrite with lesser (though variable) sphalerite, galena, and chalcopyrite, and minor tetrahedrite–tennantite, arsenopyrite and pyrrhotite. However, pyrrhotite can be a major sulphide in deposits close to the volcanic centre/subvolcanic intrusion. In addition, barite is often present.
Figure 4. Regional geological setting of the Belara Project area within the Eastern Lachlan Fold Belt
Major deposits include Woodlawn and Captains Flat, both in the Goulburn Basin, and Commonwealth, Galwadgerie, Lewis Ponds, and John Fardy in the Hill End Trough.
Both Woodlawn and Lewis Ponds have lens-, replacement-, and stringer zone-styles of mineralisation. For example, the lower horizon at Woodlawn has a classic asymmetric morphology with a stratiform zinc–lead-rich massive sulphide lens overlying and interfingered with copper-rich massive sulphides with a copper-rich stockwork or stringer zone.
VAMS mineral deposits that have been mined and explored in the eastern Lachlan Orogen, similar to the Belara and Native Bee mines, are listed in Table below. Belara is listed with other deposits in the NSW base metal asset list https://resourcesandgeoscience.nsw.gov.au/__data/assets/pdf_file/0005/541463/lead-zinc.pdf
VAMS mineral systems within the eastern Lachlan Orogen as reported in NSW government MetIndEx database).
Local Geology and Mineralisation
Figure 5. Basement geology and mapped faults (yellow = Crudine Group; pale blue = Chesleigh Group; red = monzodiorite intrusions), also showing location of known mineral occurrences in the district. Data from Geological Survey of NSW (1:100,000 scale).
The geology of the project area is dominated by volcanic and quartzose sandstone of the Chesleigh Group and volcanic and deep marine sandstones of the Crudine Group (Figure 5), which were deposited in the Early Devonian. Several narrow Devonian monzodiorite intrusions occur mostly within the Chesleigh Group rocks (Figure 5). The Belara Mine occurs within a sequence of Silurian quartz-muscovite-albite phyllites and schists that overlie dacitic volcanics near the top of the Chesleigh Formation. Within the phyllites, there are two coarse-grained marker horizons. The mineralisation that has been discovered to date occurs between these units, which can be mapped at a regional scale. More detailed description of the geology and structure of the Belara Project area is given in the Independent Geologists Report in Annexure A.
Base metal mineralisation was first discovered at the Belara and Native Bee mines pre-1875 and was worked intermittently until 1908. The copper ore at the Belara mine was primarily extracted from the supergene zone. During the life of the mine, about 260 tonnes of copper was extracted from 8,000 tonnes of ore. The width of the lodes varied from 0.5 to 3 m and average mining grades were 3-5% Cu, 2.0-4.5 g/t Au, and 2-3 oz Ag. Zinc and lead were not produced at this time. The workings at the Belara mine had a recorded maximum vertical depth of 60 m, with drives on three levels over at least 500 m, with stope production over 100 m. The underground levels have a dip of 75° to the east, and the strike is about 340° magnetic, parallel with both the cleavage and regional bedding. Approximately 25 tonnes of metallic copper was extracted from 500 tonnes of ore at the Native Bee mine. The lode at Native Bee was mined from 4 shafts over a length of 137 m, and to a depth of 27 m. The lode widths were reported to vary from 1-6 m.
Modern exploration since 1960 is described in detail in the Independent Geologists report in section 2.5. Better intersections from the historic drilling include (a more detailed description of the drilling results is given in the Independent Geologists Report in Annexure A; Figure 6):
Figure 6: Belara - Native Bee Long Section - looking west +/-100m. Historical drilling and Ironbark drilling showing significant intersections.
- Hole B024 intersected 4 m @ 0.7% Cu, 1.1% Pb, 3.7% Zn, and 39 g/t Ag from 81 m.
- Hole B026 has an initial 4 m intersection at the top of the hole @ 0.5% Cu, 0.3% Pb,3.5% Zn, and 4.2 g/t Ag, which is likely supergene enrichment. A second intersection of 1.5 m @ 2% Pb, 7% Zn, and 61 g/t Ag was also recorded from 132 m.
- Hole B027 intersected 1 m @ 1.6% Pb, 4.8% Zn, and 74 g/t Ag from 186.5 m
- Hole B028 intersected 2 m @ 111 g/t Ag and 5.3% Zn from 164.5 m; 1 m @ 3.4% Pb from 165 m; and 2 m @ 1.5% Cu from 165.5 m.
- Hole B029 intersected 2.5 m @ 60 g/t Ag and 5.1% Zn from 253.5 m, and 0.5 m @ 5.4% Pb from 255.5 m.
- Hole B030 intersected 8 m @ 0.6% Cu, 2.1% Pb, 4.6% Zn, 73 g/t Ag, and 0.54 g/t Au from 299 m.
Although as confirmed by the Geological Survey of NSW prospectivity modelling project there is good potential for new discoveries of VAMS mineralisation in the regional area, the remainder of the project area remains largely underexplored for base metal mineralisation. Particularly there has been no electrical geophysical surveys carried out at a local and regional scale, which would be expected to map potential extensions and repetitions of the known massive sulphide lodes mined historically. Historic drilling at Ben Buckley returned results including 1.2% Zn, 21.5% Pb and 0.6% Cu, further confirming the regional potential for new discoveries of VAMS base metal mineralisation.
Figure 7: Ironbark aeromagnetic survey over Belara and Native Bee. Image shows the TMI1VD map clearly showing a porphyry signature to the ENE of Belara Mine.
The proximity to the northern Molong Volcanic Belt, which forms part of the Macquarie Arc, suggests that the regional area may also have potential for hosting porphyry Cu-Au mineralisation like the recent Boda porphyry copper and gold discovery 15 kilometres to the east of the Belara tenement (EL6031). A review of a recent high-resolution geophysical survey undertaken in 2011 has a porphyry signature in the TMI 1st vertical derivative map approximately 1.1 km to the ENE of Belara Mine (Figure 7). There is no drilling over this area, and very little surface geochemistry. Two smaller porphyry signatures are also observed to the NE and NW of Belara (Figure 7). It is possible that there are previously unknown porphyries within ELA6032 that are like the Boda discovery that have not previously been mapped due to the lack of high-resolution geophysics over the area. This would need to be confirmed through both geochronology and whole rock geochemistry.
The Gulgong application (ELA6287) covers an area with known historic alluvial gold workings where gold can still be panned in the creeks. The source of the alluvial gold has not been found, which provides the opportunity for modern exploration techniques to be used to make a new gold discovery in a region with well-known gold mines like McPhillamys (3.0 million ounces of gold), Cowal (5.0 million ounces of gold) and Tomingley (0.6 million ounces of gold).