Summary:
The Jaurdi Gold Project overlies a portion of the Bali Monzogranite immediately adjacent to the Jaurdi Hills-Dunnsville greenstone sequence, which in the south hosts the Jaurdi Hills mining centre and the Dunnsville mining centre towards the north. The Bali Monzogranite and Dunnsville Granodiorite/Doyle Dam Granodiorite to the north, together occupy the core of a gently north plunging anticline. M16/529 is located to the west of the anticlinal axis and immediately adjacent to the granite-greenstone contact.
The Bali Monzogranite is poorly exposed. The greenstone-granite contact is foliated where exposed. Shear zones developed locally within the adjacent greenstones, may continue within the granite. Gold mineralised palaeochannels are known in the Jaurdi Hills area, particularly to the west and south of the Jaurdi Hills mining centre.
Lost Dog
The Lost Dog tenements (M16/529, E16/469 & P16/2925 &2926), which make up the southern parts of the Jaurdi Gold Project, are located close to the western margin of the Bali Monzogranite immediately to the south east of the exposed Jaurdi Hills greenstone sequence. The tenements are entirely soil covered, with well-developed nodular carbonate increasing in intensity southwards towards an active contemporary drainage.
Recent drilling programs have revealed an extensive system of Au-bearing sand channels indicating that a major long-lived palaeo-alluvial system was present in the area. A typical profile consists of transported lateritic gravels overlying plastic clay zones, which in turn overly thick, water saturated silt and clay sequences with minor cobble layers. Drilling evidence suggests that younger, perched channels overly older channels, indicating that an anastomosing series of paleochannels are present over an east-west distance of at least 800 metres. Two horizons of mineralisation have been identified in the Western Arm with the shallower lode situated between 12 to 16 metres vertical depth, and the second horizon between 18 to 25 metres. The Eastern Arm has been identified by a system which has at least 850 metres strike (East – West orientated), is 175 metres wide and 8 metres deep; and appears open to the northeast and connects with the Western Arm.
Black Cat
The Black Cat tenements (M16/34 & M16/115) make up the northwestern parts of the Jaurdi Gold Project, with M16/34 hosting the abandoned Black Cat pit and remaining gold resources at Black Cat North and Black Cat South. These tenements cover predominantly mafic and ultramafic rocks to the immediate northwest of the Bali Monzogranite and exposure of these rock types is extensive, particularly in the central and northern parts of M16/34. M16/115 is completely covered by transported sediments associated with modern day and palaeo-drainages. In the Black Cat area the mafic-ultramafic sequence generally has a northwest-southeast trend with a number of shears and faults, which are sub-parallel to the regional stratigraphy. To the immediate east of the Jaurdi Hills mining centre and in the vicinity of Jaurdi Hill itself, the mafic-ultramafic sequence as a more northeast-southwest trend, where it bends around the Doyle Dam Granodiorite, located to the north. Gold mineralisation at the Jaurdi Hills mining centre is typically associated with narrow quartz-veined shears of various orientations and/or with sheared felsic porphyries/granitoids, again having various orientations. Both styles are hosted by mafic volcanics and to a lesser extent by ultramafic volcanics. The Black Cat gold mineralisation is one of the largest porphyry/granitoid-associated deposits within the Jaurdi Hills mining centre with a number of stacked southwesterly dipping, relatively flat-lying shears within the porphyry hosting the gold. A large porphyry/granitoid body intrudes weathered and fresh mafic volcanic rocks and is covered with approximately 15-25m of transported cover. The majority of the Black Cat gold resources are located within weathered porphyry/granitoid and sometimes the weathered mafic rocks (in situ regolith).
Primary mineralised domains at Black Cat (10 domains in total) extend over a 550 m strike length. Lode widths are highly variable and range from 0.5 m to 12 m. Supergene domains (two domains) extend 570 m in the northwest–southeast direction and 500 m in the northeast–southwest direction. The depth below surface to the upper limits of the MRE is approximately 10 m (405 mRL). The MRE extends 95 m to a lower limit of 105 m (310 mRL) below the surface.
Panther
The primary ore lode at the Panther deposit is striking NW-SE, varyingly steep dipping 70°W shear zone, with a large scaled quartz vein stockwork associated with the gold mineralisation. A weathered profile exposed in Panther pit shows an upper saprolite and lower saprolite lithology suite including a high-magnesium basalt or ultramafic pyroxenite (multi-element to confirm) in proximity to basalt host rock.
The quartz veining stockwork is made up of vein sets regularly spaced approximately 5m apart, with horizontal and vertical sets ranging in thickness from 5cm to 40cm. The majority of mapped veins in the Panther pit are of 20-25cm thick on the footwallside of the shear and in proximity to the main NW-SE shear zone. The quartz veins deeper in pit are of increasing thickness, up to 40cm. Two other notable but smaller shear zones intersect the main shear zone entering from the west side of Panther pit.
A flat lying supergene enrichment zone is interpreted for both Northern and Southern extremities, where the Panther shear extends to surface. The supergene mineralisation varies in thickness between 1 and 6m.
MacPhersons Project
The MacPhersons tenements encompass the Hampton ultramafic sequence on the southern limb of the Tindal’s anticline and is bound by the Lindsay’s Basalt to the West and Gleeson’s Basalt to the East. The Hampton Ultramafic sequence hosts several historic mines including Surprise, Barbara, Shirl, 28 Pit, Noble 5. The main MacPhersons Reward and A-Cap deposits are hosted within an intrusive Tonalite along the western Mafic- Ultramafic contact. Gold mineralisation at the MacPhersons, A-Cap and Tycho projects have been delineated by a significant amount of drilling, and to a lesser extent, Pumphreys, Queenslander, Bakers and Franks Find.
A summary of the domains for each deposit is outlined as follows:
• MacPherson/A-cap - A total of 31 mineralised domains were interpreted, striking NW-SE and shallow dipping to the NW (~35o). The interpretation extends over a narrow strike length of 120 m, limited to the lateral strike extents within the main tonalite dyke intrusive. There is an extensive down-dip projection for the dominant domains of up to 1.1 km, with a maximum vertical depth currently at 370 m below the surface. The average true thickness varies between 5 m to 15 m. There is a significant supergene enrichment zone at MacPhersons averaging at 25 m to 30 m below the surface and corresponding to the bottom of the deepest pit mined today.
• Tycho – A total of 10 mineralisation domains have been interpreted trending NW to SE and dipping approximately 20o to the NE. The strike extent modelled to date is 350 m, and currently modelled to a vertical depth of 250 m below surface. Domains are relatively broad compared to MacPherson, averaging between 10 m to 20 m true thicknesses.
Geko project
Mineralisation at the Geko project is orogenic, structurally controlled gold mineralisation with a supergene overprint. The deposit is approximately 50 m wide with a strike length of 500 m. Gold mineralisation is present in mafic schists and ultramafic host rocks, with an upper weathered zone of saprolite and mottled laterite mineralisation. The weathered saprolite and laterite mineralisation is overlain by a mineralised paleochannel. The paleochannel is the shallowest mineralised unit of the deposit and is approximately 15–20 m below ground level.