Cobar Basin / Lachlan Fold Belt Projects (NSW)
Figure 2a: Alchemy projects, major mines, Au / Cu mineral occurrences, and major structures over aeromagnetic image
Overflow Gold-Base Metal Project (378km2)
The Overflow Gold-Base Metal Project consists of four exploration licences located over a 50km long section of the Gilmore Suture at the intersection of the Lachlan Transverse Fault Zone within the well-endowed Cobar Basin (Figure 2a). The project is highly prospective for epithermal, porphyry Cu-Au, and Cobar-style Au and base-metal mineralisation.
Mineralisation at the Overflow Prospect is structurally-controlled high-grade Au-Ag and base metal credits, with extensive down-plunge potential, typical of Cobar-style mineralisation.
*Gold equivalent (AuEq) values were assigned to each drilling intersection using the following formula (based on metal prices at the time): AuEq (g/t) = Au (g/t) + Ag*0.014 (g/t) + Cu*1.11 (%) + Zn*0.54 (%) + Pb*0.46 (%). The AuEq calculation takes into account the following metal prices: Au US$1325/oz, Ag US$19/oz, Cu US$2.15/lb, Zn US$1.05/lb and Pb US$0.90/lb.
A review of the historic drilling and 3D modelling of mineralisation at Overflow suggests the mineralisation dips steeply to the WSW, plunges to the south, is associated with distal chlorite-sericite and proximal silica alteration, and displays a significant metal zonation.
Metal distributions were modelled for AuEq, Au, Ag, Cu, Zn, Pb and sulphides with lithology. Total grade multiplied by thickness grade shells of AuEq values are illustrated as a long section through the deposit and suggest that several high-grade zones remain open down plunge or open down dip (Figure 3).
Figure 6: Yellow Mountain Project – Historic drilling maximum downhole copper over aeromagnetic image (left), and historic drilling maximum downhole gold over geology (right).
Eurow Copper-Gold Project (167km2)
The Eurow Copper-Gold Project (“Eurow”), located 30km southeast of Parkes (Fig. 2), covers meta-sediments and granite intrusives within the Lachlan Transverse Zone (Fig. 7). The Project area contains the historic Eurow-Vychan Cu-Au workings where drilling by previous companies returned high-grade intercepts including:
8m @ 2.95% Cu, 0.85g/t Au from 47m (Eu4)
5m @ 1.83% Cu,1.30g/t Au from 77m (Eu_H)
3m @ 3.99% Cu, 1.25g/t Au from 73m (Eu_D)
2.2m @ 4.65% Cu, 1.78g/t Au from 277.7m (EU027)
3m @ 5.32g/t Au, 0.21% Cu from 11m (Eu1)
3m @ 3.27g/t Au, 4.40% Cu from 89m (Eu_F)
A 3D view of the Eurow Mine drilling looking down to the NNW can be seen in Figure 8. The copper-gold mineralisation dips steeply to the west and appears to plunge to the south. Mineralisation remains open along strike to the north, south, down dip and down plunge. Further drill testing at this prospect is required.
Girilambone Copper Project (129km2)
The Girilambone Copper Project (“Girilambone”) is located 20km east of Aeris’ Tritton copper operation and along strike of the Murrawombie / Girilambone Copper Mine (Fig.2). The area is prospective for ‘Besshi-type’ volcanic massive sulfide (VMS) copper-gold mineralisation within mafic units of the Ordovician Girilambone Group. An historic exploration data compilation and evaluation is underway.