Mt Barrow EL 6416

EL 6416 covers an area of 141 square kilometre and lies 50 km southeast of Cobar and is connected to Sydney via the Mitchell and Barrier Highways. A well formed road runs from Hermidale. The EL partially straddles the Gilmore Suture and covers a number of previously worked mines and several untested magnetic and geochemical anomalies. Some of the prospects on the EL share similarities with the Overflow Au-base metal mine to the south and the Mt Boppy Gold Mine to the north, which are also within the influence of the Gilmore Suture, a structure closely associated with gold and base metal mineralisation. The principal targets are Au/base metal mineralisation on the contact of Girilambone Beds/ Baledmund Fm, the Mt. Boppy style quartz-breccia lodes, and the Cu/pyrite/magnetite/quartz lodes such as occur at Girilambone/Tottenham/Canbelego South.

The Cobar area has yielded two of the largest individual gold mines in NSW, New Occidental near Cobar and Mt Boppy near Canbelego, and is the State’s main copper producing field (C.S.A., Great Cobar) and has the State’s largest reserves of Pb-Zn mineralisation outside Broken Hill.

The EL is 27 km south of the Mt Boppy Mine, which previously produced half a million ounces at 12.0 g/t Au (+Pb, Zn) from an epithermal vein system.

Base metal and gold workings covered by the EL share similarities with the Overflow Au-base metal mine to the south and the Mt Boppy Gold Mine to the north, previously the No.2 gold producer in NSW. The EL is also close to a number of interesting discoveries; the Hera Project, the Good Friday Prospect, and the Burra Copper Prospect.

The geology comprises Cobar Supergroup/Girilambone Beds, which are close to the eastern margin of the Cobar Basin on the western sector of the Lachlan Fold Belt the State’s main copper producing field (C.S.A., Great Cobar). The EL partially straddles the Gilmore Suture and contains a number of previously worked gold and base metal mines and prospects, including a cluster associated with ring fracturing and volcanics. Some untested magnetic and geochemical anomalies are present and a probable eruption centre has been identified. The EL has similar geology, structure and mineralisation to the Pooraka EL and the mineralisation appears to share geological similarities with Mt Boppy, 35 km to the north.

The EL is close to a number of interesting discoveries. About 20 km to the south of the EL, in similar geology but not directly along strike is the Hera Project, with Indicated and Inferred Resources of around 9 Mt @ 6.7 g/t Au, 14 g/t Ag, 0.2% Cu, 2.5% Pb, 2.8% Zn. The host rocks are fine grained sediments and dacitic volcanics in which quartz/sulphide veining is common. To the west of the EL is the Good Friday Prospect of Restdown Goldfield with a drill intersection of 23 m @ 23.9 g/t Au while to the north is the Burra Copper Prospect with 12 m @1.9% Cu and 2m @ 6.8% Cu, 0.4 g/t Au, 14 g/t Ag.

Principal old workings in the area include:

• The Glengarry Gossan; which extends over 140 m and returned anomalous Ag, Cu, Pb, Zn. The area was tested in 1975 with auger geochemistry, IP, and diamond drilling. They located one 2.6 m intersection of 10-15% massive sulphides, principally pyrite.
• The Herald Mine; is a 1-1.5 m quartz vein in dacite and feldspar porphyry. It was originally tested by underground workings to a depth of 25 m, with grab samples of quartz giving values to 9.6 g/t Au and 0.8% Pb.
• The New Era; A quartz shear originally tested by underground workings to a depth of 12 m. Gold and basemetal values were weakly anomalous.
• Rankins Prospect; a skarn with anomalous Cu, Pb, Zn, Ni and Co.
• The Victory originally tested by underground workings to a depth of 10 m in quartz veined volcanic.
• Bradburys Show; A base metal prospect tested by a shaft. An earlier explorer mapped the area in 1965 and Mines Exploration sampled the area and ran some ground magnetics in 1974 and again in the early 1980s. The gossan returned values to 1.2% Cu and 2.5% Pb. The workings are in Girilambone Formation close to the faulted Devonian (Barrow Range Syncline) contact.
• Other mines and prospects located within and on the edge of a probable major eruption centre associated with siliceous volcanics and tuffs.