Dargues Gold Mine – Exploration
Exploration at Majors Creek
New South Wales
The Majors Creek Gold Project is located in the highly prospective Lachlan Fold Belt of the Southern Tablelands region of NSW. The town of Braidwood, 60km southeast of Canberra, is positioned in the centre of the 659 sqkm tenement package. The project area covers a significant portion of the Majors Creek (Elrington) goldfield, the Jembaicumbene alluvial goldfield and a portion of the Araluen alluvial goldfield. This area represents the largest alluvial goldfield in NSW, with gold production at the turn of last century of 1.25Moz.
During the 19th century high grade, structurally controlled, primary gold mineralisation was discovered and mined from a number of localities in the “roof zone” of the prospective I-type Braidwood Granodiorite. Dargues Reef, the principal exploration target, was mined from 1870-1891 and again from 1914-1916 reaching a maximum depth of 70m. The Dargues Reef represents only one of the potential sources of the regions extensive alluvial gold occurrences. The Majors Creek area contains at least 24 other historic hard rock mines, including Snobs, United Miners, Dunsheas, Big Hill, Rise & Shine and Camages, all which have verified historic head grades ranging from ¼ to 4ozs.
The Majors Creek Project has been actively explored since its acquisition by Cortona in 2006; exploration activities include regional geological mapping, rock chip sampling programs, +40,000m of RC and diamond drilling, extensive soil geochemistry programs as well as compilation of comprehensive geophysical surveys such as heli-magnetic, gravity, induced polarisation and remote sensing imagery.
Mineralisation, occurs in quartz veins in the form of free gold, or associated with altered quartz-sericite-calcite-pyrite felsic and phyllic lodes and occasional quartz/calcite veining. Gold is frequently associated with pyrite and chalcopyrite with higher grade mineralisation often restricted to discrete ore shoots, true widths range between 5 and 15 metres, surrounded by a large medium grade mineralised envelope. Drilled intercepts include contained sectional grades of up to 25g/t Au over the widths of up to 3m. Interpretation of the geological data indicates an extensive multi-lode ore system ranging from 3m to 20m in width comprising high-grade gold bearing ore shoots that remain open at depth (+500m).
Gold mineralisation at Dargues Reef occurs in the footwall and the hanging wall as a steeply dipping, fracture controlled lode systems within zones of intense alteration in the host Braidwood Granodiorite. The lodes follow a well-developed fracture system adjacent to an intrusive dolerite dyke. At Dargues, the two main lodes thicken where they intersect creating a broad steep easterly plunging ore shoot. Several smaller sub-parallel lodes have also been intersected in the adjacent wall rocks (4m @ 28g/t Au from 103m & 1m @ 13.5g/t Au from 110m in DREX140).
The Measured, Indicated and Inferred resource (JORC compliant) at Dargues Reef is currently
1,615,000t @ 6.3g/t Au for 327,300oz Au (<2g/t cut-off).
The ore body remains open at depth (+450m), as indicate by some of the deepest holes drilled to date:
- 5.7m @ 97.13 g/t Au from 454m in DREX226 (open at depth)
- 9.9m @ 32.2 g/t Au from 511.3m (DREX225W2) (open at depth)
- 8.2m @ 5.2 g/t Au from 556.6m in DREX083 (Approximately 50m below the mineable resource)
The known mineralisation extends east of Dargues and on into the adjoining Plums and Chianti prospects, a strike distance of +500 metres. Plums (drilled to 250m) and Chianti remain open and untested at depth, the possibility of a Dargues like ore body duplication at both these prospects, along strike, of Dargues, presents as a possibility. Drilling of Plums Lode, east of Main Lode on the Dargues Reef line, has discovered a highly anomalous zone that may represent a structural duplication of the high-grade Main Lode.
The Majors Creek area presents numerous exploration targets within a 2-3km radius of Dargues such as Plums, Chianti, Dreadnought, Thompsons, Copper Ridge, Excalibur and numerous historic underground workings in a relatively unexplored historic goldfield. Cortona have recently initiated near mine exploration campaigns aimed at complementing the Dargues resource with near mine shallow resources such as the Ruby Lode, Scarlet and Chinaman’s Prospects. Recent drilling at the Hughen Prospect (500m north of Dargues) returned an outstanding silver intercept of 1m @ 687 g/t Ag (22oz) from 49m with associated anomalous copper (0.22%) and lead (1.81%).
Further regional exploration is planned with the objective of discovering a pipeline of satellite production opportunities in the immediate Dargues area and beyond. The extensive tenement holding (659 sq km) is viewed as highly prospective and several new exploration targets, such as Napoleon, have been discovered in highly altered rocks of the northern tenements.