Majors Creek Project
The Majors Creek Gold Project (100% CRC) 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.
Last 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, Cortona’s principal exploration target, was mined from 1870-1891 and again from 1914-1916 reaching a maximum depth of 70m. The Dargues gold mine represents only one of the potential sources of the regions extensive alluvial gold occurrences. The Majors Creek area contains at least 24 historic hard rock mines, including Snobs, United Miners, Dunsheas, Big Hill, Rise & Shine and Camages, which have verified historic head grades ranging from ¼ to 4ozs.
The Majors Creek Project has been actively explored by Cortona since its acquisition in 2006; exploration activities include regional geological mapping, rock chip sampling programs, +30,000m 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 widths of >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 hangingwall 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 two dolerite dykes. 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 Indicated and Inferred resource (JORC compliant) at Dargues Reef is currently
1,444,000t @ 6.2g/t Au for 286,000oz Au (<2g/t cut-off).
The ore body remains open at depth (+500m), 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 (Approx 50m below the mineable resource)
Results of the Independent Scoping Study on the potential development of the Dargues Reef underground mine has returned positive results with initial production of 188,000 oz over 4.5 years with average production of 40-50,000 oz/year and cash operating costs of $450/oz with an estimated pre-tax profit of A$68.4M (at a gold price of 1,150/oz). The study concludes that the proposed development is technically and economically viable using a cut off grade of 3.5g/t, assuming 10% mining dilution and an average 95% gold recovery. The approvals process is well underway and the Definitive Feasibility Study will be completed by late 2010.
A recent raising of A$10M (January 2010) has allowed the company to up grade the reserves at Dargues with round the clock drilling, conduct environmental studies, complete metallurgical testwork, geotechnical studies and finalize site infrastructure and mine design. Encouraging drill results continue to define and expand the known mineralized envelope; a revised geological model and upgraded resource calculation is expected by mid-late 2010. Diamond drill and RC results at Dargues Reef include the following intersections:
• 24m @ 7.9g/t Au in DREX007 from 148m
• 70.2m @ 2.7g/t Au in DREX028 from 300m
• 13m @ 5.53g/t Au and 12m @ 6.27g/t Au in DREX040.
• 9m @ 6.63g/t Au and 4m @ 7.01g/t Au in DREX039.
• 16m @ 3.38g/t Au and 4m @ 7.04g/t Au in DREX038.
• 11m @ 7.2g/t Au in DREX085.
• 13m @ 8.33g/t Au in DREX043.
• 12.4m @ 16.40g/t Au in DREX221.
• 5.7m @ 97.1g/t Au in DREX226.
• 22m @ 5.74g/t Au DREX193.
• 17m @ 6.27g/t Au in DREX182.
• 9.9m @ 32.2 g/t (incl. 3m @ 101.3 g/t Au) in DREX225W2
• 19m @ 9.13 g/t Au in DREX206
• 8.9m @ 15.2 g/t and 11.3m @ 12.4 g/t and 5.3m @ 6.78 g/t and 8m @ 7.7 g/t Au in DREX225
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 in this adjacent zone has identified Dargues type alteration and gold mineralisation (20m @ 6g/t Au from 158m in DREX135 – Plums lode). The mineralisation identified at Plums is not included in the recent scoping study or the mine plan.
Recent 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 recent intercept at Plums, 125m east of the Dargues resource envelope (DREX119) returned the following significant intersection:
28.7m @ 5.88g/t Au from 195.5m including 10.5m @ 8.17g/t Au and 11.2m @ 6.98g/t Au in DREX119.
This intercept highlights the potential to significantly increase the recently announced resource estimate. The latest results from Plums drilling include:
• 20m @ 5.99g/t Au from 158m (DREX135)
• 16m @ 4.66g/t Au from 124m (DREX122)
The Dargues Reef gold deposit is still at a ’mid-late’ stage of appraisal and geological analysis remains ongoing. The deposit is shaping up to represent a substantial gold resource with grades, widths and near vertical orientation of the lodes that are eminently suitable to an underground mining operation. The final mine design is expected to be completed by mid-late 2010 following the DFS study and the upgraded new resource calculation.
Cortona are targeting a +500,000 oz gold resource at Dargues.
The Company has expanded exploration efforts to include the near mine zone - within 3km of Dargues Reef. Targets include IP generated anomalies such as Tulloch, Thompsons, Glencoe and Hughen; historic workings along the Snobs-United Miners line (1m @ 8.13 g/t Au from 107m in MCRC022 and 1m @ 7.70 g/t Au from 177m in MCRC028) and gold-in-soil anomalies such as Dreadnought (16m @ 1.12 g/t Au from 60m in MCRC014) as well as previously explored prospects such as Copper Ridge and Exeter Farm (19m @ 5.6 g/t Au from 47m in EXEX007).
Mining scoping studies commenced in 2008 with initial metallurgical test work on a typical mineralised section of Dargues Reef Main lode, testwork results returned outstanding (99%) gold recoveries. The scoping and feasibility evaluation process has been expanded to include more metallurgical studies, flow sheets analysis, design criteria, mining method, mining rate, infrastructure layout, power consumption, geotechnical studies, operating costs and environmental assessment.
Cortona now control unfettered access to all areas within the Dargues Mining Lease and immediate surrounds following the purchase of 319Ha of freehold farmland last year and more recently an additional adjoining 120Ha of freehold farmland was acquired. The land acquisition will allow greater flexibility for infrastructure planning and the ability to target the resource with precise rig positioning.
Recent drilling at Exeter Farm (2009), 2km north of Dargues, has confirmed a new discovery. Exeter displays a chargeability IP anomaly, several anomalous drill intercepts and an extensive mineralised alteration zone. Exeter Farm, originally drilled in 2008 at the Tory Boy prospect, returned a significant intersection from the first hole (EXEX007) drilled.
• 19m @ 5.6 g/t Au from 47m in EXEX007 incl. 2m @ 1.3% Cu plus 2m @ 5.0g/t Ag from 71m within a broader mineralized envelope of 37m @ 3.32g/t Au from 43m
Recent follow up RC drilling (Sept 2009) at Tory Boy has also returned several significant intersections from shallow depths including:
• 5m @ 4.88g/t Au from 76m in EXEX014
• 7m @ 4.07g/t Au from 25m and 6m @ 1.35g/t from surface in EXEX026
• 9m @ 5.2g/t Au from 51m in EXEX028
The identified gold mineralisation is within multiple strongly developed sulphide rich felsic lodes, akin to the alteration characteristics and mineralisation widths of Dargues. The newly discovered lode system remains open in all directions and will be evaluated further. Exploration at Exeter Farm is at an early stage however the discovery of a broad Dargues Reef style lode, close to the surface, is viewed as very encouraging.
The Majors Creek area presents numerous exploration targets within a 2-3km radius of Dargues such as Plums, Chianti, Dreadnought, Thompsons, Copper Ridge, Exeter Farm and numerous historic underground workings in a relatively unexplored historic goldfield. Cortona have initiated exploration campaigns “within the shadow of the headframe” aimed at complementing the Dargues resource with near mine exploration.
The company strategy is to fast track the development of a high quality gold operation at Dargues which will provide the cash flow to fund mine development and ongoing exploration. Regional exploration continues with the objective of discovering a pipeline of satellite production opportunities in the immediate Dargues area and beyond. The extensive tenement holding (659 km sq) is viewed as highly prospective and several new exploration targets have been discovered in highly altered rocks of the northern tenements.
Cortona is extremely positive with the exploration results received to date and believe that the emerging gold camp hosts numerous prospective areas that will, with further exploration, reveal considerable wealth to shareholders.
Drilling during the past year along the Dargues line of lode has returned numerous significant intersections including an outstanding 3.8m @ 143.6 g/t Au in DREX226.
• 16m @ 11.0g/t Au in DREX050.
• 5m @ 16.2g/t Au in DREX054.
• 10m @ 7.64g/t and 7m @ 7.25g/t Au in DREX059.
• 11m @ 6.85g/t Au in DREX067
• 14m @ 6.95g/t Au in DREX079
• 12m @ 6.80g/t Au in DREX071.
• 7m @ 6.44g/t Au and 5m @ 9.94g/t Au in DREX094.
• 14m @ 8.11g/t in DREX095.
• 7m @ 10g/t Au and 4m @ 10.8g/t Au and 3m @ 6.2g/t Au in DREX100.
• 17m @ 6.34g/t Au and 8m @ 3.40g/t Au in DREX106.
• 11.5m @ 8.19g/t Au and 12.2m @ 6.98g/t Au in DREX119
• 6.3m @ 7.30g/t Au in DREX122
• 16m @ 4.66g/t Au in DREX128
• 20m @ 5.99g/t Au in DREX135
• 4m @ 28g/t Au in DREX140
• 17m @ 7.44g/t Au in DREX166
• 5.7m @ 97.1 g/t (incl. 3.8m @ 143.6 g/t) and 2.8m @ 39.1 g/t and 5.5m @ 14.4 g/t Au in DREX226
• 19m @ 6.62g/t Au in DREX167
• 13.2m @ 10.9 g/t and 18.5m @ 4.9 g/t and 8.4m @ 4.5 g/t Au in DREX223
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