The Copper Duke project consists of 11 mineral concessions covering a number of gold and copper porphyry occurrences in an area of approximately 100 sq. km. The project is located in Catacocha (Paltas) county, Province of Loja, approximately 18 kilometers east of the Company’s Dynasty Goldfield mining unit and 40 kilometers south of the Company’s Portovelo processing plant.
Figure 1 Above: Copper Duke Overview
To date, a major copper-gold porphyry complex, El Huato, and an additional four porphyry copper systems (Loma Redonda, Rio Catamayo, Landalima and Barbasco) and two gold targets have been identified. The Phase 1 exploration program will focus on El Huato and will seek to test both the project’s gold-copper porphyry potential and epithermal vein systems. A further overview of the Copper Duke area follows.
The El Huato copper-gold porphyry complex was discovered by a United Nations survey in 1968. It comprises volcano-sedimentary rocks overlying other intrusives. Sub-vertical to sub-horizontal veining and stockworks follow the stratification of these sediments striking southwest and southeast for a known length of 3.5 km.
The complex comprises a central high-grade gold porphyry and a southern high-grade copper-gold porphyry. There are also indications of high-grade copper and gold to the north of the area. In 1978, Adaro, a Spanish government company, drilled two holes into what was then considered the central gold porphyry that returned, respectively, 62.75 metres grading 1.73 g/t gold and 44.7 metres of 2.23 g/t gold. These historical drill holes are non 43-101 compliant. Core Gold management believes that these historical drill holes are effectively about 800m from what later surface sampling and geophysics define as the main El Huato target which will be tested in the Phase 1 drill program.
In its October 6, 2006 news release, the Company reported significant assays from 481 rock chip channel samples taken from epithermal vein swarms and stockworks located in an 8.5 sq. km area in the central sector of the Huato area. Results indicated the presence of widespread high-grade gold mineralization, ranging from 174 grams per tonne (“g/t”) gold to 0.1 g/t gold and from 249 g/t silver to 0.1 g/t silver.
The sampled structure subsequently has been confirmed by a geophysical survey and results from 220 rock chip channel samples taken in the area have been consistent with those previously reported. 73 of the new samples returned assay values in excess of 1 g/t gold with 36 samples returning values in excess of 3 g/t gold, over widths varying from 4 metres to 0.1 metre, to a maximum of 61.5 g/t gold over 3.9 metres. The structure is considered to be a prime drill target for a large-scale gold stockwork.
Sampling in 2007 also focused on the southern portion of the El Huato complex - most notably in an area where a copper-rich porphyry, cut by breccia dykes, has been discovered. Mineralization in this porphyry is disseminated in the sub-volcanic host rock. Channel sampling has been conducted in trenches, along outcropping veins, and across other outcropping mineralization. Trench sampling has returned values of up to 2.9% copper over 15 metres.
Latest results are tabulated below. Results are shown as averages over the length of trenches (Table 1) and veins (Table 2), and as single rock samples from outcrop (Table 3).
Table 1: Southern El Huato - Trenches containing Copper
|D1503305-09 & D0903185-192||2.31||10.70||3.92||16.67||20.0||0.7|
Table 2: Southern El Huato - Average Values over Length of Copper/Gold Veins
Table 3: Southern El Huato - Rock Samples Containing Copper
Ningomine and Loma Redonda
These areas, situated north and southwest of El Huato, respectively, were discovered by Company geologists prospecting in the Copper Duke area. They contain quartz veins associated with granodioritic dykes with moderate silicification and serecitization. Malachite is found disseminated in granodioritic rocks.
On February 8, 2007, the Company reported assays results from 113 samples, taken predominantly from a 1.5 sq. km area in Ningomine, three kilometres to the north of El Huato, and from a 2.5 sq. km area in Loma Redonda, four kilometres to the southwest of El Huato. Significant results ranged from 17 g/t gold to 0.1 g/t gold and from 727 g/t silver to 0.1 g/t silver, over widths of 2.0 metres to 0.2 metres.
Since January 2007, a total of 20 additional channel samples have been taken from Loma Redonda, of which half returned assay values in excess of 1% copper, to a maximum of 15% copper.
Rio Catamayo lies south of El Huato along the same mineralized trend and was discovered by Compnay geologists doing geological traverses through the area. Small porphyritic dykes outcrop along the river Catamayo. These dykes commonly contain stockworks of quartz veins and hydrothermal brecciation with argillic alteration and local silica with copper carbonate, pyrite, chalcopyrite and iron and copper oxides. Geochemical sampling produced values of up to 2.15 g/t gold and 1.33% copper over 18 metres of continuous sampling.
El Palton was discovered in February of 2007 by Company geologists working to the west of El Huato. This gold target contains highly oxidized and leached quartz-magnetite veins with wide zones of argillic alteration with brecciated texture. The veins and veinlets are found in porphyry dykes with quartz lenses up to 8 metres wide, in a parallel formation with local stockworks of very fine veins and massive stibnite. The wall rock is predominantly propilitized granite. Geochemical sampling of the area produced values of 10.13 g/t gold over 0.5 metres and 19.07 g/t gold over 0.3 metres.
Figure 2 Above: Copper Duke El Huato Drilling Targets