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Cerro Chacay

Cerro Chacay, Chile (100%)

The Cerro Chacay Property is located 12km southeast of Global Copper Corp's Relincho copper project, and 50km east of the city of Vallenar in the III Region of Chile.


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Geology and Mineralization

The Property which has a mean elevation of 2700 meter hosts a well defined porphyry copper prospect of probable Paleogene age that has previously been drill tested by several companies.

The prospect has been geologically mapped and comprises quartz feldspar and diorite porphyries emplaced into andesitic volcanics of the Upper Cretaceous age Hornitos Formation. A classic zoned porphyry alteration suite of external propylitic alteration surrounding a quartz-sericite core is developed over a distance of 3500m, oriented west northwest. A strongly developed quartz sulphide stockwork coincident with the quartz feldspar porphyry occurs over an area of 1600 x 1400m on the Cerro Colorado hill. This hill has an elevation difference of 300m over the surrounding valleys and hosts a classic leached cap, which drilling has shown to vary from 50 to 200m in thickness.

Underlying the leached cap, a partially oxidised flat lying chalcocite enrichment blanket has been intersected in drilling and although assays are not available for most of the holes, is currently interpreted to be between 30 and 110m thick, with the elevation at its top being approximately 2600m. Based on the available assay information, the grade of this blanket is expected to be in the 0.40-0.70% CuT range.


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Previous Drilling

In March 2005, Minera Cielo Azul Limitada (MCAL), then a subsidiary company of First Quantum Minerals Ltd (FQM), drilled a total of 7 RC holes at its 100% owned Cerro Colorado-Chacay porphyry copper property. Three of these holes intersected porphyry copper style mineralization but were only assayed for total copper. The significant intersection were as follows:

Hole

From

To

Meters

%CuT

CHCRC02

14

42

28

0.51

CHCRC05

190

198 end of hole

8

0.56

CHCRC06

82

160

78

0.44

- including

102

126

24

0.73


Coro acquired MCAL in 2005, and has recently recovered and re-assayed 77 of the mineralized samples for acid soluble (CuSol) and cyanide soluble (CuCN) copper. This re-assaying indicates that the mineralization encountered in holes CHCRC05 and 06 is comprised of mixed copper oxide and chalcocite, exhibiting high total solubilities, rather than mixed oxides and primary sulphides as previously inferred. Mineralization in CHCRC02 was copper oxide. The high grade section in CHCRC06 was re-assayed in its entirety and found to average 24m @ 0.76%CuT, 0.34%CuSol, and 0.27%CuCN, for a total solubility of 79.5%. A correlation coefficient of 0.99 was obtained between the original FQM/MCAL assays and MCAL % CuT reassays.

All FQM-MCAL RC holes were sampled on a 2 meter continuous basis, with samples riffle split on site and one quarter sent to the ALS Chemex laboratory in La Serena. Samples were transported to the laboratory by FQM-MCAL personnel. Samples were prepared using the following standard protocol: drying, crushing to better than 95% passing 2 millimeter, splitting and pulverizing a 200 gram subsample to 95% passing 0.106 millimeter. All samples were analyzed for %CuT; some samples were also assayed for Au. The 2007 MCAL re-assaying program comprised the recovery of 77 selected FQM-MCAL RC samples stored on site and their shipment to Andes Analytical Assays, Santiago Chile for preparation and sequential assaying for CuT, CuSol and CuCN, as well as for Au and Mo. A correlation coefficient of 0.99 was obtained between the original FQM-MCAL and MCAL %CuT reassays.

Previous drilling by the following companies is outlined below. The drillhole locations and summary geological information is available for some of the pre FQM drilling but it has not been possible to obtain the corresponding assay information.

Cerro Colorado-Chacay Drilling History

Company

Year

Holes

Meters

Results

 

 

 

 

 

Anglo American

1994

11

2,160

Unavailable

BHP Billiton

1996

6

1,457

Unavailable

Metallica Resources

2002

6

1,554

Unavailable

First Quantum Minerals

2005

7

1,366

Available

 

 

 

 

 

Total

 

30

6,537

 



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What's next?

A short drilling campaign is now being scheduled to twin some of the previous holes that were reported to have intersected mineralization.
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This page was created on Fri Sep 10, 2010 at 1:37:28 PM Pacific Time.