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The Taca Taca Property is located approximately 230 km west of the city of Salta, in the western Salta province, in the Puna (altiplano) region of northwest Argentina. Lumina Copper has a 100% interest in the property that comprises thirteen mining concessions covering 2,546 ha. The nearest village to the property, Tolar Grande, has a population of approximately 100 people and is located 32 km to the east of the Taca Taca Property.
Copper mineralization was first recognized at the Taca Taca Property in the mid-1960s and the property has previously undergone several exploration campaigns by Falconbridge, GAMSA, Corriente, BHP, and Río Tinto. The most recent activity involved drilling of eight diamond drill holes by Rio Tinto in 2008. A total of 29,036 metres of diamond and reverse circulation in 164 holes has been completed on the property to date.
Hypogene, supergene and oxide porphyry Cu-Mo-Au mineralization at Taca Taca is typical of Andean porphyry deposits and is hosted by Oligocene granitic porphyry intrusions. Hypogene chalcopyrite mineralization is common beneath the quartz sericite altered portion of the porphyry and is capped on the west and north side of the porphyry by a zone of supergene enrichment. The supergene zone is generally 20 metres to 60 metres thick and consists of chalcocite and covellite coatings on hypogene chalcopyrite and pyrite. A 200 to 300 metre thick leached cap sits above most of the supergene zone and within this there are isolated occurrences of remnant (only partially leached) oxide/supergene mineralization that are dominated by chrysocolla, malachite, and brochantite. Other related types of mineralization identified on the property include exotic Cu-oxide occurrences beneath the Salar de Arizaro and Au-Cu quartz-hematite veins immediately to the north and west of the porphyry.
The recent recognition of hypogene high-sulfidation ("enriched") copper mineralization at Taca Taca may allow for significant tonnages of higher grade material to remain undetected within and below the current drill pattern provides a new rationale for targeting exploration. This zone of higher grade copper mineraliztion consists of bornite, chalcocite and digenite is considered to be the most attractive exploration target on the Taca Taca property.
The most recent drill program at the project was conducted by Rio Tinto in 2008 and enriched, high grade copper was intersected in a number of drill holes and is highlighted by TTBJ-0007 which graded 426 meters grading 0.75% copper, 0.16 grams/tonne gold and 0.025% molybdenum (0.99% copper equivalent*) including 120 meters grading 1.40% copper, 0.21 grams/tonne gold and 0.035% molybdenum (1.73% copper equivalent*); TTBJ-0006 that returned 248 meters grading 0.89% copper, 0.11 grams/tonne gold and 0.036% molybdenum (1.16% copper equivalent*) and TTBJ-0003 that returned 195 meters grading 0.78% copper, 0.29 grams/tonne gold and 0.030% molybdenum (1.12'% copper equivalent*).
Previous to Rio Tinto's drill campaign only open-pittable copper had been targeted at Taca Taca but the high grade of copper mineralization encountered in Rio Tinto's drilling would allow underground exploitation by bulk mining methods. This represents a new deeper target type at the project. Consequently, a large area of the property now requires deeper exploration below the base of previous drilling. In 2010 Lumina will focus on exploring the deeper potential at Taca Taca by conducting a deep-penetrating geophysical survey targeting bulk underground mineable copper which may lead to further work. Additionally, scoping work will be carried out on open pit and underground known mineralization.
Lumina is currently evaluating a number of strategic alternatives to enhance the value at Taca Taca, including evaluating the potential for a deeper, higher grade target, expansion potential of the known mineralization and mine planning studies to evaluate various alternative mining methods.
Lumina released a new NI 43-101 compliant resource estimate in October 2008 that can be viewed or downloaded from link provided below
Robert Sim, P.Geo served as the Qualified Persons responsible for the preparation of the Technical Report as defined in National Instrument 43-101, Standards of Disclosure for Mineral Projects.
Effective Date: Oct 9 - 2008, Report Date: Nov 24, 2008
Technical Report Dated January 22, 2010 - PDF link:
* Copper Equivalent assumptions: Metal prices, US$1.50/lb Cu, US$600/oz Au and US$9.00/lb Mo
The formula used is as follows CuEQ= Cu% + (Au g/t x 0.583) + (Mo% x 6)
[updated: JAN 2010]
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