The Taca Taca copper/gold/molybdenum project, comprising approximately 2,500 hectares, is located in the Puna region of north western Argentina in Salta province, approximately 230 kilometres west of the provincial capital of Salta and 120 kilometers east of the world's largest copper mine, Escondida.
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 prior to Lumina's current drill program 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 had been completed on the property at the end of the Rio Tinto program.
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.
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 represented a new deeper target type at the project.
LUMINA COPPER DRILLING
Lumina filed an updated National Instrument 43-101 (NI 43-101) compliant technical report, as amended on January 22, 2010, entitled "Amended Taca Taca Technical Report". The Report was authored by Robert Sim, P. Geo., a Qualified Person as defined by NI 43-101. Additional work recommended included conducting preliminary metallurgical testwork, infill drilling within the current resource to reduce the average drillhole spacing to approximately 250 metres and exploration drilling to test for extensions of the deposit.
Following the results of the Report, Lumina completed a technical review to determine the appropriate development route for the project. This review included mine planning studies and an evaluation of the expansion potential of the existing mineral resource. The results of the review showed that potential additional value may be added to the project by extending the existing mineral resource to the north and identifying new areas of higher grade mineralization to the south and at depth and recommended that an exploration program be conducted.
In May 2010, Lumina commenced the exploration program with a deep ground penetrating geophysical survey utilizing Quantec Geoscience's proprietary Titan24 Deep Earth Imaging System to identify buried copper porphyry bodies and was completed in June 2010. In August 2010, Lumina commenced a first phase drill program to evaluate the deep targets generated from the Titan24 survey and potential northern extensions of the existing mineral resource. In addition, a preliminary metallurgical testing program was initiated to evaluate the amenability of the Taca Taca mineralization to flotation and concentration.
January 11, 2011, Lumina announced preliminary results from its initial metallurgical testing program which indicate that a high grade copper concentrate and a saleable molybdenum concentrate can be produced from both supergene and primary mineralized material.
The exploration and development program on the Taca Taca Property was expanded to include:
approximately 99,500 metres, including geotechnical drilling;
a comprehensive metallurgical testing program; and
engineering studies, including mine planning, process engineering and design, infrastructure layouts and logistics including transportation, water and power supply.
On November 15, 2011 the company released an updated, interim mineral resource estimate. The estimate significantly increased the known sulphide copper, gold and molybdenum mineral resources and included an initial estimate of the oxide gold resources contained in the leached cap.
On May 7, 2012 the Company announced an updated, interim mineral resource estimate that again significantly increased the known sulphide copper, gold, molybdenum and oxide gold mineral resources over the previous mineral resource estimate released in November 2011.
On Nov 21, 2012 the company was pleased to announce that it has received an updated mineral resource estimate on its 100% owned Taca Taca copper/gold/molybdenum project. The estimate significantly increases the known sulphide copper, gold and molybdenum resources over the previous mineral resource estimate released in May 2012.
At a 0.3% copper equivalent cut-off, total contained sulphide copper in the Indicated resource category is estimated to be 21.1 billion pounds of copper, while total contained sulphide copper in the Inferred resource category is estimated to be 7.6 billion pounds of copper.
The base case cut-off grade for the sulphide mineral resource estimate has been decreased from 0.4% copper equivalent to 0.3% copper equivalent to align the mineral resource estimate with the net smelter return cut-off that will be used to define the parameters of the mine plan to be incorporated in the forthcoming Preliminary Economic Assessment ("PEA"). There has been no change to the cutoff grade, of 0.2g/t gold, for the oxide gold resource estimate.
The updated mineral resource estimate shows that the sulphide mineral resource remains open to depth in some areas and along the southern boundary of the deposit's northeastern limb. The boundaries of the oxide gold resource appear to be fully defined.
The salient details of the updated National Instrument 43-101 compliant ("NI 43-101") mineral resource estimate can be found in the news release Nov 21, 2012:
(Lumina Reports Updated Mineral Resource Estimate At Taca Taca Copper-Gold-Molybdenum Project, Argentina - Significant Increase In Resources)
For more details please see the Resource Summary page for the updated Resource Estimate, or the full NI 43-101 Technical Report Below.
[updated: JAN 2-13]
||NI 43-101 Technical Report :
Taca Taca Porphyry Copper - Gold - Molybdenum Project, Argentina
Effective Date :
October 30 - 2012
Release Date :
January 4 - 2013
Authors and Qualified Persons :
Robert Sim, P.Geo. (Principal)
Bruce Davis, FAusIMM
Don M. Larson, PhD PE