Vancouver — Drilling by
Assays from 32 holes show thick intercepts (up to 386 metres) of porphyry copper mineralization, much of which demonstrates high leachability (leachability refers to the dissolution of copper into solution, either through sulphuric acid, for oxide mineralization, or sodium cyanide, for secondary sulphide mineralization).
Highlights include the following:
— hole 44 — 262 metres (from a down-hole depth of 16 metres) grading 0.38% copper with 87% leachability, including 70 metres grading 0.58% copper with 89% leachability;
— hole 83 — 140 metres (from 30 metres) averaging 0.4% copper with 94% leachability, including a 50-metre section of 0.53% copper with 95% leachability;
— hole 94 — 220 metres (from 50 metres) assaying 0.43% copper with 93% leachability, including 16 metres of 0.72% copper with 95% leachability;
— hole 111 — 214 metres (from 94 metres) grading 0.35% copper with 77% leachability, including a 22-metre section of 0.91% copper with 83% leachability.
The project was subjected to more than 32,000 metres of drilling (114 holes) in 2004. An updated resource estimate by AMEC is expected in the new year.
Lumina did metallurgical testing on mineralized material to ascertain the leachability of contained copper. Bottle-roll testing of both oxide and sulphide material recovered from drilling confirms high leachability.
A second phase of copper leachability testing, supervised by SGS Lakefield, is under way. The data will form the basis of a prefeasibility study of a commercial-scale copper leaching operation. Copper cathode would be produced on-site, with no concentrate shipments to a smelter, enabling Lumina to reserve funds for the exploration of lower-grade copper deposits.
Vector Engineering has tabled a preliminary infrastructure study, outlining the design and layout of the heap leach pad and dumps for a 150,000-tonne-per-year operation.
Regalito is an Andean-type porphyry copper deposit associated with a cluster of dacitic porphyry intrusives and hydrothermal-contact breccias, and exhibits typical potassic and phyllic alteration. The dacites intrude Paleozoic granites and are associated with the regional, northeast-trending Caserones Fault. The predominant copper mineral is chalcocite in the supergene enrichment zone at Regalito. Mineralization in the hypogene zone consists of pyrite and chalcopyrite with minor bornite and molybdenite.
An unclassified resource of about 200 million tonnes grading 0.5% copper (using a 0.3% copper cutoff grade) had been outlined by previous operator
Lumina Copper entered into the option to acquire Regalito in late 2003. The agreement calls for payments totalling US$900,000 over eight years, plus additional cash payments if copper prices remain above US$1 per lb. for a calendar year. A variable 1-3% NSR will be applied to production, dependent on copper prices.
The company has 10 copper projects, at various stages of development, in Chile, Peru, Argentina and Canada.
There are 14.4 million shares outstanding, and the stock recently traded at $5.60.
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