Greystar zooms in on Angostura

Reassured by the government’s hardened stance against armed rebels and having raised sufficient funds, Greystar Resources (GSL-T) is gearing up to renew drilling at its Angostura gold-silver property in northeastern Colombia.

Angostura, which sits near the Venezuelan border, gained notoriety in mid-1998 when an employee of the project’s drilling contractor was kidnapped by the infamous Revolutionary Armed Forces of Colombia (FARC). The driller and his subsequent replacement were eventually freed unharmed, and exploration resumed, albeit at a much slower pace.

Earlier this year, safety concerns were raised again, when Strathcona Mineral Services of Toronto refused to visit the site because of “security considerations and time constraints.” The geological consulting firm was hired to update an earlier report it had authored in 1999; that investigation also excluded a site visit, which normally would have occurred in both cases.

However, since then, newly elected Colombian President Alvaro Uribe has made good on his promise to suppress rebel groups throughout the country. Shortly after assuming office in early August, he declared a state of emergency and then created two security zones covering parts of the northeastern provinces of Sucre, Arauca and Bolivar. Both measures grant authorities the right to arrest suspects at whim, and the latter gives additional powers to the military, such as the right to restrict civilian movements and impose curfews.

More security zones are promised, and the measures may soon get a US$430-million financial boost from the U.S.. President George W. Bush is pushing Congress to approve the package by October, which would add to the US$2 billion in foreign aid that the war-torn South American country has received over the past few years.

According to Greystar, where Angostura is concerned, two fully manned stations are to be erected near the rugged, 60-sq.-km property. A third will be installed elsewhere, but still in the Santander or neighbouring Norte de Santander province.

That being said, the upcoming campaign will entail 20,000 metres of drilling, plus 1,200 metres of drifting and bulk sampling. Holes will be collared to infill the known resource and test some of its higher-grading pockets.

The program will be funded using proceeds from a $5-million private placement closed earlier this summer. The financing saw 20 million units issued at 25 apiece. A unit consists of a share and half a warrant, with a full warrant entitling the holder to buy another share by mid-June 2003 at 30.

Dundee Securities, the underwriter, was paid $250,000 and granted 600,000 treasury shares. The firm also received 1.6 million warrants, which can be converted into units at 30 apiece until mid-October 2003.

In 1999, Kinross Gold (K-T), which then held one-fifth of Greystar, estimated Angostura’s main resources at 96 million tonnes grading 1.6 grams gold and 5.8 grams silver per tonne. The estimate is based on a cutoff grade of 0.5 gram gold, which, when raised to 3 grams, deflates the deposit to 9.3 million tonnes but pumps the grade up to 6 grams gold and 11.4 grams silver.

Los Loches

The separate Los Loches area was pegged with 335,000 tonnes grading more than 3 grams gold. It was excluded because it could not possibly support an underground operation on its own.

Kinross relied on results from 52,000 metres in 181 core holes sunk by Greystar over the preceding four years. The hole-spacings are too wide for the measured category, so all the resources are classified as indicated or inferred.

Mineralization is generally controlled by northeasterly trending and steeply dipping structures that cut a suite of porphyritic diorites to quartz-monzonites that are themselves emplaced in the Proterozoic-aged Bucaramanga Gneiss. The structures are mostly characterized by single veins, stockworks or a series of closely spaced, parallel veins.

Grades are higher in the veins than in the host rocks, especially in vertically plunging shoots that form along intersections of the veins with crosscutting faults or shear zones. However, shear zones up to 300 metres long and 50 metres wide are common, and, in these structures, bands of pyrite up to a metre thick can be relatively high in gold and silver.

The widths of the veins vary from less than 2 metres individually to between 20 and 50 metres when they form a series. Drilling has cut the system as deep as 400 metres below surface, though most holes ended more than 100 metres closer to surface.

Oxidization is widespread and extends 170 metres below surface throughout most of the deposit. Gold recoveries in preliminary metallurgical tests were higher for oxidized mineralization than for primary material, exceeding 90% in cases. A refractory component appears to be associated with the primary zones.

Specks

Where native gold occurs, it appears as small grains in close association with pyrite or in matrices of silica and opal replacement. In the case of oxidized rocks, specks of the yellow metal are found on limonite coatings of vugs in quartz. No nugget effect is apparent.

According to Strathcona, 80% of the contained gold is hosted by veins, and of that, 43% is hosted by the high-grade shoots. Hence their geometry, grade-continuity and quantity are vital to the project’s future, whether it is advanced as an open-pit or underground operation (or both).

So far, Greystar has mapped more than 60 veins and mineralized structures over a strike length of several kilometres and a width of 1.5 km. The system extends for 1,000 metres in the vertical direction (elevations at Augostura vary from 2,800 to 3,500 metres above surface), where it remains open.

Strathcona calls for 50-by-50-metre drill patterns to be followed in the case of disseminated mineralization, and at least half as tight for the shoots, above and below the proposed development levels. The underground workings will be driven beneath the conceptual pit designed by Kinross.

Drilling will begin once the new security measures are in place. At least four rigs, two of which are owned by Greystar, are to be employed.

Greystar has more than 15 million shares outstanding, having recently consolidated its shares on a 5-for-1 basis. At last report, Kinross held 1.4 million shares, or nearly 9.3% of the company.

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