Antares, Mansfield hit new zone at Rio Grande (February 11, 2008)

VANCOUVER — Stepout drilling by Rio Grande joint-venture partners Antares Minerals (ANM-V, ANMFF-O) and Mansfield Minerals (MDR-V, MFMNF-O) has identified significant copper-gold mineralization in a previously untested zone on the project, located in northwestern Argentina’s Salta province.

Hole 56 cut215 metres (essentially from surface) of 0.42% copper, 0.5 gram gold per tonne and 7.1 grams silver in the No. 7 zone, located on the western margin of the project. The intercept includes a 48-metre interval grading 0.82% copper, 1.3 grams gold and 8.7 grams silver.

Mansfield director John Leask describes hole 56 as “a big stepout on the west side” that could have significant tonnage implications.

“It was a blind shot — no geochem, no geophysics, no trenches, nothing — a 700-metre stepout right in mineralization, right off the collar,” Leask says.

The No. 7 zone has a thicker colluvium cover than most of the Rio Grande project area with very little outcrop, rendering soil sampling much less effective. Mineralization is open to the north, south and likely to the west. Like most of the mineralization encountered so far at Rio Grande, it is partially to completely oxidized and shows minimal transport of secondary copper minerals.

“With the discovery of encouraging copper-gold mineralization at the No. 7 zone, we have at least four areas where we have encountered longer runs of higher-grade copper-gold mineralization,” said Antares president and CEO John Black in a statement. “These four areas have the potential to collectively host a significant volume of better-grade mineralization and are interconnected by zones with lower grades.”

Drilling also tested the North and Sofia zones. Hole 45 on the North zone — collared 150 metres east of similar mineralization in hole 43 — cored 132 metres (from 128 metres down-hole) grading 0.38% copper, 0.4 gram gold and 2.8 grams silver, including 50 metres of 0.49% copper and 0.46 gram gold.

Hole 50 on the Sofiazone returned 111 metres (from 114 metres) of 0.42% copper, 0.41 gram gold and 8.5 grams silver. The intercept includes a 25- metre interval of 0.64% copper, 0.8 gram gold and 16.2 grams silver.

Copper-gold mineralization at Rio Grande is hosted in a sequence of intermediate subvolcanic intrusives with variable degrees of potassic, calcic and propylitic alteration. Original chalcopyrite and magnetite mineralization occurs as disseminations and fracture fillings. Chalcopyrite has subsequently been oxidized, to varying degrees, to depths of at least 300-400 metres. Oxidation is typically in situ, showing little to no copper remobilization.

Antares is operator at Rio Grande, with the project held equally with Mansfield. In mid- 2007, Mansfield completed a $5.25- million financing in Antares for a 9.8% stake in its partner.

Shares of Antares climbed 12% on the drill results, closing up 41 at $3.91 apiece, while Mansfield posted a 10% gain to $3.70.