Antares, Mansfield hit best Rio Grande intercept yet (September 14, 2007)

Vancouver – Rio Grande project joint venture partners Antares Minerals (ANM-V, ANMFF-O) and Mansfield Minerals (MDR-V, MFMNF-O) got a market rise following the latest drill assays from its northwestern Argentinean copper-gold property returning some of the best results to date.

Hole RGA-07-034, collared as a 150-metre northerly step out on the Sofia North zone, cut 189 metres (from 140 metres down-hole) grading 0.7% copper and 0.67 gram gold per tonne, the best intersection so far from the project, and included higher-grade intervals of up to 12 metres at 2.2% copper and 1.85 grams gold.

Higher grade sections of the hole occur in a breccia-textured feeder structure.

“We now have strike and dip extensions with feeder zone grades,” stated Mansfield president and CEO Gordon Leask in the release. “As our geologic understanding of the deposit has increased, so has the drill success. For good projects it has been said “The more you work them, the better they get”. This is certainly the case for Rio Grande.”

Mineralization in the hole was encountered shallower than anticipated and remains open to the north and west. RGA-07-034 is located just northwest of the two previous best holes on the project, RGA-06-026 that cut 158 metres of 0.46% copper and 0.51 gram gold and RGA-06-024 returning 128 metres of 0.47% copper and 0.71 gram gold.

The eight holes, totaling about 3,600 metres, with results returned so far are part of a 15,000-metre program and were positioned to test for extensions of mineralization to depth and along strike. With 21 holes completed as of September 14th, assays are pending for 13 holes while three rigs continue to work the property.

Work by the joint venture partners now shows the Discovery and Sofia zones to be continuous, forming a large zone of copper-gold mineralization on the eastern portion of the ring structure.

Antares president and CEO, John Black, stated upcoming drilling will be focused on the previously untested North zone located northwest of the Sofia zone.

Antares is operator on Rio Grande and is earning a 50% joint venture interest by spending by spending US$3.4 million and issuing 300,000 shares to Mansfield by September 30, 2007. Earlier this year Mansfield completed a $5.25-million financing in Antares to hold about 9.8% of its JV partner.

Shares of Antares and Mansfield both reacted favourably to the Rio Grande drill results, notching up 6 to $3.69 and 15 to $3.40 respectively in September 14th trading.