Mansfield Minerals Inc.

Mansfield Minerals Inc.

January 18, 2008 09:02 ET

Mansfield Minerals Inc.: Huge Stepout-Big Copper/Gold Intercept at Rio Grande West

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Jan. 18, 2008) - Mansfield Minerals Inc. (the "Company") (TSX VENTURE:MDR) announces that its joint venture partner, Antares Minerals Inc. ("Antares") has reported results from an additional twelve holes (5,500 metres) of the thirty-five hole (16,238 metre) diamond drilling program completed in late 2007 at the Rio Grande copper-gold project in northwestern Argentina. Highlights from these holes include the discovery of significant copper-gold mineralization in the previously un-tested #7 zone along the western margin of the Rio Grande system as well as further strong results from the North and Sofia zones. Some of the more significant intercepts are as follows:

- RGA-07-56 (#7 Zone): 135 m with 0.53% Cu, 0.65 g/t Au, and 8.9 g/t Ag

- Includes 48 m with 0.82% Cu, 1.28 g/t Au, and 8.7 g/t Ag

- Discovery of new Cu-Au zone along western margin of Rio Grande system

- Mineralization commences from near surface

- RGA-07-45 (North Zone): 132 m with 0.38% Cu, 0.40 g/t Au, and 2.8 g/t Ag

- Includes 50 m with 0.49% Cu, 0.46 g/t Au, and 2.7 g/t Ag

- Collared 150 m east of similar mineralization in RGA-07-43

- RGA-07-50 (Sofia Zone): 111 m with 0.42% Cu, 0.41 g/t Au, and 8.5 g/t Ag

- Includes 25 m with 0.64% Cu, 0.79 g/t Au, and 16.2 g/t Ag

- Collared 150 m north of well mineralized RGA-07-34

John Black, President and CEO of Antares Minerals Inc. commented as follows:

"The results from the 2007 drilling campaign at Rio Grande continue to meet and exceed our expectations. We are particularly encouraged by the consistent zone of higher gold grades encountered in hole RGA-07-56 (48 m averaging 1.28 g/t Au and 0.82% Cu with a maximum individual interval of 2.32 g/t Au). With the discovery of encouraging copper-gold mineralization at the #7 zone, we have at least four areas where we have encountered longer runs of higher grade copper-gold mineralization. These four areas have the potential to collectively host a significant volume of better grade mineralization and are interconnected by zones with lower grades. We are currently working with our partners, Mansfield Minerals, to design an extensive infill drilling program with an objective to complete an initial resource estimate at Rio Grande by the end of 2008. Drilling will recommence in February, 2008."

Mansfield Minerals Inc.
Rio Grande Project, Northwestern Argentina
Drilling Results Reported January 18, 2008
Drill Hole Copper Gold Silver
Number Zone Interval Length (%) (g/t) (g/t)
RGA-07-44 Discovery 469-504 m 35 m 0.37 0.25 3.0
128-260 m 132 m 0.38 0.40 2.8
RGA-07-45 North incl. 128-154 m 26 m 0.44 0.51 2.9
incl. 163-199 m 36 m 0.32 0.38 4.2
incl. 210-260 m 50 m 0.49 0.46 2.7
203-223 m 20 m 0.28 0.19 1.6
325-435 m 110 m 0.36 0.32 3.4
incl. 325-346 m 21 m 0.41 0.36 3.4
RGA-07-46 North incl. 352-406 m 54 m 0.42 0.38 3.6
incl. 417-435 m 18 m 0.32 0.29 3.7
462-484 m 22 m 0.26 0.13 3.8
RGA-07-47 North 57-117 m 60 m 0.36 0.37 3.2
41-96 m 55 m 0.33 0.26 2.6
RGA-07-49 Sofia North 119-135 m 16 m 0.25 0.09 0.9
12-225 m 213 m 0.37 0.37 6.1
incl. 12-42 m 30 m 0.32 0.32 2.3
incl. 50-104 m 54 m 0.39 0.40 4.6
RGA-07-50 Sofia North incl. 114-225 m 111 m 0.42 0.41 8.5
incl. 152-177 m 25 m 0.64 0.79 16.2
incl. 250-262 m 12 m 0.23 0.17 3.3
incl. 292-304 m 12 m 0.22 0.31 8.4
RGA-07-51 #7 No significant intervals to report.
225-243 m 18 m 0.23 0.27 2.6
RGA-07-52 Sofia North 292-312 m 20 m 0.23 0.23 4.2
RGA-07-53 #7 No significant intervals to report.
121-133 m 12 m 0.30 0.65 7.5
RGA-07-54 North 272-291 m 19 m 0.41 0.29 3.5
307-329 m 22 m 0.21 0.18 1.8
56-74 m 18 m 0.24 0.34 2.9
80-98 m 18 m 0.22 0.28 3.9
118-151 m 33 m 0.19 0.34 11.1
227-261 m 34 m 0.25 0.31 3.7
RGA-07-55 North 276-291 m 15 m 0.18 0.27 2.6
301-315 m 14 m 0.25 0.25 5.1
404-416 m 12 m 0.35 0.44 5.6
422-432 m 10 m 0.25 0.33 3.6
543-567 m 24 m 0.36 0.40 5.1
5-220 m 215 m 0.42 0.49 7.1
incl. 21-47 m 26 m 0.32 0.29 4.2
RGA-07-56 #7 incl. 53-79 m 26 m 0.25 0.26 3.9
incl. 85-220 m 135 m 0.53 0.65 8.9
and 101-149 m 48 m 0.82 1.28 8.7

- intervals have been rounded to the nearest metre.

Discussion of Results

The objectives of the recently completed 15,000+ metre program were (1) to follow-up on encouraging results from previous drilling campaigns in the Sofia and Discovery Zones, (2) to drill test the remaining two-thirds of the system that has not been adequately explored to date, and (3) to provide an initial drill test of the satellite Northeast Target which bears geological and geochemical similarities to the nearby Lindero gold deposit owned 100% by Mansfield.

Copper-gold mineralization at Rio Grande is hosted by a complex sequence of intermediate sub-volcanic intrusive rocks with variable degrees of potassic, calcic, and propylitic alteration and local late to post-mineral intermediate dikes. The mineralization originally consisted primarily as chalcopyrite and magnetite as disseminations and fracture fillings. The chalcopyrite has subsequently been partially to completely oxidized to green and black copper oxides to depths of 300-400 metres or more. Oxidation is typically in situ with little to no remobilization of copper.

The majority of the twelve holes presented in this release were drilled in the previously poorly tested North and #7 targets along the northern and western margins of the Rio Grande system. Significant mineralized intervals from the drill holes are listed in the table above. All of the holes were drilled at angles of 50-75 degrees from horizontal to better traverse potentially sub-vertical zones of mineralization. Reported mineralized intervals represent down-hole lengths and not true thicknesses as there is currently insufficient geological data to calculate true thicknesses.

Drill hole RGA-07-44 was drilled to complete the deeper hole of a drill fence at the southern end of the Discovery zone. Mineralization encountered deep in this hole is thinner and lower grade than elsewhere in the Discovery zone indicating that the zone is beginning to terminate to the southwest.

Drill holes RGA-07-45, 46, 47, and 55 were drilled in the North zone on north-south drill sections located approximately 150 meters apart. Holes RGA-07-45 and 46 both encountered long runs of moderate grade copper-gold mineralization near previously reported mineralization in RGA-07-43 and 48. The majority of these holes were drilled to the south but RGA-07-46 was drilled to the north to form a scissor pair with previously announced RGA-07-43. This pair of holes indicates that the east-west striking zone of mineralization most likely has a sub-vertical dip.

Drill holes RGA-07-49 and RGA-07-50 were drilled at the northern end of the Sofia zone approximately 150 metres to the northeast of well-mineralized hole RGA-07-34. The holes were drilled from the same pad but at 90 degrees to each other to help identify potential structural trends. Both holes encountered significant copper-gold mineralization with hole RGA-07-50 hosting an interval of 111 m with 0.42% Cu and 0.41 g/t Au which includes a sub-interval of 25 m with 0.64% Cu and 0.79 g/t Au. Further drilling will be warranted to see how this interval connects with mineralization encountered in RGA-07-34 (189 m with 0.70% Cu and 0.67 g/t Au). RGA-07-49 also hosts a 50 m interval containing 0.10% Mo with little Cu or Au. This occurrence is not well understood but warrants further investigation. Holes RGA-07-52 and 54 were drilled in the gap between the Sofia and North zones and only encountered narrow zones of low to moderate copper-gold mineralization.

Drill holes RGA-07-51, 53, and 56 were drilled in the #7 zone and are spaced approximately 400 metres apart in this poorly exposed and poorly explored portion of the Rio Grande system. This area has thicker colluvial cover than most of the project area. This means there is little outcrop and soil sampling is not very effective. Holes RGA-07-51 and 53 encountered no significant mineralized intervals and may have been drilled too far to the east to intersect the favorable horizon. Hole RGA-07-56 was drilled farther to the west and entered almost immediately into well mineralized rock including an interval of 135 m with 0.53% Cu and 0.65 g/t Au with a sub-interval of 48 m with 0.82% Cu and 1.28 g/t Au. This sub-interval has very consistent Au grades ranging from 1-2 g/t Au with a maximum individual assay value of 2.32 g/t Au. Mineralization remains open to the north, south and most likely to the west as well. As typical for most mineralized intervals encountered to date at Rio Grande, the mineralization has been partially to completely oxidized with little secondary transport of secondary copper mineralization.

A map of the drill hole locations has been posted on the Company's website and can be viewed at

This news release has been reviewed by John Black, Antares' President, who serves as the qualified person (QP) under the definitions of National Instrument 43-101. Antares' security, chain of custody and quality control is described on their website and can be reviewed at:

About Mansfield Minerals Inc.

Mansfield is a mining exploration company which has focused its activities in northwestern Argentina since August 1994. The Company's current significant properties and projects consist of mineral rights covering approximately 170 square miles in three Argentine provinces and one Canadian province. The Company is currently focused on two primary projects which include Lindero (gold) and Rio Grande (copper-gold). Antares has earned a 50% interest in the Rio Grande project from Mansfield and the two parties are currently formalizing a definitive joint venture agreement to fund ongoing exploration at Rio Grande on a 50/50 basis with Antares as operator.

On behalf of the Board of Directors,

Gordon P. Leask, P.Eng., President

Caution Regarding Forward-Looking Statements - This news release contains certain forward-looking statements, including statements regarding the business and anticipated financial performance of the Company. These statements are subject to a number of risks and uncertainties. Actual results may differ materially from results contemplated by the forward-looking statements. When relying on forward-looking statements to make decisions, investors and others should carefully consider the foregoing factors and other uncertainties and should not place undue reliance on such forward-looking statements. The Company does not undertake to update any forward looking statements, oral or written, made by itself or on its behalf.

The TSX Venture does not accept responsibility for the adequacy or accuracy of this release.

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