MDR Goldrock Mines Corporation

Mansfield Minerals Inc. (Mansfield or the "Company") (TSX VENTURE: MDR) is pleased to provide a prefeasibility study update on the Lindero heap leach oxide gold deposit, Salta Province, Argentina. AMEC Americas Limited is over-seeing completion of this study with a delivery date currently projected in late Q4 2009. The Lindero gold deposit hosts an NI 43-101 compliant measured and indicated oxide gold resource of 70.3 MT grading 0.72 grams/tonne containing 1.6 million oz gold. There is an additional 270,000 oz gold at 0.61 grams/tonne in the inferred category (Golder Associates, 2008). The afore-mentioned resources are calculated at a cut-off grade of 0.45 grams/tonne gold.

The AMEC prefeasibility study is presently modeling an open-pit heap-leach operation which suggests a mining rate (total material moved) ranging from 12 to 22 million tonnes per annum, delivering 7 to 9 million tonnes per year to the leach pad at strip ratios in the 1.0 to 1.3 to 1 range. The above projections are based upon the project metrics that are presently known, however the Company cautions that the mineral resources are not mineral reserves and have not been demonstrated to be economically viable.

Metallurgical studies are ongoing at Kappes Cassiday & Associates in Reno, Nevada, under the supervision of American Au Ag Associates. A high pressure grinding roll system appears to be the appropriate crushing system to optimize costs, recoveries, and project economics. Heap leach oxide gold recovery is estimated at 70%+ (previously announced). The Lindero gold deposit carries an average copper grade in the range of 0.10%. Leach tests by Kappes Cassiday show a copper content in leach solution of 153.3 ppm, well below the threshold at which the copper content could be of concern with respect to the gold recovery and cyanide consumption. The Company does not plan on recovering copper.

The Company has engaged Vector Argentina S.A., a division of an international engineering group, to commence the mine permitting process.

This news release has been reviewed by Gordon P. Leask, P.Eng., President and CEO of the Company, and a Qualified person ("QP") as defined by National Instrument 43-101 (Standards of Disclosure for Mineral Projects).

About Mansfield Minerals Inc. Mansfield is a mining exploration company which has focused its activities in northwestern Argentina since August 1994. The Company is currently progressing with its pre-feasibility study on the Lindero gold project.

On behalf of the Board of Directors,

Gordon P. Leask, President & CEO

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. Factors that could cause actual results to differ martially from those in forward-looking statements include changes in metal prices, changes in the availability of funding, unanticipated changes in key management personnel and general economic conditions. Mining is an inherently risky business. Accordingly the actual events may differ martially from those projected in 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.

Contacts: Mansfield Minerals Inc. Gordon P. Leask President & CEO (604) 681-4462 (604) 681-0180 (FAX) info@mansfieldminerals.com www.mansfieldminerals.com