Mansfield Minerals Announces Positive Pre-Feasibility Results:

161,000 oz Average Annual Production in Years 1-5 at US$373/oz Cash Cost

Vancouver, British Columbia ? Mansfield Minerals Inc. (TSX.V ? MDR), March 22, 2010, Mansfield Minerals Inc. (?Mansfield? or the ?Company?) is pleased to announce the results from a National Instrument 43-101 compliant pre-feasibility study (the ?Study?) for its 100% owned Lindero gold project in Salta Province, Argentina.  The Study was completed by AMEC Americas Limited (?AMEC?) in association with American Au Ag Associates and Kappes Cassiday & Associates.  The complete Study will be filed on SEDAR and the Company's website within 45 days of the issue of this press release.  The Study contemplates conventional open pit mining operation and heap leach gold recovery. Over the initial three years of production 31.9 million tonnes of ore will be mined at an average grade of 0.81 grams/tonne containing 830,000 oz of gold.  Leach kinetics provide for the recovery of 499,700 oz/gold in years 1-3 with the remaining 83,800 oz recovered as leaching proceeds based on a 70.31% recovery.  Heap leaching over the first five years will produce an average of 161,000 ounces of gold at a cash cost of US$373 per ounce.  Highlights of the project economic estimates are summarized below.

1.     Project economics have been reported by AMEC on a pre-tax basis.

2.     Project economics include a 3% provincial royalty.

3.     Base case project scenario.

The Company is planning to have tax modeling completed independently to determine the after-tax project economics. The Company will report these results as soon as they are available.

In reviewing the study results, Gordon Leask, P.Eng., President and CEO of Mansfield stated:

?I am very pleased that the pre-feasibility study has demonstrated such robust project economics.  Lindero has the potential to create significant shareholder value.  We believe the project has extremely attractive characteristics, including projected gold production of 161,000 ounces annually at cash costs of US$373 per ounce during the first five years of operation. 

The mine plan in the pre-feasibility study is based on measured and indicated gold resources of 2.2 million ounces of gold at a 0.20 g/t cut-off.  In parallel with project development, we are currently considering further drilling with the objective of converting a portion of the additional 750,000 ounces of gold in the inferred resource category to the measured and indicated category at a 0.20 g/t gold cut-off.

We are now focused on advancing permitting at the project and have engaged Vector Argentina S.A. to further advance the mine permitting process.  As a conventional open pit heap leach project with good accessibility and project logistics, we believe the project could be in production in less than 24 months following receipt of necessary permits and obtaining sufficient financing. 

We look forward to aggressively moving forward with the Lindero project.  In the coming months we will also begin assessing all project financing and partnership opportunities to maximize shareholder value.?

1.     After refining and treatment charges.

2.     Considering total material moved.

3.     Includes a contingency of US$18 million.

1.     CIM definitions were followed for estimation of Mineral Resources and Mineral Reserves.

2.     Mineral Resources were constrained within an economic open pit shell, generated using a gold price of US$890 per ounce of gold, a processing cost of $3.07 per tonne, a mining cost of $1.10, a sales cost of $12 per ounce and a  metallurgical recovery of 70%.

3.     Mineral Reserves are estimated using a cut-off grade of 0.19 g/t Au, based on a gold price of US$775 per ounce.

4.     Mineral Resources are inclusive of Mineral Reserves.

5.     Mineral resources that are not mineral reserves do not have demonstrated economic viability.

Additional Details

The Study projects a 9.5 year mine life with cumulative production of 1.357 million ounces of payable gold based on the National Instrument 43-101 compliant Reserve Estimate.  Ore will be mined at an annual rate of 10.8 million tonnes, and due to favourable topography the life of mine strip ratio is 0.9:1 (waste to ore).  The topography is also favourable for the location of the leach pads and waste dumps with minimal earthworks required.

The current life of mine metallurgical recovery is estimated at 70.31% weighted average for all domains in Reserves based on a two stage conventional crushing and grind circuit with a grind size of a -3/8 inch p80 = 7mm.  Reagent consumption is expected to be modest (cyanide consumption of 0.436 Kg/tonne and lime of 2.75 Kg/tonne).  Limestone will be sourced locally and lime produced in a calcining plant.  Recent test work utilizing high pressure grinding roll (HPGR) crushers has demonstrated the potential for gold recoveries above the estimated life of mine average recoveries of 70.3% and at potentially lower operating costs.

Power will be generated utilizing natural gas supplied by a 130km connection to the regional Gasoducto de la Puna gas pipeline which was built by the Salta government to encourage mining and other economic development in the Puna region.  The estimated capital cost of the natural gas connection is US$9.9 million.  Power cost is estimated at US$0.062 per kwh based on a natural gas price of US$5 per MMBTU. 

Environmental, Permitting, and Community Relations

The Company is advancing the permitting process with significant base line environmental monitoring and other work completed to date.  Estimates and results from the Study will be a significant input for the final permitting applications.  The Company has also focused efforts on consultation with local communities and other stakeholders to ensure that concerns are properly addressed.

Qualified Persons

Jay Melnyk, P.Eng., and David Thomas, P.Geo., of AMEC Americas Limited, and Thomas L. Nimsic, RPG, of American Au Ag Associates are the Qualified Persons responsible for the preparation of the Study, they are independent of Mansfield within the meaning of section 1.4. of National Instrument 43-101, and they have reviewed and approved the technical information within this news release.

On behalf of Mansfield Minerals Inc.

Gordon P. Leask, P.Eng., CEO, President and Director

For more information please visit our website at www.mansfieldminerals.com or contact us at
(604) 681-4462.

Caution Regarding Forward-Looking Statements

Neither the TSX Venture Exchange, nor its Regulation Services Provider accepts responsibility for the adequacy or accuracy of this release.  This press release includes certain statements that may be deemed ?forward-looking statements?.  All statements in this discussion, other than statements of historical facts, that address future exploration drilling, exploration activities, anticipated metal production, internal rate of return, estimated ore grades, commencement of production estimates and projected exploration and capital expenditures (including costs and other estimates upon which such projections are based) and events or developments that the Company expects, are forward looking statements.  Although the Company believes the expectations expressed in such forward looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in forward-looking statements.  Factors that could cause actual results to differ materially from those in forward-looking statements include metal prices, exploration success, continued availability of capital and financing, and general economic, market or business conditions.  Accordingly, readers should not place undue reliance on forward-looking statements.

This news release and the information contained herein does not constitute an offer of securities for sale in the United States and securities may not be offered or sold in the United States absent registration or exemption from registration.