Mansfield Minerals Inc.: Lindero Gold Project Moves Towards Pre-Feasibility.

VANCOUVER, British Columbia -- Mansfield Minerals Inc. (the "Company") (TSX VENTURE:MDR) is pleased to announce the results of metallurgical testwork completed on its Lindero gold project, Salta Province northwestern Argentina where an inferred resource of 29,953,000 tonnes at 1.08 grams/ton gold (1,035,900 oz gold) using a 0.6 gram/tonne cut-off was estimated by Rio Tinto Mining and Exploration Ltd., audited by Roscoe Postle Associates Inc., and announced in our September 22, 2003 news release. Sampling for the current testwork was executed by American Au-Ag Associates, with laboratory analysis completed by Kappes, Cassiday and Associates ("KCA"), an international metallurgical and analytical consulting firm, both of Reno, Nevada.

Three types of mineralized material were sampled and included 30 samples totaling 77.94 kilograms from oxide material in surface trenches, 13 samples totaling 72.48 kilograms from oxide drill core, and 20 samples totaling 112.30 kilograms from hypogene/sulphide drill core. Thirteen bottle roll tests were run on three composites using a 6.3mm (1/4"), 12.5mm (1/2"), and 19mm (3/4") crush. In addition, two column tests were run on sulphide/hypogene core, 19mm (3/4") and 12.5mm (1/2"), respectively, and one column test was run on oxide trench material crushed to (12.5mm) 1/2". The results of the bottle roll and column metallurgical testing show that:

1. Lindero mineralization is amenable to extraction of gold using cyanide;

2. In the tests, approximately 70% of the gold was recovered in 100 days. With long term leaching in the field recoveries should be expected to be somewhat more than the tests as the columns were still recovering slowly at 101 days;

3. NaCN consumption will be approximately 0.6 kg/tonne;

4. Caustic lime consumption will be in the range of 1.25 kg/tonne; and

5. The optimal crush size range is between 12.5mm (1/2") and 19mm (3/4").

Thomas L. Nimsic of American Au-Ag Associates states "The testwork undertaken by Kappes, Cassiday & Associates under the supervision of myself is very positive. The recommendations are for additional drilling to further delineate and define the resource in conjunction with undertaking a pre-feasibility study which would encompass further metallurgical testing using large diameter columns and determining reasonable assumptions for technical, engineering, operating and economic factors in sufficient detail that a Qualified Person, acting reasonably, may determine that the mineral resource may be classified as a mineral reserve."

In addition, there appears to be substantial amounts of +0.4 grams/tonne gold mineralization at Lindero that is not included in resource estimates. With more comprehensive costing, part of this mineralization may be included in future resource estimates.

A positive outcome from the pre-feasibility study would lead to a full feasibility study which, in the opinion of a Qualified Person, could reasonably serve as the basis for a decision by an independent commercial financial institution to finance the development of the Lindero property for commercial production.

On the basis of the foregoing recommendations and, given the favourable location, access and infrastructure, the Company intends to commence a 3,000 metre drill program in early 2005. The commencement date of the program is contingent upon securing a drill contractor. Upon acquiring sufficient drill core, the Company will make arrangements to set up the large diameter column testing and initiate the pre-feasibility study.

Security - Chain of Custody

The trench samples were bagged in the field as they were chipped. The bags were tied with plastic colour-coded security ties. The cores were broken to 7.5cm pieces, placed in bags and tied with colour-coded plastic ties. American Au-Ag Associates were with the samples at all times, except during the night. At night, the samples were photographed and locked up. In the morning, the sample bags were examined for signs of tampering. The sample bags were placed in shipping boxes, taped up and delivered to the Airlines courier for delivery to KCA. The samples were received by KCA in good order with the security tags utilized by Mr. Nimsic in place. All testwork was completed utilizing methods accepted by the mining industry for the examination of gold and silver deposits. The QP for this testwork is Daniel W. Kappes, President of KCA. All head assays were run as one assay ton fire assays. The tailings from all the tests were run as two assay ton fire assays. Both Florin Analytical Services LLC and ALS Chemex ran the one ton assays. Florin Analytical Services LLC and ALS Chemex are reputable analytical laboratories with rigorous QA/QC protocol and procedures.

For the purpose of National Instrument 43-101, the QP and supervisor of this project was Thomas L. Nimsic, Professional Geologist No. 1414, State of Arkansas.

On behalf of the Board of Directors,

Gordon P. Leask, P.Eng., President

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