Orosur Mining Inc Announces Results of the Feasibility Study
For Arenal Deeps in Uruguay

MONTEVIDEO, Uruguay 07 September, 2010. Orosur Mining Inc. (�OMI� or �the Company�) (TSX-V: OMI) (AIM: OMI), a South American-focused gold producer and explorer announces the results of the Arenal Deeps Feasibility Study (�FS�).   The study was completed by AMEC E&C Services Inc. (�AMEC�)

Highlights of the Report

The financial results indicated a six-year mine life, with an IRR of 32.3%.  The gold price assumption for the FS was a constant gold price of US$1,000/oz.  No other metals were considered payable. 

The FS envisages two underground mining methods, inclined room-and-pillar (IRP) and transverse stoping (TS), based on probable mineral reserves, (effective date 1 June 2010), as follows: 

Notes to accompany Mineral Reserve Table:

1.       Underground Mineral Reserves are confined to designed stopes;

2.       A cut-off grade of 1.3 g/t Au is used for the TS, and 1.5 g/t Au for the IRP;

3.       Mineral Reserves are reported using a gold price of USD850/oz;

4.       Tonnages and ounces are rounded to the nearest 1,000 tonnes, grades are rounded to two decimal places;

5.       Tonnage and grade measurements are in metric units, ounces are troy ounces

David Fowler, CEO of the Company commented: "This feasibility study for Arenal Deeps is an important step for the Company in our objective to extend the San Gregorio mine life in Uruguay while maintaining production levels at approximately 50-60,000 ounces of gold per annum. The initial investment in capital and skills will also allow additional underground reserves to be targeted at San Gregorio to further extend mine life. Tenders for contract mining and equipment purchases are being progressed with Board approval to be considered in coming months. Funding for the project is expected to be generated from operating cash flow, which has been enhanced in this current gold price environment, and debt.�

Background
Arenal Deeps is the down plunge continuation of the Arenal deposit that waste mined as an open pit between October 2004 and April 2009 and produced 388,000 ounces of gold at an average grade of 2.16 g/t Au using a 0.5 g/t Au cut off grade.    

The mineral resource at Arenal Deeps was modeled and estimated by Mine Development Associates (�MDA�) with a result, which was announced in March 2010, of a mineral resource estimate of 2.05 Mt at 3.68 g/t Au (using a 1.5 g/t cut-off) as a base case.  MDA also prepared a range of alternative estimates, using various gold cut-off grades. AMEC reviewed and accepted the mineral resource estimate, and restated it at 1 g/t Au cut-off, effective 15 March 2010, for the purposes of the base case mineral resources for the FS, as follows:

Notes to Accompany Mineral Resources Table:
1.     Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
2.     Mineral Resources are inclusive of Mineral Reserves.
3.     Mineral Resources are reported at a cut-off grade of 1 g/t Au.
4.     Mineral Resources are reported as undiluted.
5.     Mineral Resources are reported within a conceptual pit shell.
6.     Mineral Resources are reported using a long-term gold price of USD890/oz.

Next steps

The company expects to have a 43-101 compliant mineral resource/mineral reserve for silver contained within the gold estimates completed in October 2010. Infill drilling planned in the FS is also expected to identify additional mineralization that could support conversion to mineral resources, and eventually to mineral reserves.

The Company submitted a request for environmental approval for the Arenal Deeps project on April 30, 2010 and is in the process of obtaining the environmental approvals for the project from DINAMA, the relevant authority in Uruguay.  Funding for the project is expected to come from cash from operations, enhanced in this current gold price environment, and debt.  The Board will consider the approval of the Arenal Deeps project in the coming months.

Qualified Person's Statement

The information presented in this press release has been reviewed by Mr. Randall Corbett, General Manager, San Gregorio, and is considered to be in compliance with NI 43-101 reporting guidelines. Mr. Corbett has a Bachelor of Engineering (Mining) Degree from Technical University of Nova Scotia (T.U.N.S.), is a Professional Engineer (P. Eng.) registered in the Province of Ontario and has more than 25 years operational, engineering and development experience.

The Qualified Person (QP) for the mineral resource estimate is Mr Mark Hertel, P.Geo.  Mr John Barber, P.E. is the Qualified Person for the mineral reserve estimates.  Mr Hertel and Mr Barber are AMEC employees, and are independent of the Company as within the meaning of NI 43-101. 

Forward-Looking Statements

All statements, other than statements of historical fact, contained or incorporated by reference in this news release, including any information as to the future financial or operating performance of the Company, constitute "forward-looking statements" within the meaning of certain securities laws, including the "safe harbour" provisions of the Securities Act (Ontario) and the United States Private Securities Litigation Reform Act of 1995 and are based on expectations estimates and projections as of the date of this news release. There can be no assurance that such statements will prove to be accurate; such statements are subject to significant risks and uncertainties, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements include, without limitation success of exploration activities; permitting time lines; the failure of plant; equipment or processes to operate as anticipated; accidents; labour disputes; requirements for additional capital title disputes or claims and limitations on insurance coverage. The Company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events and such forward-looking statements, except to the extent required by applicable law.

ENDS

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

About Orosur Mining Inc. 

Orosur Mining Inc. is a fully integrated gold producer and exploration company focused on identifying and developing gold projects in Latin America. The Company operates the only producing gold mine in Uruguay (San Gregorio), and has assembled an exploration portfolio of high quality assets in Uruguay and Chile. The Company is quoted in Canada (TSX-Venture Exchange: OMI) and London (AIM: OMI).

For further information, please contact:

Orosur Mining Inc
David Fowler, CEO
Ignacio Salazar, CFO  + 598 2601 6354; info@orosur.ca

Matrix Corporate Capital LLP (Nominated Adviser & Broker)
Louis Castro, +44 (0) 203 206 7209
Tim Graham, +44 (0) 203 206 7206

Blythe Weigh Communications (Public Relations and Investor Relations)
Tim Blythe: +44 (0) 7816 924626
Ana Ribeiro: +44 (0) 7980 321505
Matthew Neal: +44 (0) 7917 800011