Orosur Mining Inc. announces results for update...

Orosur Mining Inc. announces results for updated resource estimate of Arenal Deeps of 2.05Mt @ 3.68g/t (using a 1.5g/t cutoff)

Orosur Mining Inc.

Orosur Mining Inc. (“OMI” or the “Company”) is pleased to announce completion of the updated Arenal Deeps resource estimate. The resource was modeled and estimated by Mine Development Associates and is considered to be NI 43-101 compliant. A summary table is presented here and more information can be found on the company web site. The 1.5 Au g/t cutoff is highlighted as the current anticipated economic cutoff based on a prefeasibility study produced by Golders & Associates dated 24 September 2009.

Measured												Â	Â	Â	Indicated													Â	Â
Cutoff	Â	Â	Tonnes	Â	Â	Â	Grade	Â	Â	Â	Gold				Cutoff	Â	Â	Â	Tonnes	Â	Â	Â	Grade	Â	Â	Â	Gold
Â			Â				(g Au/t)				Ounces				Â				Â				(g Au/t)				Ounces
0.5			3,089,000				1.57				155,000				0.5				5,987,000				1.45				280,000
1.0			1,416,000				2.59				118,000				1.0				2,587,000				2.44				203,000
1.5			846,000				3.52				96,000				1.5				1,297,000				3.68				153,000
2.0			586,000				4.33				82,000				2.0				908,000				4.52				132,000
Measured and Indicated															Inferred
0.5			9,076,000				1.49				435,000				0.5				162,000				2.01				10,000
1.0			4,002,000				2.49				321,000				1.0				99,000				2.84				9,000
1.5			2,143,000				3.61				249,000				1.5				63,000				3.77				8,000
2.0			1,494,000				4.43				213,000				2.0				44,000				4.65				7,000
Note: as of end of July 2009 topography

Arenal Deeps is the down plunge continuation of the Arenal deposit that was 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 Au g/t using a 0.5g/t cut off grade.

The Arenal Deeps exploration and resource definition drilling programs completed 108 RC and diamond drill holes for 34,454 meters during 2008 and 2009. 62% of the holes were diamond and 38% RC and RC pre-collars. The drill programs were based on 25m spaced N-S sections and an attempt was made to keep the drill hole spacing to less than 50m along section resulting in a drill density of approximately 25m x 50m. The deposit is fault-bounded to the west but considered to be still open along strike to the east and down plunge to the SE.

As announced on 25 February 2010 AMEC has been appointed to complete a feasibility study and have already visited the San Gregorio Mine site to commence this work which is expected to be completed in the third calendar quarter of 2010.

David Fowler, Chief Executive Officer commented: “We are pleased with the updated resource estimate for Arenal Deeps and that it has resulted in an increase in measured and indicated grade, from 2.21 Au g/t in the previous resource estimate to 3.61 Au g/t in this estimate assuming a 1.5 Au g/t cutoff. While tonnes are lower than the previous resource estimate overall ounces have increased and the increase in grade will improve project economics. The OMI technical team at San Gregorio did a great job on delivering the model on time and the results are better than expected.”

Qualified Person's Statement

The information presented in this press release has been reviewed by Devin den Boer, PGeo, OMI Exploration Manager and is considered to be in compliance with NI 43-101 reporting guidelines. Mr. den Boer has a Bachelor of Science (Geological Sciences) Degree from the University of British Columbia, is a registered member of APEGBC and has over 13 years of international experience in minerals exploration.

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.

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:David Fowler, CEO:
Ignacio Salazar, CFO + 598 2 6016354; Ignacio Salazar, CFO + 598 2 6016354; [e-mail]

Matrix Corporate Capital LLP (Nominated Adviser & Broker)
Louis Castro, [phone]Louis Castro, [phone]
Tim Graham, [phone]Tim Graham, [phone]

In North America
Forbes West 416-203-2200Forbes West [e-mail]