Oro Silver Resources Ltd.
TSX VENTURE : OSR

Oro Silver Resources Ltd.

September 18, 2008 09:30 ET

Oro Silver Reports First Resource Estimate on Its El Compas Mine Property, Zacatecas, Mexico

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 18, 2008) - Oro Silver Resources Ltd. ("Oro Silver") (TSX VENTURE:OSR) announces completion of a National Instrument 43-101 compliant mineral resource estimate for its 51% owned El Compas mine property, located in Zacatecas, Mexico. This resource reported at a 3.0 g/t gold-equivalent cut-off relates to two vein zones identified on the property located at surface, namely the El Compas and El Orito veins. The mineral resource estimation follows a 5,400 metre drill campaign completed by Oro Silver in April 2008.

Mineral Resources

The indicated portion of the resource is estimated at 310,000 tonnes grading 6.52 g/t gold-equivalent for a total of 65,000 gold-equivalent ounces, while the inferred portion is estimated at 234,000 tonnes grading 5.48 g/t gold-equivalent for a total of 41,200 gold-equivalent ounces; both categories were calculated using a 3.0 g/t gold-equivalent cut-off.



Mineral Resource (1) at a 3.0 g/t Gold-Equivalent Cut-Off
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Gold- Gold-
Equiv- Equiv-
alent alent
Gold Silver Grade Gold Silver Content
Classifi- Tonnage Grade Grade (2) Content Content (2)
cation (tonnes) (g/t) (g/t) (g/t) (ounces) (ounces) (ounces)
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Indicated 310,000 5.82 59.09 6.52 58,000 588,900 65,000
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Inferred 234,000 4.94 45.69 5.48 37,200 343,700 41,200
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(1) The mineral resource is effective as of September 16, 2008.
(2) A gold equivalency factor of 83.7 was used for the silver grades. This
factor is based on gold and silver metal prices calculated from a
combination of a 36 month trailing average of the metal price (60%)
and a 24 month average of futures metal price (40%). The metal prices
used in the calculation of the gold equivalency factor are $752.30 USD
for gold and $13.38 USD for silver. The factor also incorporates gold
and silver metal recoveries of 94.5% and 63.5% respectively
(metallurgical testing done by Oro Silver Resources in 2008 - see
June 9, 2008 press release).


At a 2.0 g/t gold-equivalent cut-off, the indicated portion of the resource is estimated at 401,000 tonnes grading 5.60 g/t gold-equivalent (4.91 g/t gold and 57.89 g/t silver) for a total of 72,200 gold-equivalent ounces, while the inferred portion is estimated at 330,000 tonnes grading 4.60 g/t gold-equivalent (4.03 g/t gold and 47.16 g/t silver) for a total of 48,800 gold-equivalent ounces. Using a lower cut-off of 2.0 g/t represents an increase of 11% in the indicated resource and 19% in the inferred resource.

The indicated resources are within the El Compas vein in areas of greater drill density. The inferred resources are from both the El Compas and El Orito veins, which respectively contain 86% and 14% of the gold-equivalent inferred resource ounces. The average true widths are 7.2 metres for the El Compas vein and 3.3 metres for the El Orito vein.

This mineral resource estimate excludes the potential area above the first level of the historic underground workings at El Compas. The El Compas vein outcrops approximately 30 metres above this first level. The estimate also excludes the potential area around drill hole 08COM023 which intercepted the Old El Compas vein, a parallel vein structure located 100 metres in the footwall of the El Compas vein; this hole returned 8.23 g/t gold and 30.9 g/t silver over 1.1 metres (see June 9, 2008 press release).

Of a total of 57 diamond drill holes drilled on the property (11,200 metres), 48 were utilized for the estimation of the mineral resources. 32 holes were drilled during Oro Silver's 2007-08 drilling campaign and 16 holes are from a drill program completed by Minera Hochschild de Mexico in 2005. The sample intervals were composited to 1-metre lengths. Grades were capped at 25.0 g/t for gold and 300.0 g/t for silver. Gold and silver grades were interpolated into a 1 X 5 X 1 metre (X, Y, Z) block model using ordinary kriging. A search ellipsoid with variable azimuth and dip angles was used in the grade estimation process to better characterize the grade distribution within the mineralized veins.

The drilling completed to date indicates that the El Compas zone is open at depth to the north, while the El Orito zone is open to the south. The mineralized veins are exposed at the surface and can be accessed via adits and ramps, as was the El Compas vein where small-scale mining took place between 2003 and 2007 (see Oro Silver's website: http://www.orosilver.com/main/?ProjectGraphics).

"We are pleased with the advances achieved at El Compas during 2008. The resource grades and vein widths exceed our expectations for both the El Compas and El Orito veins. These resources are the starting point for continued drill testing and resource additions both at depth, laterally and on at least eight additional targets on our recently expanded property package. We expect that the low-cost deal terms and potentially low-cost ounces will create significant value for our shareholders," stated Herve Thiboutot, CEO and Vice-President Exploration for Oro Silver.

"Both the grades and true widths reported in the resource estimate demonstrate the potential for mining at El Compas. Our next step is to complete basic mine design, planning and cost estimation in order to generate a preliminary economic assessment with cash flow analyses," stated Tom Bagan, COO and Vice-President Operations.

Qualified Person Statement

Oro Silver's exploration programs are supervised by Herve Thiboutot, P.Eng., CEO and Vice-President Exploration of Oro Silver. Oro Silver's resource estimation was performed by Marc Jutras, M.A.Sc., P.Eng., and audited by Robert De L'Etoile, M.A.Sc., P.Eng., of SGS-Geostat. Mr. Thiboutot and Mr. Jutras are qualified persons and Mr. De L'Etoile is an independent qualified person as defined by National Instrument 43-101. Mr. Thiboutot, Mr. Jutras and Mr. De L'Etoile have reviewed and approved the information of a scientific or technical nature contained in this press release. The National Instrument 43-101 resource estimate will be available on SEDAR within 45 days of the date of this news release.

Quality control

Oro Silver maintains a strict quality control program. All sample results generated by Oro Silver and used in the resource estimation were submitted directly to Inspectorate de Mexico, S.A. de C.V., for preparation in Mexico, and analysis in Reno, Nevada. Analysis was conducted on 2 assay-ton samples, with standards and blanks inserted every 30 samples. Analysis of gold was by fire assay, with a gravimetric finish on samples exceeding 3 g/t gold. Analysis of silver was by atomic absorption, with a gravimetric finish on samples exceeding 200 g/t silver. Triple acid digestion was used on all samples. Drill results by Minera Hochschild in 2005 were made National Instrument 43-101 compliant for resource estimation purposes by quarter sawing and submitting 10% of the drill core for analysis. Assay results for 466 underground channel samples were not utilized in the resource estimate; however, the results were utilized to categorize resource material within the sample area of influence as indicated.

About Oro Silver

Oro Silver is a silver exploration company pursuing early to advanced stage silver-based opportunities primarily in the western hemisphere. The company is focused on (i) developing resources at its Vetagrande and El Compas Mine projects in Zacatecas; (ii) optimizing milling processes at its Vetagrande Mine projects; (iii) complete additional strategic acquisitions in the Zacatecas district. Oro Silver's strategy is to become a mid-tier silver producer through an aggressive acquisition and development plan focused on advanced-stage projects with known silver resources that exhibit potential for expansion.

ON BEHALF OF THE BOARD OF DIRECTORS,

Herve Thiboutot, Chief Executive Officer

Some statements in this release may contain forward-looking information. These statements include, but are not limited to, statements with respect to future exploration, resource estimation, development and production activities and future expenditures. These statements address future events and conditions and, as such, involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the statements. Such factors include, among others, the time and success of future exploration, development and production activities and the timing and amount of expenditures.

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

Contact Information

  • Oro Silver Resources Ltd.
    Herve Thiboutot
    Chief Executive Officer
    (604) 646-1588
    (604) 642-2411 (FAX)
    Website: www.orosilver.com