SOURCE: Oriental Minerals Inc.

April 27, 2007 09:00 ET

Oriental Finds 0.07% U3O8 and 0.10% Molybdenum in Chip Samples at Ogchon Uranium Project While Verification Begins on 3 Historical Uranium Deposits

VANCOUVER, BC -- (MARKET WIRE) -- April 27, 2007 -- Oriental Minerals Inc. (TSX-V: OTL) is pleased to announce initial sample geochemical results from the regional exploration program on its Ogchon Uranium Project in South Korea. Significant uranium, molybdenum and vanadium mineralization was encountered including: 0.10% Mo, 0.07% U3O8, and 0.24% V in rock chip surface samples from 11 prospective areas within the Company's 39,744 hectare application area.

The Ogchon Uranium Project encompasses a 90-kilometre trend of radiometric anomalies, as well as four historic uranium deposits (Dukpyoung, Samgoe, Soryong and Kolnami) that were previously drilled in the 1980's. Published data from the Korea Institute of Energy and Resources on these four deposits has been obtained and is being compiled and digitized. A NI-43-101 technical report updating these resource estimates has been commissioned.

The Company is currently mapping and rock chip sampling in detail in the area of these four uranium-molybdenum deposits to define targets for a planned 2007 drill program. Oriental Minerals has also been prospecting along the unconformity along which the deposits and anomalies occur, with the following results received from 24 grab rock chip samples of surface exposures from 11 different prospect areas:

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        ----------------------------------------------------------
          Element   Minimum (ppm)   Maximum (ppm)   Average (ppm)
        ----------------------------------------------------------
             U            10              744             236
        ----------------------------------------------------------
             Mo           15             1015             331
        ----------------------------------------------------------
             V            88             2430             852
        ----------------------------------------------------------
             Zn           16             4680             760
        ----------------------------------------------------------
             Cu           19              656             162
        ----------------------------------------------------------
             Ag        < 0.2                9               3
        ----------------------------------------------------------
             Ni            8             1070             174
        ----------------------------------------------------------
             P           140             2.5%            2600
        ----------------------------------------------------------

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Oriental considers the results are very significant and confirm the Ogchon Uranium Province is highly prospective for additional uranium-molybdenum-vanadium mineralization, outside of the pre-existing historical deposits. The Company applied for 144 Mining Rights in the Ogchon tectonic belt in November 2006, with formal granting of the licences expected shortly. The Mining Rights cover 39,744 hectares along a 90-kilometre-long northeast trending belt of the middle-late Ordovician Guryongsan Formation.

Some 16 airborne radiometric anomalies have been previously identified by KIGAMM and university researchers within this 90 km long belt and are related to graphitic black slate-phyllite beds of the Guryongsan Formation. An unconformity separates the Guryongsan Formation from the younger Hwanggangri Formation, which comprises calcareous pebble and pelitic phyllite.

Metallurgical studies by two South Korean universities in 2005 have shown microbacterial leaching recovers 80% of the uranium from the deposits of the Ogchon Belt. For lower grade uranium deposits this may potentially be the most effective processing method. Uranium minerals identified consist of uraninite, autunite, and meta-torbernite and occur together with phosphorite minerals, vanadium, barium, zircon, hematite, pyrite, pyrrhotite, molybdenite, nickel, lead, and chromium.

Note: Samples are grab rock chip samples and were submitted to ALS Chemex laboratory in Brisbane, Australia and analyzed by methods PGM-MS23, ME-XRF05 and ME-ICP41s.

QUALIFIED PERSON

The qualified person for the purposes of this release is Mr. Mark Dugmore.

On behalf of the Board of Directors,
Damien Reynolds
Chairman and Director
Statements in this news release, other than purely historical information, including statements relating to the Company's future plans and objectives or expected results, constitute Forward-looking statements. Such statements are based on numerous assumptions and are subject to all the risks and uncertainties inherent in the Company's business, including risks related to mineral exploration and development. Consequently, actual results may vary materially from those described in the forward-looking statements.

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

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