SOURCE: Oriental Minerals Inc.

April 04, 2007 08:30 ET

Oriental Hits More Molybdenum and Tungsten Mineralization at Sangdong

VANCOUVER, BC -- (MARKET WIRE) -- April 4, 2007 -- Oriental Minerals Inc. (TSX-V: OTL) is very pleased to announce the remaining drill results received from the Company's first drill hole at the Sangdong tungsten-molybdenum project in South Korea. SD-01 was designed to drill test the entire 165-metre thick skarn package (145m - 309m), above and below the 6-metre main vein historically mined by Korea Tungsten Co. Ltd., for bulk mining potential and to drill test the historical molybdenum resource underneath the skarn (309m - 781m). Remaining results from the 165-metre thick skarn package include:

* 6 metres grading 0.09% tungsten trioxide and 0.14% molybdenum
* 6 metres grading 0.27% tungsten trioxide and 0.02% molybdenum
* 10 metres grading 0.14% tungsten trioxide
Molybdenum intervals below the skarn include:
* 11 metres grading 0.15% molybdenum
* 8 metres grading 0.16% molybdenum
* 5 metres grading 0.18% molybdenum
SD-01 bottomed in molybdenum mineralization, with the lower 463 metres averaging 0.053% Mo. Two additional drill rigs are due to arrive on site shortly to help finish Phase 1 and begin Phase 2 drilling. Phase 2 involves 67 holes drilled at 100 x 100 metre spacing, with 24 of those holes targeting the historic deep molybdenum zone.

Significant results from the lower portion of hole SD-01 are tabulated below:

===========================================================================
Intersection  Depth     WO3(%) Mo(%)   MoS2(%)      Formation
 Thickness
---------------------------------------------------------------------------
12 metres    212-224m   0.08   0.09     0.15    Skarn altered Myobong Slate
---------------------------------------------------------------------------
 6 metres    228-234m   0.09   0.14     0.23    Skarn altered Myobong Slate
---------------------------------------------------------------------------
 3 metres    244-247m   0.11   0.10     0.17    Skarn altered Myobong Slate
---------------------------------------------------------------------------
 5 metres    247-252m                           Void. Main Vein stope
                                                workings.
---------------------------------------------------------------------------
 6 metres    252-258m   0.27   0.02     0.03    Skarn altered Myobong Slate
---------------------------------------------------------------------------
 3 metres    260-263m   0.16    -        -      Skarn altered Myobong Slate
---------------------------------------------------------------------------
 7 metres    271-278m   0.11   0.06     0.11    Skarn altered Myobong Slate
---------------------------------------------------------------------------
 10 metres   287-297m   0.14   0.03     0.05    Skarn altered Myobong Slate
---------------------------------------------------------------------------
  1 metre    308-309m   0.15    -        -      Skarn altered Myobong Slate
---------------------------------------------------------------------------
  4 metres   318-322m    -     0.11     0.18    Jangsan Quartzite
---------------------------------------------------------------------------
  3 metres   339-342m    -     0.11     0.18    Jangsan Quartzite
---------------------------------------------------------------------------
  8 metres   360-368m    -     0.15     0.25    Jangsan Quartzite
---------------------------------------------------------------------------
  2 metres   375-377m    -     0.10     0.17    Jangsan Quartzite
---------------------------------------------------------------------------
  4 metres   391-395m    -     0.12     0.20    Jangsan Quartzite
---------------------------------------------------------------------------
  3 metres   437-440m   0.01   0.10     0.17    Jangsan Quartzite
---------------------------------------------------------------------------
  8 metres   468-476m    -     0.16     0.27    Jangsan Quartzite
---------------------------------------------------------------------------
  5 metres   487-492m    -     0.14     0.23    Jangsan Quartzite
---------------------------------------------------------------------------
  5 metres   505-510m    -     0.18     0.30    Jangsan Quartzite
---------------------------------------------------------------------------
  3 metres   571-574m    -     0.12     0.20    Jangsan Quartzite
---------------------------------------------------------------------------
  4 metres   576-580m    -     0.10     0.17    Jangsan Quartzite
---------------------------------------------------------------------------
  6 metres   580-586m    -     0.06     0.10    Jangsan Quartzite
---------------------------------------------------------------------------
  9 metres   612-621m    -     0.15     0.25    Jangsan Quartzite
---------------------------------------------------------------------------
  8 metres   626-634m    -     0.15     0.25    Jangsan Quartzite
---------------------------------------------------------------------------
  3 metres   640-643m    -     0.11     0.18    Jangsan Quartzite
---------------------------------------------------------------------------
 11 metres   653-664m    -     0.15     0.25    Jangsan Quartzite
---------------------------------------------------------------------------
 11 metres   668-679m    -     0.09     0.15    Jangsan Quartzite
---------------------------------------------------------------------------
  4 metres   693-697m    -     0.12     0.20    Jangsan Quartzite
---------------------------------------------------------------------------
  1 metre    704-705m    -     0.13     0.22    Jangsan Quartzite
---------------------------------------------------------------------------
  4 metres   710-714m    -     0.12     0.20    Jangsan Quartzite
---------------------------------------------------------------------------
  1 metre    734-735m    -     0.18     0.30    Jangsan Quartzite
---------------------------------------------------------------------------
  1 metre    769-770m    -   > 1.00   > 1.67    Jangsan Quartzite
---------------------------------------------------------------------------
  1 metre    779-780m    0.25    -        -     Jangsan Quartzite
===========================================================================
These results indicate tungsten-molybdenum mineralization is disseminated much more broadly than reported historically and with highly significant grades occurring almost 70 metres closer to surface than the old tungsten mine workings. This has very important implications, both in terms of the amount of mineralization and the choice of a future mining method.

Drilling operations continue at Sangdong, with hole SD-02 currently at 202 metres depth and targeted to 640 metres. Drill hole SD-03 has just completed at 360 metres depth. A third diamond drill rig has commenced hole SD-04 and is currently at 45 metres and is targeted to 225 metres depth. Furthermore, the two additional drill rigs and ancillary support equipment will arrive shortly on site from Australia.

A large void was intersected between 248.3m and 250.6m. It is believed the void represents the Main Vein previously mined by Korean Tungsten Co. Ltd during 1947-1992. Detailed mine plans suggest approximately 30% of the Main Vein was left behind as roof pillar support. A historical resource was reported by KORES to be estimated at 15.6 million tonnes at 0.5% WO3 in the 6-metre thick Main Vein ore body ("remnant ore reserve"). Drill results from SD-01 indicate the presence of a considerably larger major mineralized skarn package that is 165 metres thick (145-309m). Note that a qualified person has not done sufficient work to classify these historical "reserves" as current mineral "reserves." The issuer is not treating the historical estimates as current mineral resources and the historical estimates should not be relied upon. As the historically reported "reserve" is not yet accompanied by operating permits or positive economic modeling, the estimate should be considered as a historical resource.

Widespread disseminated molybdenum mineralization has been intersected below the skarn package within the Jangsan Quartzite. This mineralization is associated with narrow bedding concordant quartz-molybdenite veins with occasional sub-vertical vein structures. Drill hole SD-01 has confirmed that a major molybdenum mineralized system is clearly present at the Sangdong mine.

Previous underground drilling (22 diamond drill holes) by Korean Tungsten Co., Ltd and KORES discovered the deep molybdenum deposit beneath the tungsten mine workings. This deep molybdenum deposit has a historical resource of 120 million tonnes grading 0.129% MoS2 with a higher-grade part of the deposit of 16 million tonnes grading 0.4% MoS2. A qualified person has not done sufficient work to classify this historical resource as current mineral resources. The issuer is not treating the historical estimate as current mineral resources and the historical estimates should not be relied upon. These estimates are also subject to independent confirmation as to whether categorization is NI 43-101 compliant.

The mineralized intersections hosted in the skarn altered Myobong Slate closely correlate with bedding concordant quartz-scheelite veins and as such represent near true width intersections. They follow on from the previously reported (2 March, 2007) high grade intersections down to 212 metres.

SD-01 intersected the following lithological units in sequence:

0-144m. Pungchon Limestone.
144-182m. Basal sedimentary breccia of the Pungchon Limestone. Minor quartz-
scheelite vein stockwork.
182-309.6m. Quartz-scheelite vein stockworks in skarn altered Myobong
Slate.
309.6-417m. Jangsan Quartzite with quartz-molybdenum vein stockwork.
417-435m. Intense brecciated Jangsan Quartzite with quartz-molybdenum vein
stockwork.
435-459m. Jangsan Quartzite with quartz-molybdenum vein stockwork.
459-541m. Intense brecciated Jangsan Quartzite with quartz-molybdenum vein
stockwork.
541-692.5m. Jangsan Quartzite with quartz-molybdenum vein stockwork.
692.5-781m. Taebeksan Series schist with quartz-molybdenum vein stockwork.
Note: Samples are 1-metre split HQ core samples and were submitted to ALS Chemex laboratory in Brisbane, Australia and analyzed by Ore Grade Method XRF-ME05, Au-AA21, ME-ICP41s and Ag-OG46. Quality Control: Blanks and Standards samples were routinely inserted with the drill samples at random intervals. Analysis of Standards indicates the laboratory results are all within +/-5% of certified assays and so results are considered reliable. Blank samples were clean, indicating no cross contamination in the samples.

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.

Contact Information