June 04, 2008 ORIENTALS DRILLING CONFIRMS DEPTH AND EXTENSIONS OF THE SANGDONG RESOURCE Vancouver, BC, June 4th, 2008 -- Oriental Minerals Inc. (OTL:TSX-V) is pleased to announce further results from an additional 8 holes from the drill program at the Sangdong Tungsten-Molybdenum project in South Korea. The Company continues to advance the technical studies to be incorporated into the Preliminary Economic Assessment (on-track for release before September 30, 2008) and subsequent feasibility studies. Hole SD-40 has 2 intersections reported of greater than 20 metres. Of significance is hole SD-42 which is open at depth and confirms the down dip extension of both tungsten and molybdenum mineralization at Sangdong, with an intersection of 72m @ 0.14% WO3 and 0.07% MoS2 Hole SD-43 has noteworthy combined intersections of tungsten and molybdenum of 109m @ 0.16% WO3 and 0.06% MoS2 and 66m @ 0.21% WO3 and 0.11% MoS2 . The many additional molybdenum intersections to the end of hole SD-43 at 700 metres have contributed to greater definition of the deep molybdenum mineralization. Hole SD-56 is encouraging and shows the layered zones of mineralization extend the known deposit to the northeast. Holes SD-57 to 59 have given more detail of the limits of mineralization on the southeast boundary, assisting the preliminary mine planning currently underway. Hole SD-60 is located where the skarn is near surface and has several intervals greater than 0.1% WO3. Technical studies underway include environmental baseline work, with 3 of 4 seasons already completed and metallurgical studies of a 600 kilogram sample are 60% complete. Pit optimization studies are being updated with these results, as is the Wardrop Engineering resource estimate (announced March 17, 2008). The details of the drill intersections, using a 0.1 WO3% Equivalent cut-off, are tabulated below: Hole From (m) To (m) Interval (m) WO3 (%) MoS2 (%) Rock Type (Formation) SD-40 29 50 21 0.22 0.05 Skarn (Myobong Slate) SD-40 55 84 29 0.27 0.05 Skarn (Myobong Slate) SD-42 196 200 4 0.10 0.01 Limestone/Breccia SD-42 246 318 72 0.14 0.07 Limestone/Breccia/Skarn, EOH SD-43 30 139 109 0.16 0.06 Breccia/Skarn (Myobong Slate) SD-43 152 218 66 0.21 0.11 Skarn (Myobong Slate) SD-43 225 244 19 0.03 0.06 Skarn / Quartzite SD-43 251 270 19 0.00 0.08 Quartzite (Jangsan) SD-43 281 295 14 0.01 0.16 Quartzite (Jangsan) SD-43 349 357 8 0.00 0.07 Quartzite (Jangsan) SD-43 445 456 11 0.01 0.07 Quartzite (Jangsan) SD-43 497 514 17 0.00 0.06 Quartzite (Jangsan) SD-43 530 542 12 0.01 0.13 Quartzite (Jangsan) SD-43 564 576 12 0.00 0.15 Quartzite (Jangsan) SD-43 610 638 28 0.01 0.12 Quartzite (Jangsan) SD-43 648 659 11 0.01 0.08 Quartzite (Jangsan) SD-43 686 691 5 0.03 0.03 Quartzite (Jangsan) SD-56 111 116 5 0.10 0.00 Skarn (Myobong Slate) SD-56 131 147 16 0.17 0.01 Skarn (Myobong Slate) SD-56 156 163 7 0.06 0.02 Skarn (Myobong Slate) SD-56 184 190 6 0.14 0.00 Skarn (Myobong Slate) SD-56 196 202 6 0.13 0.00 Skarn (Myobong Slate) SD-56 217 224 7 0.05 0.03 Skarn (Myobong Slate) SD-56 235 239 4 0.22 0.01 Skarn (Myobong Slate) SD-56 261 267 6 0.23 0.00 Skarn (Myobong Slate) SD-57 No significant intersections 0.00 0.00 SD-58 169 171 2 0.12 0.00 Skarn (Myobong Slate) SD-59 85 97 12 0.16 0.01 Skarn (Myobong Slate) SD-59 169 178 9 0.12 0.00 Skarn (Myobong Slate) SD-60 0 4 4 0.13 0.00 Overburden / Skarn SD-60 37 55 18 0.13 0.03 Skarn (Myobong Slate) SD-60 71 82 11 0.08 0.03 Skarn (Myobong Slate) SD-60 93 95 2 0.62 0.01 Skarn (Myobong Slate) SD-60 118 128 10 0.17 0.01 Skarn (Myobong Slate) SD-60 162 170 8 0.15 0.00 Skarn (Myobong Slate) SD-60 180 182 2 0.01 0.08 Quartzite (Jangsan) Current Drill Status: As at 2nd June 2008, 79 holes have been drilled for a total of over 20,000m. Currently, 4 diamond rigs are operational. The status of drilling is tabulated below. HoleID UTME(m) UTMN(m) RL(m) Azimuth True(°) Inclination(°) Depth(m) Drill Type Date Completed SD-63 485142 4111806 870 135 -70 500 Diamond 30-Apr SD-66 485473 4111384 683 315 -70 181 Diamond 25-Apr SD-67 485296 4111218 828 135 -70 161 Diamond 9-Apr SD-69 484610 4111364 928 315 -70 221 Diamond 11-Apr SD-73 485160 4111479 787 315 -70 490 Diamond 8-May SD-74 484744 4111383 850 135 -70 135 RC 3-Apr SD-75 484774 4111383 850 315 -70 90 RC 5-Apr SD-76 485380 4111661 735 315 -70 455 Diamond 12-May SD-77 484611 4111364 928 135 -70 c134 Diamond In progress SD-78 485142 4111806 870 205 -70 201 Diamond 17-May SD-79 485160 4111479 787 255 -55 109 Diamond 19-May SD-80 485095 4111255 847 135 -70 c168 Diamond In progress SD-81 484871 4111363 836 315 -70 c118 Diamond In progress SD-82 485160 4111479 787 240 -70 85 Diamond 29-May SD-83 485160 4111479 787 135 -70 c8 Diamond In progress Analytical results are awaited from the completed holes. Updated Drill Program Map To view an updated Drill Program Map, please go to www.orientalminerals.com. QA/QC Samples are 1-metre split PQ, HQ or NQ core or 1-metre split RC. The samples were prepared at the on-site preparation facility and pulps 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, Standards and Coarse and Pulp Duplicates samples were routinely inserted with the drill samples at random intervals. Blank samples were clean, indicating no cross contamination in the samples. All results confirm analysis of Standards and Coarse Duplicates are within the normal bounds of acceptable error of +/- 5%. Pulp Duplicate samples processed by another independent laboratory are also within the normal bounds of acceptable error of +/- 5%.
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