Pacific Rim Mining Corp.
AMEX : PMU
TSX : PMU

Pacific Rim Mining Corp.

March 06, 2007 09:15 ET

Pacific Rim Mining's High Grade Balsamo Gold Discovery Continues to Grow

VANCOUVER, BRITISH COLUMBIA--(CCNMatthews - March 6, 2007) - Exploration drilling at Pacific Rim Mining Corp.'s ("Pacific Rim" or "the Company") (TSX:PMU)(AMEX:PMU) El Dorado gold project in El Salvador has yielded further bonanza gold grades and expanded the dimensions of the recently discovered Balsamo gold zone, where drill hole P06-522 intersected 32.3 g/t gold over 3.9 meters. A complete list of the most recent drill results is provided below.

The Balsamo discovery has quickly evolved into an exciting and potentially significant new gold zone, owing to its high grade, wide vein widths, growing dimension and proximity to planned infrastructure. With the latest results presented below, the Balsamo zone has now been intersected over a strike length of 250 meters and a vertical range of over 150 meters and remains open along strike and to depth. Four drills are being employed at Balsamo to expand the gold zone as quickly as possible. A fifth drill rig is being mobilized.

Balsamo has the potential to significantly increase the high grade gold resource at El Dorado and enhance the project's economic landscape. The Company has therefore deferred its El Dorado feasibility study in order to realize the economic benefit of the Balsamo deposit. The underground access tunnel will take a year and a half to complete, once permits are in hand, providing the Company ample time to determine the economic impact of the Balsamo deposit in parallel with development.

"The high grade Balsamo discovery is the most exciting thing to happen to the El Dorado project since the discovery of Minita," says Tom Shrake, President and CEO of Pacific Rim. "The Balsamo vein represents a new gold-enriched structure similar to the prolific Minita structure where the bulk of the El Dorado resources and reserves occur, and has the potential, like Minita, to host multiple deposits. The Balsamo deposit will potentially increase production levels at the proposed El Dorado operation without substantially delaying the development of the property. All of the Company's resources are focused on the advancement and inclusion of this exciting discovery."



Latest El Dorado Project Drill Results

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Drill
hole
UTM azi- From To Inter- True
Vein North- muth/ (met- (met- sec- Wid-
or ing/ dip ers ers tion th Sil-
Hole System East- (degr- down down (met- (met- Gold ver
No. Tested ing ees) hole) hole) ers) ers) (g/t) (g/t)
-------------------------------------------------------------------------
P06-510 Condem- 300488/ 270/
nation 535148 50 377.55 379.55 2.00 2.00 12.253 119
-------------------------------------------------------------------------
P06-511 Moreno 301927/ 073/
534300 50 No Significant Results
-------------------------------------------------------------------------
P06-512 Nueva
Esperanza- 302468/ 068/
Los Jobos 534243 50 174.25 175.30 1.05 0.85 13.229 177
-------------------------------------------------------------------------
P06-513 Nueva
Esperanza- 302576/ 106/
Los Jobos 534164 65 89.50 91.40 1.90 1.70 9.279 52
-------------------------------------------------------------------------
P06-515 Nueva
Esperanza- 302663/ 100/
Los Jobos 534266 56 182.50 182.70 0.20 0.20 11.806 645
-------------------------------------------------------------------------
183.45 183.95 0.50 0.30 9.190 156
-------------------------------------------------------------------------
P06-516 Moreno 301910/ 105/
534301 52 253.25 258.50 5.25 2.50 8.919 30
-------------------------------------------------------------------------
P06-517 Nueva
Esperanza- 302755/ 115/
Los Jobos 534280 65 228.85 229.40 0.55 0.50 24.499 189
-------------------------------------------------------------------------
P06-518 Condem- 300184/ 270/
nation 535218 50 No Significant Results
-------------------------------------------------------------------------
P06-519 Nueva
Esperanza- 302798/ 75/
Los Jobos 534365 50 132.40 133.75 1.35 1.35 10.477 61
-------------------------------------------------------------------------
includes 132.40 132.95 0.55 0.55 20.369 138
-------------------------------------------------------------------------
P06-520 Nueva
Esperanza- 302662/ 82/
Los Jobos 534270 50 183.75 184.90 1.15 1.15 7.560 155
-------------------------------------------------------------------------
includes 184.60 184.90 0.30 0.30 19.172
-------------------------------------------------------------------------
P06-521 Moreno 301908/ 125/
534299 60 No Significant Results
-------------------------------------------------------------------------
P06-522 Balsamo 300212/ 250/
534851 48 333.90 337.90 4.00 3.90 32.271 69
-------------------------------------------------------------------------
P07-523 Condem- 300463/ 95/
nation 534599 52 No Significant Results
-------------------------------------------------------------------------
P07-524 Moreno 302407/ 93/
534626 50 No Significant Results
-------------------------------------------------------------------------
P07-525 Los 302758/ 80/
Jobos 534283 55 219.25 219.95 0.70 0.60 8.246
-------------------------------------------------------------------------
P07-526 Los 302592/ 90/
Jobos 534243 50 No Significant Results
-------------------------------------------------------------------------
P07-527 Moreno 302493/ 93/
534644 50 No Significant Results
-------------------------------------------------------------------------
P07-528 Condem- 300175/ 88/
nation 534434 47 No Significant Results
-------------------------------------------------------------------------
P07-529 Balsamo 300096/ 262/
534954 50 397.45 401.25 2.45 2.30 8.070
-------------------------------------------------------------------------
P07-530 Los 302799/ 90/
Jobos 534365 75 No Significant Results
-------------------------------------------------------------------------
P07-531 Moreno 302565/ 90/
534676 50 No Significant Results
-------------------------------------------------------------------------
P07-532 Balsamo 300175/ 71/
534434 50 360.15 360.3 7.15 4.00 10.710
-------------------------------------------------------------------------
includes 362.85 367.3 4.45 2.20 14.800
-------------------------------------------------------------------------
379.30 384.8 5.5 1.75 20.590
-------------------------------------------------------------------------
P07-533 Balsamo 300275/ 270/
534828 50 307.35 307.75 0.4 0.20 9.520
-------------------------------------------------------------------------
P07-534 Nueva
Esperanza- 302874/ 90/
Los Jobos 534319 50 217.75 218.1 0.35 0.30 7.000
-------------------------------------------------------------------------
P07-535 Morano 302407/ 110/
534626 65 No Significant Results
-------------------------------------------------------------------------
P07-536 Balsamo 300075/ 259/
534760 62 245.05 245.15 0.1 0.10 8.520
-------------------------------------------------------------------------
P07-537 Balsamo 3000275/ 270/
534828 60 336.55 338.95 2.4 1.90 11.450
-------------------------------------------------------------------------
P07-538 Moreno 302407/ 82/
534626 60 No Significant Results
-------------------------------------------------------------------------
P07-539 Nueva
Esperanza- 302960/ 90/
Los Jobos 534390 50 No Significant Results
-------------------------------------------------------------------------


Readers are directed to the Company's website www.pacrim-mining.com and SEDAR filings www.sedar.com for complete drill results from the El Dorado project, details of the El Dorado resource and reserve calculations, and complete National Instrument 43-101 disclosure.

About Pacific Rim Mining Corp.

Pacific Rim is a growth-oriented, revenue-generating, environmentally and socially responsible gold exploration company with operational and exploration assets in North, Central and South America. The Company is expanding and developing its advanced-stage, high grade El Dorado gold project in El Salvador and is actively exploring a pipeline of grassroots gold projects. Pacific Rim's goal is to become a low cost, intermediate level gold producer.

On behalf of the board of directors,

Thomas C. Shrake, President and CEO

NI 43-101 Disclosure

Pacific Rim's exploration work on the El Dorado project is supervised by William Gehlen a Certified Professional Geologist with the AIPG (No. 10626), an employee of Pacific Rim and a Qualified Person as defined in NI 43-101. Mr. Gehlen has verified that the results presented above have been accurately summarized from the official assay certificates provided to the Company. Pacific Rim's sampling procedures follow the Exploration Best Practices Guidelines outlined by the Mining Standards Task Force and adopted by The Toronto Stock Exchange. Samples have been assayed using fire assay with a gravimetric finish on a 30-gram split. Quality control measures, including check- and sample standard-assaying, are being implemented. Samples were assayed by Inspectorate America Corporation in Reno, Nevada USA, an ISO 9002 certified laboratory, independent of Pacific Rim Mining Corp.

The July 2006 El Dorado resource estimate was prepared by Mr. Steve Ristorcelli, P.Geo. of Mine Develoment Associates, Reno, Nevada. Mr. Ristorcelli is an independent Qualified Person as defined in NI 43-101. The resource estimate conforms to current CIM Standards on Mineral Resources and Reserves. A technical report in support of the updated El Dorado resource estimate presented above was filed with SEDAR on July 31, 2006. The report was co-authored by Mr. Steve Ristorcelli, P.Geo. and Mr. Peter Ronning, P.Eng., each of whom are independent Qualified Persons as defined in NI 43-101.

The January 2005 El Dorado pre-feasibility study is supported by a technical report prepared for Pacific Rim Mining Corp. by SRK Consulting (US) Inc. of Denver Colorado, entitled "Pre-Feasibility Study, El Dorado Project, El Salvador", dated January 21, 2005 and publicly available on SEDAR (www.sedar.com). The primary author of the report is Mr. William F. Tanaka, a Qualified Person independent of Pacific Rim, as defined in NI 43-101. Mr. Tanaka is a member of the Society of Mining Engineers (SME) and the Australasian Institute of Mining and Metallurgy (mAUSIMM).

Cautionary Note Regarding Forward-Looking Information

Information set forth in this document includes forward-looking statements. By their nature, forward-looking statements are subject to numerous risks and uncertainties, some of which are beyond Pacific Rim's control, including but not limited to: the timeframe and outcome of delineation of the Balsamo discovery and its potential impact on the El Dorado project; the eventual scope of the El Dorado feasibility study; the timeframe for completion of the El Dorado feasibility study; anticipated drilling plans for the El Dorado project; the nature of future results and potential for new discoveries at the El Dorado project; statements of the Minita deposit's economic potential; the timing and nature of economic analyses at the El Dorado project; the execution and outcome of current or future exploration activities; significant fluctuations in metal prices; general market and industry conditions; and other factors detailed in the Company's filings with Canadian regulatory agencies and the U.S. Securities and Exchange Commission.

Readers are cautioned that the assumptions used in the preparation of such information, although considered reasonable at the time of preparation, may prove to be imprecise and, as such, undue reliance should not be placed on forward-looking statements. Pacific Rim's actual results, programs and financial position could differ materially from those expressed in or implied by these forward-looking statements.

Cautionary Note to U.S. Investors - The United States Securities and Exchange Commission permits U.S. mining companies, in their filings with the SEC, to disclose only those mineral deposits that a company can economically and legally extract or produce. This news release may include such terms as "measured", "indicated", and "inferred" "resources" that the SEC guidelines strictly prohibit U.S. registered companies from including in their filings with the SEC. U.S. Investors are urged to consider closely the disclosure in our Form 20-F, File No. 001-31328, which may be secured from us, or from the SEC's website at www.sec.gov/edgar.shtml.

The TSX and the AMEX have neither reviewed nor accept responsibility for the adequacy or accuracy of this release.

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