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Re:   News Releases - Monday, June 04, 2012
      World Bank Tribunal Allows Pacific Rim Subsidiary to Continue to
      Final Phase in Arbitration Case against El Salvador; Official
      Decision Supports Pacific Rim's Rights to Claim Damages
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PMU News Release #12-05
TSX: PMU
OTCQX: PFRMF
June 4, 2012


World Bank Tribunal Allows Pacific Rim Subsidiary to Continue to Final
Phase in
Arbitration Case against El Salvador:
Official Decision Supports Pacific Rim's Rights to Claim Damages

Pacific Rim Mining Corp. ("Pacific Rim" or the "Company") announces
that the investment dispute of its US subsidiary PacRim Cayman, LLC
("PacRim") with the Government of El Salvador ("GOES") will proceed to
the final phase of the arbitration case.  A Tribunal at the
International Centre for Settlement of Investment Disputes ("ICSID")
has issued its ruling on "jurisdictional" objections filed by the GOES
and decided that the case will proceed under El Salvador's Foreign
Investment Law (the "Investment Law").

In this final phase of the arbitration, the merits of PacRim's claims
will finally be addressed. The Tribunal will determine whether El
Salvador has breached Salvadoran and international law by refusing to
issue the necessary mining licenses. They will also determine El
Salvador's monetary liability for breaching the investment protections
owed to a foreign investor as per in its own laws.

The Tribunal determined ICSID (at the World Bank) has jurisdiction and
will hear PacRim's claims under the Salvadoran Investment Law, but not
under the Dominican Republic-United States-Central America Free Trade
Agreement ("CAFTA").  Accordingly, the arbitration claim can and will
proceed under the Investment Law alone.  ICSID, a branch of the World
Bank, will continue to oversee this claim at its headquarters in
Washington, DC. ICSID's complete ruling is available at
http://icsid.worldbank.org/ICSID/Index.jsp.

Through its jurisdictional objections, El Salvador had sought to
terminate the arbitration. As it did in August 2010 in its ruling on
the GOES's preliminary objections, for the second time the Tribunal
thought otherwise and ruled against El Salvador. In its decision, the
Tribunal rejected the GOES's allegations that ICSID does not have
jurisdiction over PacRim's claims under the Investment Law. The
Tribunal also rejected most of the GOES's objections to the Tribunal's
CAFTA jurisdiction (including rejecting the GOES's assertion that the
case constituted an "abuse of process").  However, while ruling that
PacRim is in fact a US company and is part of a group of companies that
has substantial business activities in the United States, the Tribunal
concluded that the specific subsidiary that filed the claim does not
have sufficiently "substantial" business activities in the US to allow
the investment protections under CAFTA.

PacRim and its legal counsel will immediately begin to prepare for the
final phase of the arbitration. The Company will be exploring various
alternative financing opportunities, now more available, to help
minimize dilution to its current share structure. In this regard the
Company has received encouraging feedback from potential sources of
non-equity financing.

"We look forward to proceeding to the final portion of the arbitration
case to recover the value of the El Dorado asset," states Tom Shrake,
President and CEO. "We are very confident in the merits of this case.
The fact that it will proceed under the Investment Law alone rather
than under both sets of investment protections has no impact on the
case. What is relevant is the fact that we will continue to protect our
company's rights with ICSID, at the World Bank. It is our hope the
Government of El Salvador will put an end to this dispute and put her
people and our industry back to work. Every mining concession in El
Salvador has been expropriated, resulting in the loss of jobs, tax
revenues and stability, as well as El Salvador's standing in the
foreign investment community."

According to Arif Ali, head of international arbitration at Weil,
Gotshal & Manges and counsel for PacRim in the arbitration, "we're
extremely pleased that our strategy of pursuing PacRim's rights under
both CAFTA and the Salvadoran Investment Law paid off. Although the
Tribunal decided not to assert jurisdiction over PacRim's CAFTA claims,
it said nothing about the validity of those claims or the Company's
rights. In fact, it affirmed the Company's rights to pursue its claims
under the Salvadoran Investment Law, which contains numerous investment
protections that are very similar to those found in CAFTA."

Pac Rim is also represented in the dispute by Crowell and Moring LLP,
and R. Timothy McCrum, a partner in the law firm's Environmental and
Natural Resources Group, who added, "It is a great development that the
Tribunal has confirmed its jurisdiction over El Salvador under the
ICSID Convention. The final phase of the case will now reveal that
there is no genuine environmental controversy here, but simply a
politically motivated effort to expropriate this gold resource
discovered by extensive mineral exploration drilling at enormous
expense."

The El Dorado Mine, as designed and submitted to the Salvadoran
authorities eight years ago, would set new precedents for environmental
protection in all of the Americas and exceeds current Canadian and US
environmental standards. Preservation of water quality and quantity is
a key component the industry-leading El Dorado mine design. Water for
ore processing is to be collected in a reservoir in the subtropical
ecosystem and not drawn from local water supplies. The water used by
the operation will be extensively recycled and any water discharged
from the reservoir will be processed by a water treatment plant.  Water
leaving the reservoir will be significantly cleaner than it was when it
arrived on site and will provide a clean water source for local
villages.

Had the GOES followed their laws, the El Dorado Mine would be in
operation today, employing thousands. The Company would be the single
greatest taxpayer in El Salvador. The tremendous gold potential of El
Salvador would be further advanced and by this time, other operations
would be under development.

The Company owns, or has negotiated rights to work on all surface lands
needed by the operation. The Company has met or exceeded all the legal
requirements necessary for a mining permit according to El Salvador's
mining, environmental and foreign investment laws.


On behalf of the board of directors,
       
"Thomas C. Shrake"

Thomas C. Shrake
President and CEO

To contact the Company about this news release call 604-689-1976 or
1-888-775-7097.

Forward-Looking Information
This news release contains forward-looking statements that are subject
to a variety of risks and uncertainties, any of which could cause
actual events or results to differ from those reflected in the
forward-looking statements, including, without limitation: risks
related to the outcome of these legal proceedings; risks related to
financing; risks related to development of mining operations in El
Salvador and the economic impact of those operations; environmental
risks; and other risks and uncertainties related to the Company's
prospects, properties and business detailed in the Company's most
recent quarterly and annual report and AIF filings.  Should one or more
of these risks and uncertainties materialize, or should underlying
assumptions prove incorrect, actual results may vary materially from
those described in forward-looking statements.  Investors are cautioned
against attributing undue certainty to forward-looking statements.

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

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Copyright (c) 2012 PACIFIC RIM MINING CORP. (PMU)  All rights reserved.
 For more information visit our website at
http://www.pacrim-mining.com/ or send mailto:general@pacrim-mining.com
Message sent on Mon Jun 4, 2012 at 6:18:25 AM Pacific Time
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