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CERTIFICATION

I, Thomas C. Shrake, certify that:

1. I have reviewed this annual report on Form 40-F of Pacific
Rim Mining Corp.;

2. Based on my knowledge, this report does not contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements made, in light of the circumstances under which such
statements were made, not misleading with respect to the period covered by this
report;

3. Based on my knowledge, the financial statements, and other
financial information included in this annual report, fairly present in all
material respects the financial condition, results of operations and cash flows
of the issuer as of, and for, the periods presented in this report;

4. The issuers other certifying officer and I are responsible
for establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over
financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f))
for the issuer and have:

(a)
Designed such disclosure controls and procedures, or caused such disclosure
controls and procedures to be designed under our supervision, to ensure that
material information relating to the issuer, including its consolidated
subsidiaries, is made known to us by others within those entities, particularly
during the period in which this report is being prepared;

(b)
Designed such internal control over financial reporting, or caused such internal
control over financial reporting to be designed under our supervision, to
provide reasonable assurance regarding the reliability of financial reporting
and the preparation of financial statements for external purposes in accordance
with generally accepted accounting principles;

(c)
Evaluated the effectiveness of the issuers disclosure controls and procedures
and presented in this report our conclusions about the effectiveness of the
disclosure controls and procedures, as of the end of the period covered by this
report based on such evaluation; and

(d)
Disclosed in this report any change in the issuers internal control over
financial reporting that occurred during the period covered by the annual report
that has materially affected, or is reasonably likely to materially affect, the
issuers internal control over financial reporting; and

5. The issuers other certifying officer(s) and I have
disclosed, based on our most recent evaluation of internal control over
financial reporting, to the issuers auditors and the audit committee of the
issuers board of directors (or persons performing the equivalent
functions):

(a) All
significant deficiencies and material weaknesses in the design or operation of
internal control over financial reporting which are reasonably likely to
adversely affect the issuers ability to record, process, summarize and report
financial information; and

(b) Any
fraud, whether or not material, that involves management or other employees who
have a significant role in the issuers internal control over financial
reporting.

|Date: July 18, 2008 | By: |                        
|------------------- | --- | -----------------------
|                    |     | Thomas C. Shrake     
|                    |     | Thomas C. Shrake       
|                    |     | Chief Executive Officer

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