Projects

El Dorado

In January 2005 Pacific Rim released the results of a pre-feasibility study on the Minita deposit. The pre-feasibility study considers all aspects of a proposed operation at the Minita deposit, including an underground mine plan, metallurgy and processing, tailings impoundment, environmental matters, and capital and operating costs, and offers an economic evaluation of the Minita reserves. It does not include other current resources nor does it yet include the results of recent drilling by the Company at the South Minita and Nance Dulce gold zones discovered in mid-2004. The most compelling outcome of the study is that, at $163 per gold equivalent ounce, operating costs at the Minita deposit are within the lowest quartile on a world-wide basis.

Highlights from the Minita pre-feasibility study include (all monetary amounts in United States dollars; gold equivalent ounces based on $400 per gold ounce and $6.00 per silver ounce):

• Operating costs averaging $163 per gold equivalent ounce over the life of mine; including $140 and $137 per ounce operating cost in the first two years of production respectively.
• A proven and probable reserve of 490,758 ounces of gold and 3,138,016 ounces of silver at a cut-off grade of 5 g/t gold.
• Average annual gold equivalent production over a projected 6.2-year mine life of 80,497 ounces; including 87,346 and 98,576 gold equivalent ounces in the first two years of production respectively.
• Total capital costs of $66.9 million; $47.9 million pre-production capital and $19.0 million on-going capital.
• $43.6 million in free cash flow over the life of the mine with a payback period of 3.5 years (based on a gold price of $400 per ounce and a silver price of $6.00 per ounce).
• Projected pre-tax Internal Rate of Return ("IRR") of 18.1% based on a gold price of $400 per ounce and a silver price of $6.00 per ounce.

The Minita pre-feasibility study results are summarized in the following table (all monetary values in US dollars):

PRODUCTION SUMMARY
Mining and Processing Rate	750 tonnes per day
Run of Mine Ore to Mill	1,630,889 tonnes at 9.5 g/t gold and 60.3 g/t silver
Metal to Mill	497,101 ounces gold, 3.2 million ounces silver
Recovery	92% gold, 88.3% silver
Average Production	80,497 gold equivalent ounces
Peak Production	98,576 gold equivalent ounces
Mine Life (production)	6.2 years
Gross Revenue (at $400 gold and $6.00 silver)	$199.3 million
Net Smelter Return	$197.8 million
Royalties (2% government, 1.5% underlying owner)	$6.3 million
Gross Income from Mining	$191.5 million
OPERATING COSTS
Mining	$44.3 million
Processing	$22.8 million
Administrative	$13.9 million
Total	$81.0 million
Average Cash Cost per gold equivalent ounce	$163
CAPITAL COSTS
Equipment	$30.5 million
Capitalized costs	$36.4 million
Total	$66.9 million
Pre-production portion	$47.9 million
On-going portion	$19.0 million
FINANCIAL ANALYSIS
Payback (from start of milling)	3.5 years
Net Present Value @ 0%	$43.6 million
Internal Rate of Return	18.1%

The Minita pre-feasibility study resulted in the conversion of a portion of the Minita resource into proven and probable reserves. This conversion was based on the stope outlines and dimensions for resources at or above a diluted 5 g/t equivalent gold cut-off grade, where dilution was calculated on a block by block basis to account for the variability associated with variations in the vein thickness. The Minita reserve estimate eliminated those resources contained within the unrecoverable portions of the crown and sill pillars and incorporates planned dilution, unplanned dilution, backfill dilution and production losses. The total proven and probable reserve for the Minita deposit is 1,604,883 tonnes at an average grade of 9.51 g/t gold and 60.82 g/t silver for a total of 490,758 ounces of gold and 3,138,016 ounces of silver, or 535,586 gold equivalent ounces.

El Dorado Project Proven & Probable Reserves (as of January 21, 2005)
	Tonnes	Grade	Ounces	Grade	Ounces	Grade	Ounces
		(g Au/t)	(Au)	(g Ag/t)	(Ag)	(g AuEq/t)	(AuEq)
Proven	711,949	10.09	230,908	68.30	1,563,425	11.06	253,242
Probable	892,934	9.05	259,850	54.85	1,574,591	9.84	344
Total	1,604,883	9.51	490,758	60.82	3,138,016	10.38	535,586
Notes:
1) El Dorado Project proven and probable reserves at 5 g/t equivalent gold cut-off grade.
2) Reserves derived from cutoff grades based upon US$350/oz gold and US$5.00/oz silver market price.
3) Values shown in table are diluted and do account for mining recovery.

Note to US Investors: These reserves have been calculated in accordance with National Instrument 43-101, which differs significantly from the requirements for reserve disclosure under SEC Industry Guide 7. Industry Guide 7 requires a "final" or "bankable" feasibility study to make reserve disclosure. Readers are refered to Cautionary Notes for further information.