OceanaGold Enters Into a Definitive Agreement to Acquire Pacific Rim Mining

OceanaGold Corporation and Pacific Rim Mining Corp. are pleased to announce that the companies have entered into a definitive agreement (the "Agreement") pursuant to which OceanaGold has agreed to acquire all of the issued and outstanding common shares of Pacific Rim in an all-share transaction to be completed by way of a statutory plan of arrangement under the Business Corporations Act (British Columbia) (the "Arrangement"). Pacific Rim's principal asset is the high-grade, El Dorado Gold Project ("El Dorado") in El Salvador.

Benefits for OceanaGold shareholders

• Adds the El Dorado high grade gold-silver resource with significant exploration upside potential. El Dorado has a Measured and Indicated Resource of 1,430,500 ounces gold equivalent (AuEq) grading 10.4 grams AuEq per tonne and an Inferred Resource of 282,400 ounces AuEq grading 10.47 grams AuEq per tonne.
• Aligns well with OceanaGold's strategy to invest in high quality, low cost assets and utilise its proven mine developing capabilities and experience to advance the El Dorado project
• Presents an accretive transaction based on an acquisition value of approximately US$7/oz gold equivalent using Pacific Rim's previously stated total resources
• Provides a first-mover advantage opportunity into a very prospective jurisdiction for precious metals

Benefits for Pacific Rim shareholders

• Provides an opportunity to participate in a leading gold producer through an all-share transaction that allows continued exposure to the development of the El Dorado Project in El Salvador with stronger financial stability
• Provides Pacific Rim shareholders with a 50% premium to the 20 day VWAP as at October 7, 2013
• Diversifies Pacific Rim's asset risk profile and provides exposure to OceanaGold's diversified portfolio of producing gold mines in New Zealand and the Philippines
• Obtains access to OceanaGold's proven skill set to build and operate gold mines internationally in environmentally sensitive and socially complex regions