Silver streaming firm Silver Wheaton will purchase 25% of the silver production from Barrick Gold's Pascua-Lama project in South America over the course of its life.
The company has also agreed to acquire all silver produced from Barrick's Veladero, Pierina and Lagunas Norte mines until the end of 2013.
The firm will pay Barrick $625m over three years and continuous payments of $3.90/oz of silver delivered under the agreement.
Pascua-Lama is a key Barrick growth asset and is the third largest silver deposit in the world, with an estimated mine life of over 25 years, Silber Wheaton said.
Barrick has provided Silver Wheaton with a completion guarantee, requiring them to complete Pascua-Lama to at least 75% of design capacity by the end of 2015.