(New throughout, adds background, comment on Zambia copper mine)
April 28 (Reuters) - Barrick Gold Corp is targeting the sale of up to a 50 percent stake in its Zaldivar copper mine in Chile but would consider selling a bigger stake if it got a "knock-out" offer, company co-president Kelvin Dushnisky said.
Speaking on a conference call to discuss Barrick's first-quarter earnings, Dushnisky said the miner would consider giving up operational control of the open-pit copper mine to a buyer if it believed that would generate more value for shareholders.
Barrick, the world's biggest gold miner, revealed on Monday that it has started the process of selling a stake in its Zaldivar asset in northern Chile. The sale is part of Barrick's plan to cut its debt by $3 billion by year end.
Dushnisky said Barrick's Lumwana copper mine in Zambia is not up for sale at this point.
The Lumwana mine is free cash-flow positive at current copper prices and at Zambia's new, recently reduced royalty rate, he said. (Reporting by Nicole Mordant in Vancouver; Editing by Bernard Orr and David Gregorio)