Chile's state copper giant Codelco said on Monday it was willing to consider a formula that ensures it protects the economic value of a disputed stake option in Anglo American's southern Chilean properties.

Codelco said earlier on Monday it had exercised a $6 billion (3.9 billion pounds) option to buy a 49 percent stake in Anglo's mining assets in southern Chile, but global miner Anglo American defied the move, setting the stage for a potentially lengthy legal battle.

World No.1 copper producer Codelco said it wanted Anglo to sell it a 24.5 percent stake in its southern Chilean properties now, and said it would take all measures to safeguard the other half of the option it says it is eligible to buy.

(Reporting by Felipe Iturrieta. Writing by Simon Gardner; Editing by Marguerita Choy)