An appeals court in Chile this week blocked Anglo American from selling any further stakes in its Anglo American Sur (AAS) assets in southern Chile, after Corporacion Nacional del Cobre (Codelco) filed an appeal to safeguard its option to buy into them.

Anglo recently announced it had sold a 24.5% in Anglo American Sur SA to Mitsubishi Corp. for $5.39 billion. AAS includes the Los Bronces and El Soldado copper mines and the Chagres copper smelter in Chile. The transaction, according to Anglo American, is unconditional and was completed immediately following agreement of the terms of the transaction.

Codelco, the world’s largest copper producer, said Anglo American is trying to prevent it from exercising an option to buy a 49% stake in Anglo American Sur, and appealed to the Santiago appeals court on Nov. 14, 2011, according to Reuters. “What we are doing now is preventing Anglo American fromcontinuing to sell shares (in Anglo American Sur), and in January, we are going to exercise the option to buy 49%,” said Diego Hernandez, Codelco’s CEO.

In a press statement, Anglo American said it planned to file a response to the injunction and would take other steps as are necessary to protect its rights, hinting at a legal battle between the two mining companies. According to Anglo, the percentage of shares in AAS over which Codelco may exercise its option has now been reduced by the percentage of shares in AAS not held by Anglo American at the time of exercise. Anglo believes that Codelco can now only buy a 24.5% stake after the sale. The option is exercisable only during the month of January every three years until January 2027.

During October, Codelco had secured a $6.75 billion bridging loan from Japan’s Mitsui & Co to allow it to exercise its option and had warned Anglo American that it should honor the agreement.

Chile is a significant part of Anglo’s operations and AAS accounted for 41% of its copper production in 2010. Anglo has invested around $2.8 billion to develop Los Bronces.