Cobre's (ASX:CBE) Chilean unit Sierra Cobre increased its position to majority ownership in the Sierra Atacama Copper Project in Chile, following the issuance of new convertible non-voting preference shares under a $12 million capital raise by Sierra Atacama, according to a Monday Australian bourse filing.

The company said the preference shares will convert to ordinary shares ranking equally with existing ordinary shares upon Cobre Chile exercising its control option to acquire additional shares from Minera Salara Blanco in each of Sierra Atacama and Bergbau Wagen, with the purchase price for the control option set at $12 million and to be exercised by Dec. 31.

Upon exercise of the control option and conversion of the preference shares, Cobre Chile will hold a 62.86% interest in each of Sierra Atacama and Bergbau Wagen and obtain control, the filing added.

The company's shares rose past 1% in recent Monday trade.