Fortescue Metals Group (FMG) has continued to reduce its debt by repaying $US1.6 billion ($1.77 billion) of senior unsecured notes.
Shares in the miner lifted 3.5% to $5.335 at the 1015 AEDT official market open, against a benchmark index rise of 0.77%.
In a statement to the Australian Securities Exchange, Fortescue said it has issued voluntary redemption notices for the remaining $US1.04 billion senior unsecured notes due in 2015, and the $US600 million senior unsecured notes due in 2016.
The notes will be redeemed on March 14.
The miner said the announcement takes total debt repayments since November 2013 to $US3.07 billion.
Fortescue said its gross debt peaked at $US12.7 billion but after the redemption of the notes and other capital management initiatives undertaken, gross debt will fall to $US9.6 billion by the end of March.
Chief financial officer Stephen Pearce said the measures continue to reduce Fortescue's gearing towards 40 per cent.
"The combination of voluntary debt repayments of $US3.07 billion, in addition to successfully lowering the cost of remaining debt, represents an annual interest saving of more than $US300 million per annum," Mr Pearce said.
The miner said in November it would repay $US1 billion of senior unsecured notes due in 2015, saving $US70 million a year in interest.