Other than ~$125M of notes due in 2021, CLF’s nearest debt maturities are now in 2025; from today’s PR (linked in your post):
Given the on-time and on-budget progress of our HBI plant construction, together with the strong free cash flow generation…, there is no reason to wait any longer to redeem these Notes. Mr. Goncalves added, “In addition to reducing our total debt, this redemption brings us one step closer to being in a position to return capital to our shareholders.”
Emphasis added.
Based on CLF’s 2Q18 CC (#msg-142375072), it’s a good bet that the 2021 notes also will be redeemed soon insofar as CLF’s has sufficient cash to pay them off and thereby save on interest payments.