DEBT

A summary of long-term debt is as follows:



(In thousands)	June 30, 2016		September 30, 2015
6.5% Senior Notes due February 2020 ("Senior Notes")	$	489,780	$	648,268
Revolving Credit Facility	885,000		1,030,000
Total long-term debt	$	1,374,780	$	1,678,268

Senior Notes (Due February 2020)

As of June 30, 2016, $490.7 million aggregate principal amount of our Senior Notes were outstanding. Our Senior Notes are presented in the table above together with the unamortized premium from their issuance of $3.8 million and $5.9 million and net of unamortized debt issuance costs of $4.7 million and $7.7 million as of June 30, 2016 and September 30, 2015, respectively. Our Senior Notes are unsecured obligations and are not guaranteed by any of our subsidiaries.

Gains on extinguishment of debt— During the nine months ended June 30, 2016, we repurchased, through open market transactions, $159.3 million aggregate principal amount of our Senior Notes at an aggregate cost of $102.5 million, including accrued interest. As a result of the repurchases, we recognized a total gain on debt retirement, net of the write-off of debt issuance costs and premium, of $58.9 million ($44.1 million net of tax, or $0.68 per diluted share) in Gains on extinguishment of debt on the Condensed Consolidated Statements of Operations for the nine months ended June 30, 2016. The repurchases were made using available cash balances.

Revolving Credit Facility

On March 25, 2016, we entered into an amendment to our senior secured revolving credit facility (the "Credit Facility") that, among other things, effective on March 28, 2016, (i) removes the maximum leverage ratio and maximum secured leverage ratio financial covenants, (ii) amends the minimum interest expense coverage ratio such that it is not applicable until the quarter ending September 30, 2018, and decreases the minimum ratio required to 1.15:1.00, (iii) adds a minimum liquidity financial covenant of $150 million, (iv) revises the restricted payments covenant to prohibit us from paying dividends, (v) reduces the total commitments under the Credit Facility by $152 million, and (vi) permits the incurrence of up to $400 million of second lien debt, subject to the parameters set forth therein. After giving effect to the amendment, commitments under the Credit Facility are $1.395 billion through May 2018 and $1.12 billion through May 2019. As a result of the amendment, borrowings under the Credit Facility will bear interest at the Eurodollar rate plus a margin ranging from 2.50% to 3.25% and the commitment fee on the unused portion of the underlying commitment ranges from 1.00% to 1.30% per annum, in each case based on our corporate credit ratings.

In connection with the amendment, we mortgaged the Atwood Achiever, the Atwood Advantage and the Atwood Orca, as additional collateral under the Credit Facility, as well as pledged the equity interests in our subsidiaries that own, directly or indirectly, these three vessels. Additionally, the Atwood Eagle and Atwood Falcon, along with the pledged equity interests in certain of our subsidiaries that, directly or indirectly, own these two vessels, were removed as collateral under the Credit Facility. On April 13, 2016, the Atwood Falcon sale and recycling transaction closed and title of the vessel and associated equipment and machinery transferred to a third party buyer. Our interest in the two drillships under construction remain unencumbered by the Credit Facility.

As of June 30, 2016, our Credit Facility had $1.395 billion of total commitments and we had $885 million of outstanding borrowings. As of June 30, 2016, we had approximately $510 million available for borrowings under the Credit Facility. Approximately $275 million of the commitments mature in May 2018 and approximately $1.12 billion of the commitments under the Credit Facility mature in May 2019.

Obligations under the Credit Facility are secured primarily by first preferred mortgages on nine of our drilling units (Atwood Aurora, Atwood Beacon, Atwood Condor, Atwood Mako, Atwood Manta, Atwood Osprey, Atwood Achiever, Atwood Advantage and Atwood Orca), as well as liens on the equity interests of our subsidiaries that own, directly or indirectly, such drilling units. We were in compliance with all financial covenants under the Credit Facility as of June 30, 2016 and we anticipate that we will continue to be in compliance for the next 12 months.

The weighted-average effective interest rate on our long-term debt was approximately 4.4% per annum as of June 30, 2016. The effective rate was determined after giving consideration to the effect of our interest rate swaps accounted for as hedges and the amortization of debt issuance costs and our debt premiums. Interest capitalized for the three and nine months ended June 30, 2016 was approximately $4 million and $13 million respectively. Interest capitalized for the three and nine months ended June 30, 2015 was approximately $6 million and $15 million respectively.