Note 7: Debt

Debt is detailed as follows:



	Effective	June 30	December 31	June 30
in thousands	Interest Rates	2016	2015	2015
Short-term Debt
Bank line of credit expires 2020 1, 2, 3	n/a	$ 0	$ 0	$ 138,500
Total short-term debt		$ 0	$ 0	$ 138,500
Long-term Debt
Bank line of credit expires 2020 1, 2, 3	1.25%	$ 235,000	$ 235,000	$ 0
10.125% notes due 2015	n/a	0	0	150,000
6.50% notes due 2016	n/a	0	0	0
6.40% notes due 2017	n/a	0	0	0
7.00% notes due 2018	7.87%	272,512	272,512	272,512
10.375% notes due 2018	10.63%	250,000	250,000	250,000
7.50% notes due 2021	7.75%	600,000	600,000	600,000
8.85% notes due 2021	8.88%	6,000	6,000	6,000
Industrial revenue bond due 2022	n/a	0	0	14,000
4.50% notes due 2025	4.65%	400,000	400,000	400,000
7.15% notes due 2037	8.05%	240,188	240,188	240,188
Other notes 3	6.24%	489	498	613
Unamortized discounts and debt issuance costs	n/a	(21,531)	(23,734)	(25,975)
Unamortized deferred interest rate swap gain 4	n/a	0	0	523
Total long-term debt including current maturities		$ 1,982,658	$ 1,980,464	$ 1,907,861
Less current maturities		131	130	14,124
Total long-term debt		$ 1,982,527	$ 1,980,334	$ 1,893,737
Total debt 5		$ 1,982,658	$ 1,980,464	$ 2,046,361
Estimated fair value of long-term debt		$ 2,272,149	$ 2,204,816	$ 2,140,942


1	Borrowings on the bank line of credit are classified as short-term debt if we intend to repay within twelve months and as long-term debt otherwise.
2	The effective interest rate is the spread over LIBOR as of the most recent balance sheet date.
3	Non-publicly traded debt.
4	The unamortized deferred gain was realized upon the August 2011 settlement of interest rate swaps as described in Note 6.
5	Face value of our debt is equal to total debt less unamortized discounts and debt issuance costs, and unamortized deferred interest rate swap gain, as follows: June 30, 2016 — $2,004,189 thousand, December 31, 2015 — $2,004,198 thousand and June 30, 2015 — $2,071,813 thousand.

Our total debt is presented in the table above net of unamortized discounts from par, unamortized deferred debt issuance costs and unamortized deferred interest rate swap settlement gain. Discounts and debt issuance costs are amortized using the effective interest method over the terms of the respective notes resulting in $2,203,000 of net interest expense for these items for the six months ended June 30, 2016.

The estimated fair value of our debt presented in the table above was determined by: (1) averaging several asking price quotes for the publicly traded notes and (2) assuming par value for the remainder of the debt. The fair value estimates for the publicly traded notes were based on Level 2 information (as defined in Note 5) as of their respective balance sheet dates.

LINE OF CREDIT

In June 2015, we cancelled our secured $500,000,000 line of credit and entered into an unsecured $750,000,000 line of credit (incurring $2,589,000 of transaction fees).

The line of credit agreement expires in June 2020 and contains affirmative, negative and financial covenants customary for an unsecured facility. The primary negative covenant limits our ability to incur secured debt. The financial covenants are: (1) a maximum ratio of debt to EBITDA of 3.5:1, and (2) a minimum ratio of EBITDA to net cash interest expense of 3.0:1. As of June 30, 2016, we were in compliance with the line of credit covenants.

Borrowings on our line of credit are classified as short-term debt if we intend to repay within twelve months and as long-term debt if we have the intent and ability to extend repayment beyond twelve months. Borrowings bear interest, at our option, at either LIBOR plus a credit margin ranging from 1.00% to 2.00%, or SunTrust Bank’s base rate (generally, its prime rate) plus a credit margin ranging from 0.00% to 1.00%. The credit margin for both LIBOR and base rate borrowings is determined by either our ratio of debt to EBITDA or our credit ratings, based on the metric that produces the lower credit spread. Standby letters of credit, which are issued under the line of credit and reduce availability, are charged a fee equal to the credit margin for LIBOR borrowings plus 0.175%. We also pay a commitment fee on the daily average unused amount of the line of credit that ranges from 0.10% to 0.35% determined by either our ratio of debt to EBITDA or our credit ratings, based on the metric that produces the lower fee. As of June 30, 2016, the credit margin for LIBOR borrowings was 1.25%, the credit margin for base rate borrowings was 0.25%, and the commitment fee for the unused amount was 0.15%.

As of June 30, 2016, our available borrowing capacity was $475,160,000. Utilization of the borrowing capacity was as follows:

$235,000,000 was borrowed

$39,840,000 was used to provide support for outstanding standby letters of credit

TERM DEBT

All of our term debt is unsecured. All such debt, other than the $489,000 of other notes, is governed by two essentially identical indentures that contain customary investment-grade type covenants. The primary covenant in both indentures limits the amount of secured debt we may incur without ratably securing such debt. As of June 30, 2016, we were in compliance with all of the term debt covenants.

In December 2015, we repaid our $150,000,000 10.125% notes due 2015 via borrowing on our line of credit. In August 2015, we repaid our $14,000,000 industrial revenue bond due 2022 via borrowing on our line of credit. These repayments did not incur any prepayment penalties.

In March 2015, we issued $400,000,000 of 4.50% senior notes due 2025. Proceeds (net of underwriter fees and other transaction costs) of $395,207,000 were partially used to fund the March 30, 2015 purchase, via tender offer, of $127,303,000 principal amount (32%) of the 7.00% notes due 2018. The March 2015 debt purchase cost $145,899,000, including an $18,140,000 premium above the principal amount of the notes and transaction costs of $456,000. The premium primarily reflects the trading price of the notes relative to par prior to the tender offer commencement. Additionally, we recognized $3,138,000 of net noncash expense associated with the acceleration of a proportional amount of unamortized discounts, deferred debt issuance costs, and deferred interest rate derivative settlement gains and losses. The combined first quarter 2015 charge of $21,734,000 is presented in the accompanying Condensed Consolidated Statement of Comprehensive Income as a component of interest expense for the six month period ended June 30, 2015.

The remaining net proceeds from the March 2015 debt issuance, together with cash on hand and borrowings under our line of credit, funded: (1) the April 2015 redemption of $218,633,000 principal amount (100%) of the 6.40% notes due 2017, (2) the April 2015 redemption of $125,001,000 principal amount (100%) of the 6.50% notes due 2016 and (3) the April 2015 purchase, via the tender offer commenced in March 2015 of $185,000 principal amount (less than 1%) of the 7.00% notes due 2018. The April 2015 debt purchases cost $385,024,000, including a $41,153,000 premium above the principal amount of the notes and transaction costs of $52,000. The premium primarily reflects the make-whole value of the 2016 notes and the 2017 notes. Additionally, we recognized $4,136,000 of net noncash expense associated with the acceleration of unamortized discounts, deferred debt issuance costs, and deferred interest rate derivative settlement gains and losses. The combined second quarter 2015 charge of $45,341,000 was a component of interest expense for the three and six month periods ended June 30, 2015.

STANDBY LETTERS OF CREDIT

We provide, in the normal course of business, certain third-party beneficiaries with standby letters of credit to support our obligations to pay or perform according to the requirements of an underlying agreement. Such letters of credit typically have an initial term of one year, typically renew automatically, and can only be modified or cancelled with the approval of the beneficiary. All of our standby letters of credit are issued by banks that participate in our $750,000,000 line of credit, and reduce the borrowing capacity thereunder. Our standby letters of credit as of June 30, 2016 are summarized by purpose in the table below:



in thousands
Standby Letters of Credit
Risk management insurance	$ 34,111
Reclamation/restoration requirements	5,729
Total	$ 39,840