Leases (Tables)

6 Months Ended

Jun. 30, 2021

The components of lease expense during the three and six months ended June 30, 2021 and 2020 were as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
	(Dollars in millions)
Operating lease cost:
Operating lease cost	$	4.6	$	8.4	$	10.6	$	17.0
Short-term lease cost	3.0		11.6		6.4		21.5
Variable lease cost	0.6		1.6		1.0		2.6
Sublease income	(0.5)		—		(1.0)		—
Total operating lease cost	$	7.7	$	21.6	$	17.0	$	41.1

Finance lease cost:
Amortization of right-of-use assets	$	1.5	$	1.0	$	2.2	$	4.4
Interest on lease liabilities	0.8		0.1		1.2		0.3
Total finance lease cost	$	2.3	$	1.1	$	3.4	$	4.7

Supplemental balance sheet information related to leases at June 30, 2021 and December 31, 2020 was as follows:


	June 30, 2021			December 31, 2020
	(Dollars in millions)
Operating leases:
Operating lease right-of-use assets	$	42.4		$	49.9

Accounts payable and accrued expenses	$	18.7		$	24.5
Operating lease liabilities, less current portion	34.8			42.1
Total operating lease liabilities	$	53.5		$	66.6

Finance leases:
Property, plant, equipment and mine development	$	34.0		$	20.4
Accumulated depreciation	(7.8)			(2.5)
Property, plant, equipment and mine development, net	$	26.2		$	17.9

Current portion of long-term debt	$	15.3		$	21.5
Long-term debt, less current portion	17.0			5.8
Total finance lease liabilities	$	32.3		$	27.3

Weighted average remaining lease term (years)
Operating leases	3.3
Finance leases	6.7

Weighted average discount rate
Operating leases	6.8		%
Finance leases	9.0		%

Supplemental cash flow information related to leases during the three and six months ended June 30, 2021 and 2020 was as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
	(Dollars in millions)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$	4.7	$	6.8	$	12.9	$	19.6
Operating cash flows for finance leases	1.2		0.1		1.9		0.3
Financing cash flows for finance leases	1.5		2.1		2.8		7.9

Right-of-use assets obtained in exchange for lease obligations:
Operating leases	3.7		0.8		6.8		2.1
Finance leases	16.7		0.8		20.3		0.9

The contractual maturities of lease liabilities were as follows:

The contractual maturities of lease liabilities were as follows: