Commitments and Contingent Liabilities (Tables)

12 Months Ended

Dec. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Schedule of black lung benefit liabilities

The following table summarizes discount rates utilized, active claims and the total black lung liabilities:

	December 31,
	2022			2021
Discount rate(1)	4.9		%	2.4		%
Active claims	332			332
Total black lung liability (dollars in millions)(2)	$	58.1		$	63.3

(1)The discount rate is determined based on a portfolio of high-quality corporate bonds with maturities that are consistent with the estimated duration of our black lung obligations. A decrease of 25 basis points in the discount rate would have increased black lung expense by $1.1 million in 2022.

(2)The current portion of the black lung liability was $5.9 million and $5.4 million at December 31, 2022 and 2021, respectively, and was included in accrued liabilities on the Consolidated Balance Sheets.

The following table summarizes annual black lung payments and (benefit) expense:

	Years Ended December 31,
	2022		2021		2020
	(Dollars in millions)
Payments	$	5.0	$	4.4	$	6.0
(Benefit) expense (1)	$	(0.2)	$	3.1	$	15.4

(1)Black lung (benefit) expense incurred in excess of annual accretion of the black lung liability reflects the impact of changes in discount rates, current filing and approval rate assumptions and/or other changes in our actuarial assumptions.