10. WORKERS' COMPENSATION AND PNEUMOCONIOSIS

The changes in the workers' compensation liability, including current and long-term liability balances, for each of the periods presented were as follows:


		Three Months Ended
		March 31,
		2017		2016
	(in thousands)
Beginning balance		$	48,131	$	54,558
Accruals increase			1,974		3,237
Payments			(2,925)		(2,723)
Interest accretion			420		492
Ending balance		$	47,600	$	55,564

Certain of the ARLP Partnership's mine operating entities are liable under state statutes and the Federal Coal Mine Health and Safety Act of 1969, as amended, to pay pneumoconiosis, or black lung, benefits to eligible employees and former employees and their dependents. Components of the net periodic benefit cost for each of the periods presented are as follows:


		Three Months Ended
		March 31,
		2017		2016
	(in thousands)
Service cost		$	546	$	648
Interest cost			629		627
Amortization of net actuarial gain (1)			(567)		(661)
Net periodic benefit cost		$	608	$	614

(1)

Amortization of net actuarial gain is included in the Operating expenses (excluding depreciation, depletion and amortization) line item within our condensed consolidated statements of income.