POSTRETIREMENT MEDICAL BENEFITS AND PENSION (Tables)

3 Months Ended

Mar. 31, 2017

Postretirement Medical Benefits

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Components of net periodic benefit cost

The components of net periodic postretirement medical benefit cost are as follows:

	Three Months Ended March 31,
	2017		2016
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	793	$	935
Interest cost	3,197		3,111
Amortization of deferred items	964		200
Total net periodic benefit cost	$	4,954	$	4,246

The following table shows the net periodic postretirement medical benefit costs that relate to current and former mining operations:

	Three Months Ended March 31,
	2017		2016
	(In thousands)
Former mining operations	$	2,305	$	2,135
Current operations	2,649		2,111
Total net periodic benefit cost	$	4,954	$	4,246

Pension

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Components of net periodic benefit cost

The Company incurred net periodic benefit costs of providing these pension benefits as follows:

	Three Months Ended March 31,
	2017			2016
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	407		$	608
Interest cost	2,630			2,287
Expected return on plan assets	(3,627		)	(3,231		)
Amortization of deferred items	594			573
Total net periodic pension cost	$	4		$	237