POSTRETIREMENT MEDICAL BENEFITS AND PENSION (Tables)

3 Months Ended

Mar. 31, 2016

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,
	2016		2015
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	935	$	1,054
Interest cost	3,111		2,907
Amortization of deferred items	200		327
Total net periodic benefit cost	$	4,246	$	4,288

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

	Three Months Ended March 31,
	2016		2015
	(In thousands)
Former mining operations	$	2,135	$	2,034
Current operations	2,111		2,254
Total net periodic benefit cost	$	4,246	$	4,288

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,
	2016			2015
	(In thousands)
Components of net periodic benefit cost:
Service cost	$	608		$	506
Interest cost	2,287			1,985
Expected return on plan assets	(3,231		)	(2,639		)
Amortization of deferred items	1,039			1,110
Total net periodic pension cost	$	703		$	962