Note 4 - Other Long-term Assets (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Schedule of Other Assets, Noncurrent [Table Text Block]

	March 31,		December 31,
	2022		2021
Advanced coal royalties	$	6,668	$	6,678
Other		1,665		1,694
Total other assets	$	8,333	$	8,372