Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net cash used for operating activities	$ (1,070)	$ (910)
Investing activities
Expenditures for property, plant and equipment and acquisition of mineral interests	(4,649)	(4,876)
Proceeds from the sale of property, plant and equipment	135	44
Other	(15)	(15)
Net cash used for investing activities	(4,529)	(4,847)
Financing activities
Additions to long-term debt	3,348	170
Reductions of long-term debt	(2,689)	(357)
Net additions (reductions) to revolving credit agreements	2,000	(2,000)
Cash dividends paid	(1,445)	(1,374)
Net cash provided by (used for) financing activities	1,214	(3,561)
Cash and cash equivalents
Total decrease for the period	(4,385)	(9,318)
Balance at the beginning of the period	86,005	88,450
Balance at the end of the period	$ 81,620	$ 79,132