PROPERTY, PLANT AND EQUIPMENT (Tables)

3 Months Ended

Mar. 31, 2021

PROPERTY, PLANT AND EQUIPMENT.

Net Book Value of Property, Plant and Equipment

	Net Book Value of Property, Plant and Equipment at March 31, 2021
(thousands of dollars)	Alabama		Corporate		Total
Mineral rights and properties		8,972		—		8,972
Other property, plant and equipment		—		11		11
Total	$	8,972	$	11	$	8,983

	Net Book Value of Property, Plant and Equipment at December 31, 2020
(thousands of dollars)	Alabama		Corporate		Total
Mineral rights and properties		8,972		—		8,972
Other property, plant and equipment		—		13		13
Total	$	8,972	$	13	$	8,985