Note 2 - Long-lived Asset Impairments	12 Months Ended
Dec. 31, 2022
Notes to Financial Statements
Asset Impairment Charges [Text Block]	(2) LONG-LIVED ASSET IMPAIRMENTS Long-lived assets are reviewed for impairment whenever events or changes in circumstance indicate that the carrying amount of the assets may not be recoverable. Prosperity Mine We recorded an impairment of $1.6 million as of December 31, 2021 on assets consisting of the wash plant and rail facilities at the Prosperity Mine. The wash plant was torn down and the remaining rail was pulled up in the fourth quarter of 2021.

The entire disclosure for the details of the charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value. Disclosure may also include a description of the impaired asset and facts and circumstances leading to the impairment, amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired asset is reported.

No definition available.

Name:	us-gaap_AssetImpairmentChargesTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration