Self Insurance	3 Months Ended
Mar. 31, 2020
Self Insurance [Abstract]
Self Insurance	(12)SELF-INSURANCE We self-insure our underground mining equipment. Such equipment is allocated among seven mining units dispersed over ten miles. The historical cost of such equipment was approximately $271 million and $273 million as of March 31, 2020, and December 31, 2019, respectively. Restricted cash of $4.7 million and $4.5 million as of March 31, 2020, and December 31, 2019, respectively, represents cash held and controlled by a third party and is restricted for future workers’ compensation claim payments.

(12)SELF-INSURANCE

We self-insure our underground mining equipment. Such equipment is allocated among seven mining units dispersed over ten miles. The historical cost of such equipment was approximately $271 million and $273 million as of March 31, 2020, and December 31, 2019, respectively.

Restricted cash of $4.7 million and $4.5 million as of March 31, 2020, and December 31, 2019, respectively, represents cash held and controlled by a third party and is restricted for future workers’ compensation claim payments.