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Self Insurance | 12 Months Ended
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Dec. 31, 2018
Self Insurance [Abstract] |
Self Insurance | (10) Self Insurance ﻿ We self-insure our underground mining equipment. Such equipment is allocated among 10 mining units spread out over 22 miles. The historical cost of such equipment is about $255 million. ﻿ As of December 31, 2018, and 2017, restricted cash of $4.6 million and $3.8 million respectively, represents cash held and controlled by a third party and is restricted for future workers’ compensation claim payments. ﻿

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