Naturally occurring, solid hydrocarbon classified as an asphaltite. Coal-like mineral found almost exclusively in the Uinta valley, near Fort Duchesne, Utah: E. S. Dana, A System of Mineralogy (John Wiley, New York, 6th ed., 1901) p 1020. Review: K. R. Neel in Kirk-Othmer Encyclopedia of Chemical Technology vol. 11 (John Wiley & Sons, New York, 3rd ed., 1980) pp 803-806. Review of uses and mining methods: D. Jackson, Eng. Min. J. 182, 88-91 (July, 1981); of health effects from occupational exposure: D. G. Keimig et al., Am. J. Ind. Med. 11, 287-296 (1987); G. J. Kullman et al., Am. Ind. Hyg. Assoc. J. 50, 413-418 (1989).