Depletion of the coal reserve base is provided by township, coal zone/coal bed and thickness. Historic, geologic, and mining data were compiled for 1,667 recorded coal mines in Colorado. BLM quadrangle index map. 65 pages. 23 figures. 4 tables. 1 plate (1:1,000,000). Digital PDF download. OF-79-01D
Mining in Colorado began in the 1860’s. Most of the coal produced to date has been mined in beds ranging from 4 to 10 feet in thickness in rock units ranging in age from Upper Cretaceous to early Eocene. Using original reserve base estimates calculated by the U.S. Department of Energy, 6.67 percent of the State’s demonstrated coal reserve base has been mined or lost in the process of mining. This leaves 93.33 percent of the original reserve base intact. A summary report covering each of the eight coal regions is included.