SP-23 1981 Summary of Coal Resources in Colorado Download Publication Details 1981 summary of coal resources in Colorado. 22 pages. Digital PDF download. SP-23D From the Preface: This coal summary initially was prepared for the 1979 Keystone Coal Industry Manual, by D. Keith Murray where it appeared as the Colorado Chapter. In 1983 it was revised to reflect the Colorado coal industry through 1981. Changes mainly occur in the area of historical data and additions to the bibliography. This summary serves as an excellent introduction to Colorado coal augmented by a comprehensive bibliography. Citations Ladwig, L. R. “SP-23 1981 Summary of Coal Resources in Colorado.” Coal Industry. Special Publication. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1981. https://doi.org/10.58783/cgs.sp23.ncee6610/. CGS Publications. https://coloradogeologicalsurvey.org/publications/coal-resources-colorado-1981.