1975 summary of coal resources in Colorado. 17 pages. Digital PDF download. SP-09D
This 1975 publication was the first of the coal resources summaries, which served to provide not otherwise available information on the coal resources of the state. It was subsequently updated in 1979 by SP-13, after which more detailed analysis of historical data, geology of coal fields and regions, and the total coal resources of the state was provided in SP-23, SP-24, SP-36 and SP-41.