HIFLD OPEN

This dataset is a polygon shapefile representing the most recent update of the coal fields of the conterminous United States. Scale of data is 1:5,000,000. This publication is based on a USGS paper map that was a representation of the coal fields and major regions of the time (Trumbull, 1960). Trumbull's 1960 map was digitized and coal fields from the Gulf Coast were added to create USGS OFR 96-92, Coal Fields of the Conterminous United States (Tully, 1996). Tully's (1996) publication consisted of a map in pdf format that could be printed, and an ArcInfo coverage of the coal fields, attributed with rank and potential economic use (minability) of the coal. This new dataset includes a pdf showing updated coal fields and a shapefile that contains attributes on coal rank (without regard to outdated economic standards), province, name, and age. The data used to update Tully's (1996) digital map was collected from the National Coal Resource Assessment (NCRA) regional Professional Papers produced by the USGS and from AAPG Discovery Series 14/Studies in Geology 62, all of which were conducted by USGS geologists and professional staff. A small number of field names were added and or updated in the western states of Washington, Oregon, California, Utah, Colorado and New Mexico using additional coal resource literature.The full study is available from USGS: https://doi.org/10.3133/ofr20121205<br>