While Wyoming has ten coal fields, only four are currently producing. Our 22 mines produce enough coal to make Wyoming the #I coal producing state.

Coal underlies 54% of the state covering 53,000 square miles. The black areas are deposits close enough to the surface to be strip mined.

Coal was first mined as fuel for the coal fired steam engines of the Union Pacific Transcontinental Railroad. In the early 50's trains shifted to diesel engines and most coal mines closed. In the late 60's the demand for cheap coal for coal fired electrical generating plants rose rapidly and combined with the new huge draglines, shovels, and haul trucks allowed the development of the immense open pit coal mines producing all Wyoming coal today. Ninety eight percent of our coal goes to power plants in 19 states with the rest used as fuel in the sugar beet, cement, bentonite, coke, and phosphate industries.

All of Wyoming coal was formed from peat accumulating in swamps during the Upper Cretaceous (100-65 mya), Paleocene ( 65-50 mya), or Eocene(50-40 mya) time periods. The climate then was subtropical with temperatures averaging in the 80's and rainfall of 120 inches.