Coal ash production by basin (IMAGE) University of Texas at Austin Caption Estimated total associated ash from coal production in the United States by basin. About 83% of all ash produced during the period was from the Appalachian, Powder River, and Illinois basins combined. Credit Reedy, et al. Usage Restrictions Include photo credit License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.