There are approximately 1,736 known abandoned coal mines in the State of Colorado. In 2017 and 2018, on behalf of the State of Colorado Department of Natural Resources Division of Mining Reclamation Safety (DRMS), Tetra Tech, Inc. inspected 38 coal mine fire sites across Colorado. Site conditions included highly active fires, low activity and dormant fires and sites that were previously reclaimed and confirmed as dormant/extinguished. Several coal waste piles were included in the inventory site visits. Several sites exhibit high-intensity indicators of coal combustion including ash, venting, and extremely hot temperatures at the surface. In some instances, the sites were visited on more than one occasion to collect additional data and identify trends in the state of the fires. In addition to coal mine fires, outcrop or paleo fires exist across the state.
