Underground mine subsidence in this area has left holes where mine roofs collapsed and created sinkholes at the surface, endangering people and animals through injury or entrapment, rendering land unusable, damaging buildings, roads, and other property, and disrupting or diverting surface and groundwater in ways that affect water availability and sometimes worsen underground mine stability. Several historic underground coal fires have also burned here for more than a century from natural or human causes including past mining activities, wildfires, or spontaneous combustion, polluting the air with toxic gas and smoke, often emitting deadly concentrations of carbon monoxide, and sometimes causing underground explosions by igniting methane or other explosive gases. In 2009, the Wyoming Abandoned Mine Land Program, Sheridan County, and the Wyoming Game and Fish Department partnered to reclaim hazardous conditions left by historic coal mining, creating today’s Kleenburn Recreation Area, and the project received the 2011 Western Regional Abandoned Mine Land Reclamation Award from the U.S. Department of the Interior Office of Surface Mining.