FILE - A haul truck with a 250-ton capacity carries coal after being loaded from a nearby mechanized shovel at the Spring Creek strip mine near Decker, Mont., Nov. 15, 2016. The mine is in the Powder River Basin of Montana and Wyoming, a sparsely populated region with the largest coal mines in the U.S., which is the front line in the political battle over the fuel. (AP Photo/Matthew Brown, File)