Stock Photo: Gillette, Wyoming - An aerial view of a coal train loading facility at a surface coal mine in Wyoming´s Powder River Basin The Powder River Basin is the largest coal mining region in the United States About 80 trains a day move coal from the Basin to po. Gillette, Wyoming - An aerial view of a coal train loading facility at a surface coal mine in Wyoming´s Powder River Basin The Powder River Basin is the largest coal mining region in the United States About 80 trains a day move coal from the