And the Powder River Basin, which spans Wyoming and Montana, has become America's major source of coal in the past decade, relieving overmined Kentucky and West Virginia.

在过去十年里，横跨怀俄明州和蒙大纳的粉河盆地已经成为了美国重要的煤炭来源，缓解了肯塔基州和西弗吉尼亚州的重度开采。