Google has released some amazing new time-lapse images of changes on the earth's surface between 1984 and 2012.
The project, called Timelapse, was a joint project of Time, NASA and the United States Geological Survey using satellite images from the Landsat Program.
According to a report by the US Energy Information Administration coal production data for 2012 show that 9 out of the top 10 producing coal mines in the United States are located in Wyoming.
Coal mining in the country is so concentrated in the state that the top two producing mines in Wyoming alone account for 20% of total US coal production by tonnage.
Collectively, the top 10 mines accounted for 38% of total US coal production by tonnage in 2012.