Natural Gas And US Electricity -- An Analysis

Don sent me a link to a most interesting series on using natural gas in lieu of coal to convert fossil energy to electricity in the United States. He starts with part 4 of a five-part series. Something for the archives. Note the bottom line:

There was 315 GW of coal-fired capacity in the US in 2011. The IEA estimated that of the 315 GW, 16 GW would be unlikely to shut down in favor of natural gas power generation (as it was fueled by very cheap lignite coal located close to the mine) even at gas prices of $2.50 to $4.00 per MMBtu.

I wonder if the bulk of that cheap lignite coal is not coming from North Dakota?