Much of the Powder River Basin coal is sub-bituminous to bituminous. Definitely only thermal coal. But low in sulfur, which in the 70-80's was an oh so relieving answer to acid rain. Then the government-greenie complex went on to concoct other problems such as carbon pollution in order to attack.

I was based at one mine that averaged about 8000 BTU's on the northern end of the Basin and covered some of the mines in the southern end of the Basin that were a bit better at 9000-9500 BTU's. And also covered one in Colorado that was higher at 10,000+ BTU's. That was the Colowyo Mine near Craig, Colorado that the Wild Earth Guardians almost manage to shut down entirely last summer and fall. That mine directly feeds the Tri-State Plant just outside of Craig. Shut down the mine, you shut down the plant and thousands in a rural community are out of work. And electricity.

As usual, the coal industry is way more complex that one would think. Power plants are actually designed to handle certain types of coal, based upon metallurgical aspects. Some coals are higher in ash content than others, some are higher in sodium. The furnaces are setup at different plants to accommodate their source of coal. This interdependence of design, contracts, and customer relations can be complex. When a certain type of coal mines are forced to shut down, the downstream ramifications are like dominoes.