So, you want to trust the government, the same government that has been pushing and subsidizing the sub-bituminous coal industry?
Your article says that the sub-bituminous coal has a range of BTU values. That’s because it is a mixture of lignite and Bituminous coal. If you test a piece of bituminous coal you get a higher value than if you pick up a piece of the lignite. The true value is something in between,
Why do you think that Austalian mining companies are pulling back? Why do you think that the price of sub-bituminous coal is dropping precipitously? It doesn’t trade on the same market as real coal. It is not real coal.
I do know of a power plant that was built to run sub-bituminous coal, though. It requires a very expensive rebuild of the power plants to make the switch. This one happens to be a new plant and they haul the sub-bituminous coal all the way from Wyoming, instead of using the real bituminous coal from closer mines. They should have used natural gas.
It is not just that article. And sub-bituminous coal is produced in places other than Powder River Basin in the US.
If you would like another source, how about Purdue University?