Amazing how nobody who reports on this puts forward any numbers.

This Appalachian coal is said to have over 300ppm of rare earth oxides in it.

That means for every ton of coal, we're talking about 300g of material. Compare conventional rare earth ores, where for every ton, we're talking about 90kg (Mountain Pass).

It's nice and all that these things are in coal, but thermal coal's already on its way out, Appalachian thermal coal especially due to its high cost and high sulfur content, and a couple pennies of rare earths per ton is a worse use of resources than Powder River coal + actual rare earth mining.