I don't know if this story is completely true. The only anthracite coal exists in Pennsylvania. The coal in Utah is high quality bituminous, similar to the low sulfur deposts in parts of Colorado and East KY. The 500 years of coal I mentioned is the soft, sub-bituminous coal around Gillette, WY, reaching into Montana. However, most of the Montana coal is a true bituminous coal with 20 percent more heat. The Powder River coals are exceptional because of the deposit. In most cases, there is 100 feet of coal, covered by 80 feet of overburden--perfect for a big shovel or dragline. The coal continues for hundreds of miles this way and is very cheap to produce. This coal can be ripped with a dozer shank or simply scooped with a power shovel or hoe and needs no blasting to break it out for the trip to the crusher.
Gas is not as abundant as we think and it was and is a catastrophic mistake to base load any large utility boiler on this high rank fuel.
The Powder River coals are exceptional because of the deposit. In most cases, there is 100 feet of coal, covered by 80 feet of overburden--perfect for a big shovel or dragline. Couldn't agree more. I've been involved in the Powder River Basin for a long time. Not only does it have the coals you mention, but contains approx. 26 TCF in gas reserves, which, when fully developed, could heat, cool and power California for 20 years. After the methane is removed, the coal could more safely be extracted.
The "Big George coals by Gillette, are approximately 400' thick with overburdens that vary from 400' to 800'. The CBM wells there are tremendous, some producing over 1 mmcf pd. Central basin coals are deeper and not as thick. Western side of the basin is shallow like the Big George coals around Gillette, but contained in several seams, varing from 10' to 50' in thickness. All in all, a very mineral rich basin, with some very prolific oil and gas wells in deep formations (Muddy, Minnelusa, etc.) from 5000' to 9000'.
Enviro lawsuits against the CBM producers have slowed production, but that is changing over time. As I last understood it, the existing coal mines there are the biggest in the US, but are somewhat idle, due to lack of demand.