#Coal mining
Jon:
Re: "Hard" vs. "soft" coals. I think that it is just the opposite of what
you stated – anthracite is (or was) much more common in the Eastern states
(i.e., Appalachia), because those coal measures were mostly in older rocks that
had suffered some degree of metamorphism. Out West, most of the productive
coal measures (I believe) are Mesozoic in age and by & large have not been
subjected to prolonged heat & pressure like good ol' West Virginia anthracites.
You might try posting your inquiry in the Earth Forum's "Energy" section. On
occasion, a New Mexico coal geologist lurks around there.
Cheers,
Scott M.