[quote="Yanche]I burned Superior coal for years up until 2-3 years ago. It was red ash and burned hot and well. The coal at that time was deep mined. Today it is apparently not and is mixed from multiple sources. It's burn characteristics have changed and it is judged to inferior to the coal of years ago. The judgement made by a forum member local to the area. I have not burned what they are selling today.[/quote]
I burned superior coal for most of the 2011-2012 heating season. In a hand fed, it was great. Lots of heat, and I didn't get any clinkers with it. It seems to be a mix of mostly white ash, with a little bit of red interspersed.
The nut coal from Mammoth that I burned this year was also excellent, but it sounds like their (under) sizing of rice caused issues for some stoker users.
IMO, the biggest advantage to the UAE coal was it's low ash content.... The lowest of any coal that I've burned. What I didn't like, is its tendency to clinker badly when fired hot. I picked some very gnarly looking clinkers out of my stove. Personally, I would rather dump the ash pan a little more often, than to go fishing thru the firebox for clinkers.