Ask the dealer where he is getting his coal from. If he is selling high quality coal he will tell you because he knows his product is good. If he won't tell you he doesn't have faith in the product because he knows it's from a questionable source. The only variable is he can lie about where it is from. Before you get a ton or more delivered see if you can pick up a sample from their yard to try out. If they don't want to accommodate you there are plenty of others around.
My father-in-law said if I go to Mount Carmel, to a breaker, I could get it for like $110/ton.
He may be talking about UAE Harmony Coalcorp. It's $150/ton, and very high quality red ash coal (I'm burning it now in the stoker).