Hi Freddy, I've burnt both high [~14% ] and low [~6% ] ash coal in my AA 260.. the only issue is that really low ash coal will make more and bigger clinkers.. and of course the ash pan will fill up quicker..
Once I got my AA260 burning correctly [you won't have this problem with the AA130] it produced around 1/4 to 1/2 an ash pan full every 24 hours.. this depended on the weather.. and therefore the coal use..
My Coal Hopper holds about a week's worth of coal.. When I'm at work [gone for 5 days] my caretaker swaps the ashpans every day, unless it is only 1/4 full, he doesn't like them when they are full, too heavy for him.. he leaves the full pans in a row next to the boiler for me to empty
With the AA130, your ash pan is smaller, so the weight won't be as much of an issue.. I think the fill-rates will be about the same, really cold weather will mostly fill an ashpan in 24 hours.. of course this will vary with your heating load..
I mix the low and higher ash coal.. I don't understand why, but a 50/50 mix of Superior and UAE seems to burn hotter, and create less ash. Forum member Jpen mentioned to me at the Meet&Greet that he sees the same effect with mixed coal..
I don't think you will go wrong with Either UAE or Superior coal.. UAE is a dry breaker,, the coal has more fines in it, so is a bit 'dirty' to work with,, Superior is washed several times.. That's the major difference I see with the two.