fines would not cause clinkers. fines would restrict the air flow causing more unburned coal
and higher coal
consumption. Higher heat or poorer coal
would cause clinkers.
Higher density coal
= more bone or rock = higher ash. More ash, the more it is likely to fuse into a chunk.
When I burned some lousey coal
in my AA, I was getting clinkers so big, I though I might have to mix ex-lax with the coal