Ironic that someone reported th same problem with your beloved Blaschak just recently.Devil505 wrote: I found Reading nut coal was unusable in my TLC2000 due to clinkers jamming the shaker grates all the time. Never had that problem with Blaschak.
Is it a clinker or rock? Sometimes a rock may be called a clinker but it's really not. The big difference is a clinker is formed.
The red ash coal like that from Superior is more prone to this especially when burned very hot. I've seen them the size of softballs and you'd need a pretty good sized sledgehammer if you wanted to break them. It's near impossible to produce with white ash, they will form to some degree but they are easily broken even with your bare hands.