Hello cooter, welcome to the forum.
The coal you are burning is Bituminous, the unsorted coal at the coal supplier I bought from called this unsorted coal 'big vein' coal, just as it comes from the mine, not run through a breaker to sort for size.
You can burn unsorted coal, but the biggest problem will be the fines, the fine-ground coal that is like sand.
The fines will burn, but coal needs air passing through and around the coal pieces to burn well, the fines tend to block airflow so they don't burn well. If you toss a large shovel-full of fines on a fire, you can block all airflow and actually put out the fire. The fines act like a blanket and smother the fire.
When I burn bituminous coal, especially with lots of fines, I load fresh coal on the fire, let it burn for 40 minutes or so, then open the loading door and break up the layer of coal with a poker to make air passageways in the coal. Otherwise I end up with large areas of coal that are not burning because the air cannot get through the layer.
The other option is to sift your coal with a fine-toothed pitchfork or through a screen to separate the fines from the pieces of coal. This is what I usually do, I discard the fines.
The sorted coal does cost more than 'big vein' but since you pay for the coal by weight, it may be less expensive to pay for the sorted coal because you are not paying for the fines which don't burn that well or need to be thrown away anyway.
In the West Virginia/Maryland area where I bought Bituminous coal, there are dozens of sources for coal, keep looking, you will find some other places to buy sorted coal that may suit your needs better.
Hope this answers your question, Greg L