Not yet, will have to figure out what is best to use...
When I bought the Burrell there was a fellow in the Midwest somewhere...can't recall his name right now but I will look for the receipt- anywho he had an eBay store(large scale live steam stuff) with good Welsh coal. Haven't found a clinker yet and it burns well. Don't know where he was getting it but...
If you do run on coal be prepared for the clean-up. I was exhausted after 6 hours running and 3 more cleaning the engine back up. It's super critical to clear that ash out or it will pit the metal in a hot minute. I use shotgun brushes for the tubes and a big pipe brush for the chimney. But I have to say, running on coal is relaxing once you hit your rhythm.