For Coal Block ** I would compound Coal Ore with Saltpeter. You get it almost as often as coal while ore farming in Kelan Cave, so if you farm your own Coal Ore, then you'll have the Saltpeter as well. This will reduce the amount of Organic Muck you need to use in the long run, which Muck may be free, but is a time consuming thing to do. Much more productive, IMHO, to use the saltpeter and not waste time making more muck.