There is a definite method to managing a coal fire and it is always from the outside to the inside. The center is clean burning coke. As the coal around the center portion converts to coke, or "cokes down", it is brought to the center and fresh, green coal is added to the outside edges and wet down with the sprinkling can. As the coal converts to coke, it may fuse into a ring and need to be broken up in order to be brought into the center.
     As you can see, the fire requires careful planning and management. This is probably the most difficult aspect of using coal, as you need a hot clean fire in order to do any decent work.