A machine in which the coal is hewed from the solid by 10 rotating chipping heads in 2 rows of 5, each with the lower row in advance of the upper. Each head consists of a bit supplemented by widely spaced teeth, each tooth being stepped back to the outside of the head. The circular kerfs made by the heads overlap, and as the machine moves forward, the effect is to break the coal ahead of the teeth into the free spaces, thereby minimizing the production of fines.