Abstract: A feeder/crusher machine for use in underground coal or ore mines for receiving and crushing mined material and feeding the crushed product to a stationary conveyor in the mine material transport system. It comprises a tramming unit supporting a feeding and crushing unit having an elongated body with a crushing section located intermediate receiving and discharge sections at opposite ends of the body. A conveyor has an upper, carrying run movable through the crushing section in a horizontal plane. A pair of breaker drums are mounted immediately above the conveyor in the crushing section and are rotatable about transversely spaced, parallel vertical axes. Because the breaker drums are rotatable about vertical axes, teeth on their peripheries move horizontally, parallel to the plane of the conveyor carrying run. Further, the teeth move in the same direction as the conveyor at the location between the drums where crushing occurs.