Abstract: The invention relates to ranging drum shearers having cutting drums driven by electric motors mounted on the respective ranging arms. A coal sizer is pivotably mounted on a shroud of the motor and is maintained at a constant disposition regardless of the position of the ranging arm. The coal sizer is maintained at a constant disposition through a control arm pivotally mounted to the pivot axis of the ranging arm and having a keyway containing a key on the axis of the coal sizer. The key and keyway provide for longitudinal movement of the coal sizer relative to the shearer body whereby on the pivotal movement of the ranging arm, the control arm remains stationary and the distance between the key and the axis of the shroud is maintained by the longitudinal adjustment of the coal sizer in the keyway.