Abstract: Apparatus is provided for controlling the operation of a radial stacker which is adapted to dispense aggregate material in the form of a stack. The radial stacker includes a conveyor for dispensing the aggregate material which moves horizontally through a plurality of dispensing positions to form a level of the stack, and which moves vertically through a plurality of levels to form the stack. One end of the conveyor is supported at a fixed pivot so that it is capable of traversing a horizontal arc of up to 340.degree.. Preposition switches are provided so that the operator may manually set the vertical and horizontal starting point of a cycle. A horizontal drive moves the conveyor horizontally to each position in a level and is controlled by a first timer. A second timer controls the amount of time that the conveyor spends at each of the positions in a level dispensing material.