A system and method for determining and controlling a speed of a conveyor belt configured for transferring material from a source of the material to a haul vehicle includes a motor and associated head pulley shaft operatively coupled to a conveyor belt head pulley configured for driving the conveyor belt. The motor is connected to a conveyor belt tensioner block configured to enable adjustment of a tension in the conveyor belt, and the head pulley shaft is rotatably supported within the conveyor belt tensioner block. A speed ring gear is mounted on the head pulley shaft and located at least partially within a bore through the conveyor belt tensioner block. A speed sensor is mounted on the conveyor belt tensioner block in a position radially outward from teeth of the speed ring gear as the speed ring gear and head pulley shaft rotate within the bore through the belt tensioner block. The speed sensor is configured to generate signals indicative of the speed of rotation of the head pulley shaft and speed ring gear. A system controller determines a speed of the conveyor belt from the speed of rotation of the head pulley shaft and speed ring gear, and controls the speed of the conveyor belt to control an amount and rate of transfer of material along the conveyor belt from the source of material to the haul vehicle during a time period.