Abstract: The device comprises a variable height metering door located over a conveyor used to remove material from a bunker. The door is pivotable, so that rogue material such as pit props may pass it, and is movable up and down relative to the conveyor, so that the depth of material on the conveyor is variable. The door may be moved by moving a frame on which it is mounted, for instance by use of hydraulic or pneumatic rams or a turnbuckle. The height of the door above the conveyor may be determined in response to signals received from sensors associated with the bunkering system.