Apparatus for lifting a conveyor belt from a belt conveyor, the apparatus comprising: a body selectively movable along the belt conveyor; a belt lifting assembly mounted on the body and operable to engage the conveyor belt to lift the belt from, and subsequently lower said conveyor belt onto, an idler roller operatively supporting the belt on the belt conveyor; a robotic arm mounted on the body, the robotic arm having an articulated construction and being autonomous or semi-autonomous and having means arranged for gripping said idler roller from which the conveyor belt has been lifted, said robotic arm configured to replace the idler roller from which the conveyor belt has been lifted; and a controller; wherein the belt lifting assembly comprises a belt support movable between an operative position for engaging the conveyor belt to lift or to lower the conveyor belt, and a retracted position clear of the conveyor belt; the apparatus being characterized in that it is comprising a sensor configured to sense a defective idler roller; and in that the controller is configured to control operation of the apparatus, including: propelling the apparatus along the belt conveyor whilst the sensor senses for a defective idler roller, and controlling the robotic arm and the belt lifting assembly in response to the sensor sensing a defective idler roller in order to lift the conveyor belt and replace the defective idler roller with a new roller in an automated manner; and in that the belt support comprises a pair of support sections each adapted to engage the underside of the conveyor belt from opposed sides thereof when in the operative position, the support sections each being adapted to cooperate to provide support for the conveyor belt; each support section comprises first and second support elements (71, 72), the first support element being adapted to support an adjacent marginal edge portion of the conveyor belt and the second support element being adapted to support a central section of the conveyor belt; the belt support comprises a carrier for moving the pair of support sections into and out of engagement with the conveyor belt, the carrier comprising a pair of carrier arms, each carrying one of the support sections, wherein each carrier arm is mounted for pivotal movement between the operative or retracted position. a body selectively movable along the belt conveyor; a belt lifting assembly mounted on the body and operable to engage the conveyor belt to lift the belt from, and subsequently lower said conveyor belt onto, an idler roller operatively supporting the belt on the belt conveyor; a robotic arm mounted on the body, the robotic arm having an articulated construction and being autonomous or semi-autonomous and having means arranged for gripping said idler roller from which the conveyor belt has been lifted, said robotic arm configured to replace the idler roller from which the conveyor belt has been lifted; and a controller; propelling the apparatus along the belt conveyor whilst the sensor senses for a defective idler roller, and controlling the robotic arm and the belt lifting assembly in response to the sensor sensing a defective idler roller in order to lift the conveyor belt and replace the defective idler roller with a new roller in an automated manner; the belt support comprises a pair of support sections each adapted to engage the underside of the conveyor belt from opposed sides thereof when in the operative position, the support sections each being adapted to cooperate to provide support for the conveyor belt; each support section comprises first and second support elements (71, 72), the first support element being adapted to support an adjacent marginal edge portion of the conveyor belt and the second support element being adapted to support a central section of the conveyor belt; the belt support comprises a carrier for moving the pair of support sections into and out of engagement with the conveyor belt, the carrier comprising a pair of carrier arms, each carrying one of the support sections, wherein each carrier arm is mounted for pivotal movement between the operative or retracted position.