A conveyor belt moves material from a loading station to an unloading station. The belt is formed on its two sides with spaced support rollers that move along a support track. The belt is guided over deflection drums in the loading station and in the unloading station. A turning device turns the conveyor belt through about 180° after the deflection drum in the unloading station, and a turning device turns the conveyor belt back through about 180° in front of the deflection drum of the loading station. Each turning device is formed by a support structure similar to a hollow cylinder with two spiral guides on the inside, along which the support rollers can be moved. The two guides lie approximately diametrically opposite one another and execute an angular rotation of about 180° over the length of the support structure.