A gate valve system includes a base plate and a gate valve plate, a casting plant includes the gate valve system, and a casting process manufactures workpieces, particularly from metal materials. The base plate has an opening and the gate valve plate has a first opening and at least a second opening. The separating gate valve system is set up so that the separating gate valve system can be brought into casting, pressing, and closure positions. In the casting position, the first opening is arranged to align with the opening of the base plate, at least to the greatest possible extent; in the pressing position, the second opening is arranged to align with the opening of the base plate, at least to the greatest possible extent; and in the closure position, the gate valve plate closes off the opening of the base plate.