The plant consists of a series of preliminary comminution machines for preparing the various constituents, some of which having a diameter of over 30 mm. Following pre-crushing, the individual constituents are conducted into pre-assigned storage silos of the required moistness. The pre-crushed materials are then automatically and continuously withdrawn from a computerized weigh system. In this manner it can be ensured that the constituents are available in the proper percentages in conformity with the predefined formula. The proportioned materials reaches the preliminary silo in front of the mill via belts. The mill is a roller mill constructed of purpose-made, especially robust steels, which yields a better grinding result than can be obtained with spherical roller mills of classical construction as are typically used in industrial ceramics for dry grinding.