Abstract: The invention relates to the comminution of brittle material for grinding in a material bed roll mill with two grinding rolls, in which the material for grinding is comminuted between the cylindrical surfaces of the grinding rolls by the application of a grinding force. In order to prevent damage to the roll surfaces due to excessively high surface pressures but to utilise the maximum capacity without exceeding it, the roll surface pressure is continuously monitored and when an upper limit is exceeded the pressure is reduced to a permissible value by reducing the grinding force.