They are tall buildings housing a number of large cylindrical bins. They are 60 to 90 feet high and may each hold 1,000 tonnes of grain. The silo is equipped with mechanical elevators for dealing with wheat wich invariably arrives by road to the mill. The cleaning section or screen room draws wheat from the silo. Here wheat is first cleaned on sieves which removes all the impurities different in size from the wheat grain.
Magnets next remove any fragments of iron or steel.
Further equipment then take out impurities similar in size but different in shape from the wheat grain, such as foreign cereals or round seeds. An old-fashioned watermill.