Tower silos containing silage are usually unloaded from the top of the pile, originally by hand using a pitchfork, in modern times using mechanical unloaders. Bottom silo unloaders are utilized at times but have problems with difficulty of repair.
An advantage of tower silos is that the silage tends to pack well due to its own weight, except in the top few feet. The tower silo was invented by Franklin Hiram King.
In Australia, many country towns in grain-growing areas have concrete tower silos to collect grain from the surrounding towns and store it ready for transport by train or road to an export port.