Have a look here. They have some top views of Lime and Dust silos.
Dust Silos & Additive Tanks For Sale - Aggregate Systems
they look very similar to the ones in the photo you are using.
also be aware that old silos are like people... no two are the same.
given when they were built, the laws on how a silo was built,and what
equipment it must have, were different then they are today.