grain silos for cattle feeding . undergraund
Dig a big hole, put up some form-work, fill in the outside of the form-work with dirt, pour concrete into form-work, remove inner form-work, fill with grain. Though why you would want to is beyond me as you would need to add complex machinery to bring the grain back up to the surface. Better to build the thing above ground and let gravity do the work for you. By the way, the word is underground
