There are seals made of baler belting on the sides of the hopper (visible in one of the later photos). There is also a piece of belt hanging under the grate on each end of the hopper to help seal up the ends of the hopper. I know that grain will still get around these, but hopefully it will help some.

There are angle steel braces welded between the side I-beams, top and bottom on the end buried in the driveway; on the bottom only on the auger end. The top angle steel on the auger end is bolted in so that it can be removed to get the hopper in and out of the pit.

Crushed limestone isn't really available around here but good gravel is plentiful. The stuff I got is the same stuff they use on the gravel roads around here - it packs pretty nice and stays put after that. Concrete is an option in the future but then I'm committed to leaving the dump in this location after that. This way if some thing changes in the future I can dig it out and move it.

I had a similar (smaller) setup like this years ago when I was getting started farming and just had a small dryer and holding bin on anther place. I used 2-16" I-beams for the pit sides, set wide enough to drop the dump of my JD 350 flight elevator into and made a grate out of angle steel salvaged from a round steel corn crib we had torn down. Built up the driveway around it like this one and it worked great for many years. (That pit and grate is still in the grove!) Then we consolidated our drying systems into one and I lost my drive-over dump. It will be nice to have it back now......