I have a large mound for a big project I have been keeping since we built the house it must be 30x70x4, lots of material to say the least. Its about a 50/50 mix of dirt to rock but its so hard to work with as is and separating it makes it useable. The rock I will use for a base on the driveway to the shop and the dirt now that I can easily grade it will get used in a bunch of projects. The separator does work pretty well and is holding up to the point where I will likely not need to build another.